Blue Light Therapy for Drug-Resistant Bacterial Infections in Burn Wounds in a Mouse Model

Abstract

Source: Wang, Y., et al. In Vivo Investigation of Antimicrobial Blue Light Therapy for Multidrug-resistant Acinetobacter baumannii Burn Infections Using Bioluminescence Imaging. J. Vis. Exp. (2017)

This video demonstrates the procedure for treating burn wound infections caused by bioluminescent, drug-resistant bacteria in mice using blue light therapy, followed by bioluminescence imaging to monitor treatment efficacy.

Protocol

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.

1. Antimicrobial Blue Light Therapy for A. baumannii Infection in Mice

1. Anesthetize the mice with an intraperitoneal injection of a ketamine-xylazine cocktail (100 mg/kg - 20 mg/kg). An absence of the palpebral reflex suggests an appropriate anesthetic depth.
2. Randomly divide the mice into an aBL-treated group (n = 10) and an untreated control group (n = 10).
3. For the antimicrobial blue light (aBL)-treated group, cover the mice's eyes with aluminum foil to avoid overexposure to light. Place the mouse burns directly under the light-emitting diode (LED), with the lid of a 35-mm petri dish underneath the mouse abdomen to keep their backs horizontal.
4. Replace the power/energy meter mentioned in step 3.5 with a mouse on a square petri dish. Adjust the mouse's height back to a position where the distance between the LED aperture and the surface of the mouse burn is equal to that between the LED aperture and the level of the light sensor of the power/energy meter.
5. Irradiate the infected burns at an irradiance of 100 mW/cm². Deliver aBL in doses of 72 J/cm² until a total dose of 360 J/cm² is reached (e.g., 0, 72, 144, 216, 288, and 360 J/cm²). After each light dose, perform bioluminescence imaging for the mice.
6. For the untreated control group, perform bioluminescence imaging of the mouse burns, using the same time intervals as used for the aBL-treated group.
7. Before the recovery of the mice, place the mice on the water-heated surgical bed to prevent heat loss and hypothermia. Observe the activity and the palpebral reflex of the mice until recovery. After the recovery of the mice, house them 2-3 per cage.

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
IVIS	PerkinElmer Inc, Waltham, MA	IVIS Lumina Series III	Pre-clinical in vivo imaging
Light-emitting diode LED	VieLight Inc, Toronto, Canada	415 nm	Light source for illumination
Power/energy meter	Thorlabs, Inc., Newton, NJ	PM100D	Light irradiance detector
Mouse	Charles River Laboratories, Wilmington, MA	BALB/c	7-8 weeks age, 17-19 g weight
Acinetobacter baumannii	Brooke Army Medical Center, Fort Sam Houston, TX	Clinical isolate	Engineered luminescent strain
Phosphate Buffered Saline, 1x Solution	Fisher Scientific	BP24384	A standard phosphate buffer used in many biomolecular procedures
Fisher Scientific Redi-Tip Pipet Tips, 1-200 µL	Fisher Scientific	02-707-502	Pipet Tips
Brass Block	Small Parts, Inc., Miami, FL	10 mm by 10 mm	For creation of burns in mice
Extreme Dragon PBI/Kevlar High-Heat Gloves	Superior Glove Works Ltd, Cheektowaga, NY	PBI83514	Heat Resistant Gloves
Greiner dishes	Sigma-Aldrich Co. LLC	P5112-740EA	35 mm ×10 mm
Corning Digital Hot Plate	Cole-Parmer Instrument Company, LLC	UX-84301-65	10" x 10", 220 VAC, for boiling water
Mouse/Rat Thin Line Water Heated Surgical Bed	E-Z Systems	EZ-211	Prevents heat loss and hypothermia during surgery
Vet ointment	S&K Pharma, GmbH	Kerato Biciron 5%, Augensalbe	Opthalmic ointment to prevent eye dryness