Name: An Ultrasonic Tool for Nerve Conduction Block in Diabetic Rat Models (Video) | JoVE Journal
Uploaded: 2017-10-20T13:00:00.000+00:00
Duration: 10 min 27 s
Description: Learn high intensity-focused ultrasound for temporary nerve conduction block in diabetic neuropathy using Sprague-Dawley rats. This localized method offers a safe, repeatable approach to analgesia research.

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5 minutes

The study was supported by the Ministry of Science and Technology (Project MOST 105-2221-E-400 -001) and the National Health Research Institutes (Project BN-105-PP-10), Taiwan.

The Institutional Animal Care and Use Committee of the National Health Research Institutes in Taiwan approved all animal protocols.
1. Induction of Diabetic Model in Male Adult Sprague - Dawley (SD) Rats
<ol>
	<li>Remove rat food pellets from the cage to fast male SD rats (300 - 350 g) for 6 h prior to STZ induction.</li>
	<li>Prepare sodium citrate buffer (0.1 M, pH 4.5).
	<ol>
		<li>Dissolve 1.05 g citric acid monohydrate (C6H8O7 &#183; H2O; mol. wt. 210.14) in 50 mL distilled water to make a 0.1 M citric acid solution.</li>
		<li>Dissolve 1.47 g trisodium citrate dihydrate (C8H5O7Na3 &#183; 2H2O; mol. wt. 294.12) in 50 mL distilled water to make a 0.1 M sodium citrate solution.</li>
		<li>Add 25 mL citric acid solution to 25 mL sodium citrate solution. Monitor the sodium citrate buffer pH (pH 4.5) using a pH meter. 
		NOTE: The buffer is made isotonic by addition of an appropriate volume of 0.1 M sodium citrate solution.</li>
	</ol>
	</li>
	<li>Dissolve STZ in 0.1 M sodium citrate buffer to yield a 50 mg/mL STZ solution. 
	NOTE: The STZ solution is light sensitive, therefore, cover the STZ solution with aluminum foil and use within 15 - 20 min.</li>
	<li>Draw the 50 mg/kg STZ solution into a 1 mL insulin or tuberculin syringe with 26- to 28-gauge needle.&#160;Clean the injection site with an ethanol pad and intraperitoneally inject the STZ solution into the lower right quadrant of the abdomen to avoid damaging abdominal organs. &#160;</li>
	<li>Supply rats with 10% sucrose water as the sole water source for 48 h after STZ injection to prevent hypoglycemia.</li>
</ol>
2. Confirmation of Diabetes in STZ-induced Rats
<ol>
	<li>Monitor the fasting plasma glucose concentration of all rats injected by STZ post 72 h with a glucose meter.
	<ol>
		<li>Fast the STZ-induced diabetic rats for 15 h before measuring the fasting blood glucose level.</li>
		<li>Restrain the rats in a restraint bag and expose the tails for blood collection during the blood glucose measurements.</li>
		<li>Use a blood lancet to prick the tip of the tail to obtain a small drop of blood. Place the drop of blood on a glucose test strip. Record the fasting plasma glucose levels. 
		NOTE: The glucose meter detects and displays the blood glucose level in units of mg/dL. Exclude the rats with fasting blood glucose levels below 150 mg/dL after 2 weeks of STZ-induction.</li>
	</ol>
	</li>
</ol>
3. Evaluation of Peripheral Diabetic Neuropathy in Diabetic Rats
<ol>
	<li>Assess the mechanical allodynia with electronic von Frey.
	<ol>
		<li>Habituate the STZ-induced diabetic rats in a cage on a 1 cm diameter metal mesh floor for 30 min before evaluating the hind paw withdrawal response.</li>
		<li>Use an electronic von Frey probe with rigid tip (0.8 mm in diameter) to manually apply pressure to the plantar surface of the hind paw of the rats, and gradually increase the pressure until a paw withdrawal response is seen.</li>
		<li>Record the pressure that shows on the system and repeat the measurement 5 times per rat, with a 30 s interval between each measurement.</li>
	</ol>
	</li>
	<li>Assess the heat hyperalgesia with a hot plate.
	<ol>
		<li>Habituate the STZ-induced diabetic rats on the hot plate (24 &#177; 0.5 &#176;C) for 10 min before evaluating the pain response.</li>
		<li>Remove and place the rats back into their cages after habituation, heat the hot plate and maintain the hot plate&#39;s temperature at 55 &#177; 0.5 &#176;C.</li>
		<li>Place the rat on the heated hot plate while simultaneously starting the timer.</li>
		<li>When the rat exhibits distinct behaviors, such as licking the hind paw or abnormally flicking the hind paw, stop the timer, and record the withdrawal latency. 
		NOTE: If a rat does not express distinct behaviors after 20 s (20 s cut-off time), terminate the hot plate test and remove the rat from the hot plate.</li>
	</ol>
	</li>
</ol>
4. In Vivo Nerve Conduction Blockage with the HIFU Transducer
