Observation of the Systolic Function of Isolated Right Atria from Guinea Pigs

Summary

The present protocol describes an efficient method for screening drugs that enhance myocardial contractility using isolated right atria from guinea pigs.

Abstract

Common chronic heart failure (CHF) is characterized by impaired ventricular filling and/or ejection function, which leads to insatiable cardiac output and increased incidence. The decline in cardiac systolic function is a key factor in the pathogenesis of CHF. Systolic function is simply the filling of oxygenated blood in the left ventricle, followed by the blood being pumped throughout the body during a heartbeat. A weak heart and the inability of the left ventricle to contract appropriately as the heart beats indicate poor systolic function. Many traditional herbs have been suggested to strengthen the systolic function of the heart in patients. However, stable and efficient experimental methods for screening compounds that enhance myocardial contractility are still lacking in the process of ethnic medicine research. Here, taking digoxin as an example, a systematic and standardized protocol is provided for screening compounds that enhance myocardial contractility by using isolated right atria from guinea pigs. The results showed that digoxin could markedly enhance the contractility of the right atrium. This systematic and standardized protocol is intended to serve as a methodological reference for screening the active ingredients of ethnic medicines in the treatment of CHF.

Introduction

Heart failure is caused by myocardial infarction, myocardiopathy, hemodynamic overload, inflammation, and other causes of myocardial injuries, which modify the myocardial anatomy and activity and, ultimately, lead to failure in the ventricular pumping or filling. Palpitations, tiredness, and fluid retention are the main primary clinical symptoms¹. CHF is a chronic heart failure condition that can be maintained, deteriorate, or show decompensation over time, and its incidence and prevalence increase with age². The decline in cardiac systolic function is a key factor in the pathogenesis of CHF³. The....

Protocol

The experimental protocol was conducted in accordance with the requirements of the Use of Laboratory Animals and Institutional Animal Care and Use Committee at Ningxia Medical University. Male Dunkin-Hartley guinea pigs weighing 300-450 g were used for the present study. The effect of digoxin on contractility was observed in isolated right atria from the guinea pigs (Figure 2).

1. Oxygenation preparation for the isolated right atria of guinea pigs

1. Prepare the experimental instruments, including a biological signal acquisition and processing system, a JH-2 muscle force transducer, a ....

Results

A decrease in myocardial contractility causes insufficient cardiac output, which leads to CHF (Figure 1). This protocol allowed the recording of the effects of different drugs on the systolic function of isolated right atria from guinea pigs and then the rapid screening of compounds from ethnic drugs that enhance myocardial contractility. After connecting the right atrium, the JH-2 muscle force transducer, and the biological signal acquisition and processing system in steps, the parameters w.......

Discussion

The normal rhythmic activity of the heart requires a suitable physical and chemical environment, as does the activity of isolated right atria. Isolated right atria are isolated from the innervation of the body and the direct influence of systemic humoral factors, meaning changes in the activity of the right atria when changing the drugs they are exposed to can be observed. The fundamental causes of bioelectrical activity in excitable cells are changes in the ion permeability of the cell membrane and the subsequent diffus.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
4-0 surgical suture	Yangzhou Fuda Medical Devices Co., Ltd
5% Digoxin (soluble in dimethyl sulfoxide)	TCI Shanghai	D1828	CAS: 20830-75-5; Purity: >96.0%
BL-420N biological signal acquisition and processing system	Chengdu Tai Meng Software Co., Ltd	1700142S
CaCl2	Shanghai yuanye Bio-Technology Co., Ltd	S24110	CAS: 10043-52-4; Purity: 96%
Glucose	Shanghai yuanye Bio-Technology Co., Ltd	S11022	CAS: 50-99-7; Purity: 99%
Isoflurane	RWD Life Science Co., Ltd	R510-22-16
JH-2 muscle force transducer	Institute of Aerospace Medical Engineering, Beijing, China
KCl	Shanghai yuanye Bio-Technology Co., Ltd	S24120	CAS: 7447-40-7; Purity: 99.5%
Magnus bath	Shanghai Future Experimental Equipment Co., Ltd	L046525
MgSO4	Shanghai yuanye Bio-Technology Co., Ltd	S24253	CAS: 7487-88-9; Purity: 98%
NaCl	Shanghai yuanye Bio-Technology Co., Ltd	S24119	CAS: 7647-14-5; Purity: 99.5%
NaH2PO4	Shanghai yuanye Bio-Technology Co., Ltd	S24161	CAS: 7558-80-7; Purity: 99%
NaHCO3	Shanghai yuanye Bio-Technology Co., Ltd	S24153	CAS: 144-55-8; Purity: 99.8%
Operating basin	Guangzhou Telekuan Medical Instrument Co., Ltd		305 mm x 230 mm
Ophthalmic forcep	Suzhou Shuanglu Medical Instrument Co., Ltd
Ophthalmic operating scissor	Suzhou Shuanglu Medical Instrument Co., Ltd
Paraffin	Leica Biosystems	39601095
Petri dish	Corning	430167	100 mm x 20 mm
Rodent anesthesia machine	Shanghai Yuyan Instruments Co., Ltd		ABS type (single channel)
Scale	Shanghai Yueping Scientific Instrument Co., Ltd	YP1002
Surgical plate	Zhengzhou Ketai Experiment Equipment Co., Ltd		21 cm x 31 cm
Tissue scissor	Suzhou Shuanglu Medical Instrument Co., Ltd	SL0023