NOTE: The in vivo experiment starts on week 5 after 50 mg/kg STZ injection.
<ol>
	<li>Perform animal procedures before blocking of the CMAPs with HIFU sonication.
	<ol>
		<li>Sterilize the surgical tools (scalpel, scissors, forceps, and glass hook) in an autoclave before the surgery.</li>
		<li>Anesthetize the rats with intraperitoneal injection of tiletamine/zolazepam mixture (40 mg/kg) and xylazine (10 mg/kg) or via inhalation of 1.75% of isoflurane via isoflurane vaporizer. Place the rats on a heating pad to maintain the body temperature.</li>
		<li>Position the rats for surgery in ventral recumbency. Apply the eye ointment. Extend the leg of the rat and pinch the plantar surface of the foot with fingernails to ascertain the depth of anesthesia. If the rats show withdrawal responses, apply additional anesthesia.</li>
		<li>Remove hair from the thigh and lower back of the rats with an electric clipper. Apply liquid iodine with clean gauze at the surgical site and circularly move the gauze to the outward of the surgical site. Use an alcohol pad to wipe the liquid iodine with the same circular movement. This experiment is performed on the left and right surgical site. Repeat the procedure at the other surgical site when perform the next step of procedure.</li>
		<li>Use a sterile surgical scissors or scalpel to make an incision of the skin at the dorsal thigh. Use blunt surgical scissors to carefully separate the tissue underneath the skin and secure the skin with skin hooks.&#160;The femur can be seen within the muscles.</li>
		<li>Use the scissors to carefully separate the muscles parallel to femur until the mid-thigh sciatic nerve fibers that are embedded in the muscles are visible. Carefully use a glass hook to separate the mid-thigh sciatic nerve from the surrounding connective tissues and muscles.</li>
	</ol>
	</li>
	<li>Position the sciatic nerve in the HIFU focal zone using a custom-made nerve fixator (Figure 1 and Figure 3). 
	NOTE: The custom-made nerve fixator consists of 3 components (Figure 3). All the components are made of transparent polymethylmethacrylate (PMMA). The external thread of the top structure of component I is 2.5 mm tall and M10XP0.7 (Figure 4A). The central well is a 4.0 mm-diameter hole through component I. The bottom opening of the well is sealed by a sheet of tape. The diameter of the slot is 1.2 mm and the distance between the central plane of the slot and the top surface of component I is 3.1 mm. Component II consists of a main body, four legs and the bottom structure (Figure 4B). The internal thread of the bottom structure is 2.5 mm tall and M10XP0.7 to fit the external thread of component I. The diameter of the central hole is the same as the central well of component I. The dimensions of the main body are 32 mm in diameter and 5.4 mm in thickness. Four legs are symmetrically deployed. Two identical short legs are designed for alignment and two identical long legs work for hooking on component III. The outer diameter and height of component III are 41 mm and 9.2 mm. The internal thread is M36XP1.0 and the through hole is 27.5 mm in diameter (Figure 4C). The cone is a hollow taper with the top opening of 84 mm in diameter and the bottom opening of 27.5 mm in diameter. The height is 57.5 mm (Figure 5A).
	<ol>
		<li>Before the experiment, soak the custom-made acrylic nerve fixator in bleach-solution for 30 - 60 min followed by soaking in sterile water.</li>
		<li>Using a glass hook, lift the nerve carefully and put it in the slot of component I.</li>
		<li>Screw component II to component I. Fill the central well of component I with Ringer&#39;s solution for ultrasonic propagation and nerve preservation.</li>
		<li>Screw component III to the HIFU housing cone. Dock component III with component II through the four legs of component II. 
		NOTE: The geometric center of three components and the transducer are aligned. The distance between the nerve and the transducer is equal to the focal length, which ensures the nerve is inside the HIFU focal zone.</li>
	</ol>
	</li>
	<li>Insert one pair of acupuncture needles into the origin of the sciatic nerve and the other pair into the gastrocnemius muscle. Connect each pair of needles to the electrophysiology acquisition system through an electrical coaxial cable (Figure 1). 
	NOTE: On one end of the cable are two alligator clips to clip two needles separately and on the other end of the cable is a BNC connector to link the system. The pairs of acupuncture needles work as stimulating electrodes at the sciatic nerve and the recording electrodes at the gastrocnemius muscle.
	<ol>
		<li>Set the sampling rate and bandwidth of the electrophysiology acquisition system to 50 kHz and 70 Hz-3 kHz, respectively. Apply a supra-maximal stimulus with a pulse width of 0.1 ms to the stimulating electrodes at the origin of the sciatic nerve.</li>
		<li>Record the CMAPs from the recording electrodes and amplify the CMAPs with the built-in amplifier in the electrophysiology acquisition system. 
		NOTE: Use the built-in amplifier in the electrophysiology acquisition system to amplify the nerve signals and record the CMAPs from the recording electrodes with the electrophysiology acquisition system.</li>
	</ol>
	</li>
	<li>Use a commercial 2.68 MHz HIFU transducer to suppress the CMAPs in diabetic neuropathic rats. 
	NOTE: The specifications of the transducer are described as follows: a single-element spherical bowl with aperture diameter of 6 cm and focal length of 5 cm, and an ellipsoid focal zone of 4 mm in depth and 0.8 mm in width in the free field.
	<ol>
		<li>Immerse the spherical cone, the HIFU transducer and the cone cover in the tank filled with degassed water. Put the HIFU transducer into the spherical cone and fix the cone cover to the top opening of the spherical cone by 6 head screws (Figure 5B). After bubbles in the spherical cone are expelled naturally due to the low density of bubbles compared with water, seal the front-end opening of the cone by a transparent 0.03 mm thick tape. Screw component III onto the spherical cone.</li>
		<li>Take out the HIFU transducer with the spherical cone and component III from the degassed water tank. 
		NOTE: The reverse osmosis water used in the study is the water purified by the process of reverse osmosis. The reverse osmosis water is boiled to expel the gas. After cooling, the degassed water is obtained in an individual sealed tank.</li>
	</ol>
	</li>
	<li>Put component I into the space between the nerve and the muscle carefully, and position the nerve in the gap of component I. Perform steps 4.2.3 and 4.2.4 to ensure that the nerve is inside the focal zone of the HIFU (Figure 3A).</li>
	<li>Link a function generator and a radiofrequency power amplifier. Connect the power amplifier to the HIFU transducer for generation of the HIFU beam. Manually set the voltage output of the function generator to the HIFU transducer via the power amplifier. Manually turn off the function generator once the HIFU-exposure time is up. Observe time using a timer. 
	NOTE: The intensity and energy of HIFU beam used in this study are 2,810 W/cm2 and 84 J/mm2, respectively.</li>
	<li>Simultaneously, deliver the stimulus via the electrophysiology acquisition system (step 4.3) and HIFU beam via HIFU system (step 4.6) to the sciatic nerve while recording the CMAPs. Gradually increase the HIFU exposure on the sciatic nerve from 3 s, 5 s to 8 s until decrease or inhibition of the amplitude of CMAPs is observed.
	<ol>
		<li>Record the CMAPs once per second during the delivery of the HIFU beam. After observing the change in the amplitude of CMAPs, turn off the HIFU system and manually click on the record icon on the electrophysiology acquisition software to record CMAPs every 2 min in the early 10 min, every 5 min in the consecutive 30 min, and every 10 min in the last phase until the recording time reaches 2 h.</li>
	</ol>
	</li>
	<li>Separate component II and III of the nerve fixator (Figure 3) to remove the HIFU transducer from the incision site. Separate component II and I to release the secured sciatic nerve. Suture the surgical site of the diabetic rat by 4-0 chromic catgut sutures after recording the CMAPs. Apply liquid iodine to the surgical site to prevent infection.
	<ol>
		<li>Place the cages on the heating pad and allow the rats to recover in their cages before returning them to the animal facility. Provide the rats with ibuprofen in drinking water for 3 days or intraperitoneal injection of buprenorphine (0.05 - 0.1 mg/kg).</li>
	</ol>
	</li>
	<li>Insert stimulating and recording electrodes in the origin of the sciatic nerve and the gastrocnemius muscles of anesthetized diabetic neuropathic rats as described in steps 4.1.2 and 4.3 on days 7, 14, and 28 after the initial HIFU sonication. Repeat steps 4.3.1 to 4.3.2.
	<ol>
		<li>Place the cages on the heating pad and allow the rats to recover in their cages before moving the cages to the animal facility.</li>
	</ol>
	</li>
	<li>Euthanize the rats after the experiment. Place the rat in a carbon dioxide chamber. Wait about 5 min for the rats to stop breathing. Ensure that the heart has stopped beating.</li>
</ol>

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<li>Lele, P. P. <a target="_blank" href="http://www.sciencedirect.com/science/article/pii/0014488663900086">Effects of focused ultrasonic radiation on peripheral nerve, with observations on local heating.</a> Exp Neurol. 8 (1), 47-83 (1963).</li>
<li>Hong, C. Z. <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/1846738">Reversible nerve conduction block in patients with poly- neuropathy after ultrasound thermotherapy at therapeutic dosage.</a> Arch Phys Med Rehabil. 72 (2), 132-137 (1991).</li>
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The authors have nothing to disclose.

Partial and temporary suppression of action potentials of the neuropathic nerves from diabetic rats in vivo and instant occurrence of the blocking effect after HIFU treatment both were observed. The 28-day follow-up study on CMAPs demonstrated that a safe blockade of the nerve conduction could be carried out at an appropriate HIFU exposure. As a result, the above protocol of the HIFU treatment can provide an alternative solution for the reversible conduction block of sciatic nerves in diabetic rats.
<p class...

Oral medications, acupuncture1, and electrical nerve stimulation2 have been used for the treatment of painful diabetic polyneuropathy. However, the side effects of the oral medications, invasive operation of acupuncture, and electrical nerve stimulation hamper the therapeutic efficacy and patient&#39;s adherence. Ultrasound block of peripheral nerves in animal models has been investigated for decades3,4,5. The conduction of in vitro sciatic nerves of the large green frog was inhibited reversibly after the treatment of 10 - 20 pulses of ultrasound exposure for 0.4 - 1.0 s6. One factor to block nerve conduction is the temperature rise induced by ultrasound7. For patients with polyneuropathy, the suppression of compound muscle action potentials (CMAPs) was performed in the peroneal nerve exposed to low-intensity ultrasound for 2 min8. The full recovery time was within 5 min.
Recently, the Food and Drug Administration of the United States approved HIFU as a non-invasive treatment for uterine fibroid tumors9, pain palliations of bone metastases10, and prostate cancer11. An HIFU transducer emits acoustic beams outside the body, and the beams transmit in various tissue mediums and converge on the target tumor at the focus. The focal zone is immediately formed to generate localized effects on target tumors without damaging the surrounding tissues. HIFU has also been applied to inhibit nerve conduction or cause nerve denervation in in vivo experiments of normal Sprague-Dawley (SD) rats12. In addition, the short-term and long-term effects of HIFU on neuropathic nerves have been investigated13. Previous outcomes demonstrated that the reversible or permanent block of sensory nerve conduction could be achieved by HIFU with appropriate parameters. Besides analgesic applications, HIFU might be used as a tool to investigate the relative contribution of peripheral and central components to nerve conduction blockade for basic research of neurology and development of pain medication. Therefore, a HIFU blocking technology platform specific for peripheral nerves in animal models is needed. The purpose of this article is to demonstrate the procedures for partially or completely blocking the action potentials of peripheral nerves in diabetic neuropathic rats by HIFU. Diabetic rat models and evaluation of peripheral neuropathic symptoms were established. An HIFU platform and experimental processes specific for treating rat sciatic nerves are presented.

<table><tbody><tr><td>streptozotocin</td><td>Sigma</td><td>85882</td><td></td></tr><tr><td>citric acid monohydrate&amp;nbsp;</td><td>Sigma</td><td>C1909</td><td></td></tr><tr><td>trisodium citrate dihydrate</td><td>Sigma</td><td>W302600</td><td></td></tr><tr><td>glucose meters</td><td>Roche Accu-Check Active</td><td>GC</td><td></td></tr><tr><td>electronic von Frey device</td><td>IITC Life Science</td><td>2390</td><td></td></tr><tr><td>hot plate</td><td>IITC Life Science</td><td></td><td></td></tr><tr><td>Biopac MP36 acquisition system</td><td>Biopac Systems, Inc.</td><td></td><td></td></tr><tr><td>HIFU transducer</td><td>Sonic Concepts</td><td>H108</td><td></td></tr><tr><td>function generator</td><td>Agilent</td><td>33250A</td><td></td></tr><tr><td>power amplifier</td><td>Electronics &amp;amp; Innovation</td><td>1040L</td><td></td></tr><tr><td>Rats&amp;nbsp;</td><td>Biolasco taiwan</td><td>Sprague-Dawley</td><td></td></tr><tr><td>Puralube vet ointment</td><td>Dechra</td><td></td><td></td></tr><tr><td>isoflurane vaporizer</td><td>Parkland Scientific</td><td>V3000PS</td><td></td></tr><tr><td>Isoflurance</td><td>Attane</td><td></td><td></td></tr><tr><td>Restraint bag (Decapicones)</td><td>Braintree Scientific</td><td>DC 200</td><td></td></tr></tbody></table>

an ultrasonic tool for nerve conduction block in diabetic rat models

An Ultrasonic Tool for Nerve Conduction Block in Diabetic Rat Models

Nerve conduction block with a high intensity-focused ultrasound (HIFU) transducer has been performed in normal and diabetic animal models recently. HIFU can reversibly block the conduction of peripheral nerves without damaging the nerves while using an appropriate ultrasonic parameter. Temporary and partial block of the action potentials of nerves shows that HIFU has the potential to be a useful clinical treatment for pain relief. This work demonstrates the procedures for suppressing the action potentials of neuropathic nerves in diabetic rats in vivo using an HIFU transducer. The first step is to generate adult male diabetic neuropathic rats by streptozotocin (STZ) injection. The second step is to evaluate the peripheral diabetic neuropathy in STZ-induced diabetic rats by an electronic von Frey probe and a hot plate. The final step is to record in vivo extracellular action potentials of the nerve exposed to HIFU sonication. The method showed here may benefit the study of ultrasound analgesic applications.

The in vivo study demonstrated that, with an HIFU dose of 3 s sonication at an intensity of 2,810 W/cm2, the CMAPs were suppressed by 20% of baseline, but they were completely recovered after 30 min (Figure 2A, diamonds) and were almost constant in the period of 28 days (Figure 2B, diamonds). For the 5 s HIFU exposure at the same intensity, the CMAPs decreased to 65.4% (9.5%) of baseline at 4 min and recovered...

This work presents the methodology of applying high intensity-focused ultrasound to block the action potentials of diabetic neuropathic nerves.

Nerve conduction block with a high intensity-focused ultrasound (HIFU) transducer has been performed in normal and diabetic animal models recently. HIFU ...

The overall goal of this ultrasound technique is to perform temporary block of peripheral nerve conduction using an ultrasound thermal effect. This method can help answer key questions in the pain management field such as analgesia of diabetic peripheral neuropathy. The main advantage of this technique is that ultrasound exposure on the target nerve is localized and repeatable.The implications of this technique is tended toward analgesia of human neuropathic pain because ultrasound treatment is a long, very safe process. Demonstrating the procedure will be Cheng Jung-Sung and Tan Joo-Shin plus research assistants from a laboratory. After fasting male Sprague-Dawley or SD rats and preparing STZ solution according to the text protocol, use a 26 or 28 gauge needle to draw the 50 milligram per kilogram STZ solution into a one milliliter insulin or tuberculin syringe.Use an ethanol pad to clean the injection site on the rats and inject the STZ solution into the animal's abdomen. At 72 hours post-injection, measure the fasting plasma glucose concentration of all rats injected by using a blood lancet to prick the tip of the tail to obtain a small drop of blood. Place the drop of blood on a glucose test strip and insert it into a glucose meter before recording the fasting plasma glucose levels.To habituate a STZ-induced diabetic rat, transfer it to a cage on a one centimeter diameter metal mesh floor for 30 minutes. Then, to evaluate the hind paw withdrawal response, use an electronic Von Frey Probe with a rigid tip to manually apply pressure to the plantar surface of the hind paw of the rats and gradually increase the pressure until a paw withdrawal response is seen. Record the pressure and wait 30 seconds before repeating the measurement again.Five weeks after STZ injection, after anesthetizing the rats and performing a pinch of the plantar surface of the foot according to the text protocol, use an electric clipper to remove the hair from the thigh and lower back. Apply liquid iodine to the skin on the surgical site. Then use an alcohol pad to wipe off the liquid iodine.With a sterile scalpel, make an incision of the skin at the dorsal thigh. Use surgical scissors to spread the tissue underneath the skin and use skin hooks to secure the skin. With the scissors, carefully separate the muscles parallel to the femur until the mid-thigh sciatic nerve fibers embedded in the muscles are visible.Carefully use a glass hook to separate the mid-thigh sciatic nerve from the surrounding connective tissue and muscles. Then, to position the sciatic nerve in the high-intensity focused ultrasound, or HIFU focal zone, using a custom-made nerve fixator, use a glass hook to carefully lift the nerve and put it in the slot of component one of the device. Next, screw component two to component one.Then use Ringer's Solution to fill the central well of component one for ultrasonic propagation and nerve preservation. Screw component three to the HIFU housing cone. Then through the four legs of component two, dock component three with component two.After inserting one pair of acupuncture needles into the origin of the sciatic nerve and the other pair into the gastrocnemius muscle, connect each pair of needles to the electrophysiology acquisition system through an electrical coaxial cable. Set the sampling rate and bandwidth of the electrophysiology acquisition system to 50 kilohertz and 70 hertz three kilohertz, respectively. Then at the origin of the sciatic nerve, apply a supramaximal stimulus with a pulse width of 0.1 milliseconds to the stimulating electrodes.In the electrophysiology acquisition system, record the compound muscle action potentials or CMAPs from the recording electrodes and amplify the CMAPs with the built-in amplifier. To use a commercial 2.68 millihertz HIFU transducer to suppress the CMAPs in diabetic neuropathic rats, immerse the spherical cone, the HIFU transducer and the cone cover in the tank filled with degassed water. Put the HIFU transducer into the spherical cone and use six head screws to fix the cone cover to the top opening of the spherical cone.After the bubbles in the spherical cone are expelled naturally due to the low density of the bubbles compared to the water, use transparent 0.03 millimeter thick tape to seal the front end opening of the cone. Then screw component three onto the spherical cone and remove the HIFU transducer with the spherical cone and component three from the degassed water tank. Carefully insert component one into the space between the nerve and the muscle and position the nerve in the gap of component one.To ensure that the nerve is inside the focal of the HIFU as demonstrated earlier, screw component two to component one. After screwing component three to the HIFU housing cone, through the four legs of component two, dock component three with component two and use Ringer's Solution to fill the central well of component one for ultrasonic propagation and nerve preservation. Link a Function Generator and a radio-frequency power amplifier.Connect the power amplifier to the HIFU transducer for generation of the HIFU beam. Then manually set the voltage output of the Function Generator to the HIFU transducer via the power the power amplifier and set a timer to measure HIFU exposure time. Manually turn off the Function Generator once the HIFU exposure time is up.Simultaneously deliver the stimulus via the electrophysiology acquisition system and HIFU beam via the HIFU system to the sciatic nerve while recording the CMAPs. Gradually increase the HIFU exposure on the sciatic nerve from three seconds, five seconds, then to eight seconds, until a decrease or inhibition of the amplitude of CMAPs is observed. Record the CMAPs once per second during the delivery of the HIFU beam.After observing the change in the amplitude of CMAPs, turn off the HIFU system and manually click on the Record icon on the electrophysiology acquisition software to record CMAPs for two hours. After removing the nerve fixator components, suturing the surgical site of the diabetic rat, and allowing the rats to recover, on days seven, 14 and 28 after the initial HIFU sonication, insert stimulating and recording electrodes in the anesthetized diabetic neuropathic rats as before and record additional CMAPs as demonstrated earlier in this video. The in vivo study demonstrated in this video showed that with a high-intensity focused ultrasound, or HIFU dose of three seconds of sonication at an intensity of 2810 watts per square centimeter, the CMAPs were suppressed by 20 per cent of baseline but they were completely recovered after 30 minutes.For the five second HIFU exposure at the same intensity, the CMAPs decreased to 65.4 per cent of baseline at four minutes and recovered to 73.7 per cent of baseline by 120 minutes. The CMAPs did not return to baseline levels until day 14. When HIFU sonication time was increased to 8 seconds under the same intensity, the CMAPs were reduced to 26 per cent of baseline at four minutes but increased to 38 per cent of baseline at 120 minutes and gradually increased to 74 per cent of baseline by day 28.Once mastered, this technique can be done in one hour if it is performed properly. While attempting this procedure, it's important to remember to treat the nerve very carefully. Following this procedure, other methods like brand easy detection can be performed in order to answer additional questions like peripheral sensoral interaction.After its development, this technique paved the way for researchers in the field of pain management to explore a new energistic modality for accupain in peripheral neuropathy. After watching this video, you should have a good understanding of how to graph the conduction of diabetic neuropathic nerves in a rat model by ultrasound. Don't forget that working with the power amplifier can be extremely hazardous and the precautions such as wearing insulating work gloves should always be taken while performing this procedure.

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Research

JoVE Journal

Bioengineering

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Source: Lee, Y. F., et al. An Ultrasonic Tool for Nerve Conduction Block in Diabetic Rat Models. J. Vis. Exp. (2017)This video demonstrates the use of high-intensity focused ultrasound (HIFU) to block action potentials from the sciatic nerve to the gastrocnemius muscle in a diabetic rat model. Upon delivering the HIFU beam to the nerve, a decrease in muscle signal confirms HIFU's potential as a non-invasive therapy for diabetic neuropathic pain relief.

High-Intensity Focused Ultrasound for Blocking Nerve Action Potentials in a Diabetic Rat Model 

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Learn high intensity-focused ultrasound for temporary nerve conduction block in diabetic neuropathy using Sprague-Dawley rats. This localized method offers a safe, repeatable approach to analgesia research.

An Ultrasonic Tool for Nerve Conduction Block in Diabetic Rat Models

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