An Innovative Running Wheel-based Mechanism for Improved Rat Training Performance

Summary

This study presents an innovative running wheel-based animal mobility system to quantify an effective exercise activity in rats. A rat-friendly testbed is built, using a predefined adaptive acceleration curve, and a high correlation between the effective exercise rate and the infarct volume suggests the protocol's potential for stroke prevention experiments.

Abstract

This study presents an animal mobility system, equipped with a positioning running wheel (PRW), as a way to quantify the efficacy of an exercise activity for reducing the severity of the effects of the stroke in rats. This system provides more effective animal exercise training than commercially available systems such as treadmills and motorized running wheels (MRWs). In contrast to an MRW that can only achieve speeds below 20 m/min, rats are permitted to run at a stable speed of 30 m/min on a more spacious and high-density rubber running track supported by a 15 cm wide acrylic wheel with a diameter of 55 cm in this work. Using a predefined adaptive acceleration curve, the system not only reduces the operator error but also trains the rats to run persistently until a specified intensity is reached. As a way to evaluate the exercise effectiveness, real-time position of a rat is detected by four pairs of infrared sensors deployed on the running wheel. Once an adaptive acceleration curve is initiated using a microcontroller, the data obtained by the infrared sensors are automatically recorded and analyzed in a computer. For comparison purposes, 3 week training is conducted on rats using a treadmill, an MRW and a PRW. After surgically inducing middle cerebral artery occlusion (MCAo), modified neurological severity scores (mNSS) and an inclined plane test were conducted to assess the neurological damages to the rats. PRW is experimentally validated as the most effective among such animal mobility systems. Furthermore, an exercise effectiveness measure, based on rat position analysis, showed that there is a high negative correlation between the effective exercise and the infarct volume, and can be employed to quantify a rat training in any type of brain damage reduction experiments.

Introduction

Strokes exist continuously as a financial burden to countries globally, leaving countless patients physically and mentally disabled^1,2. There is clinical evidence to suggest that regular exercise can improve nerve regeneration and strengthen neural connections^3,4, and it is also shown that exercise can decrease the risk of suffering ischemic strokes⁵. With either a treadmill or a running wheel as an exercise training system, rodents, such as rats, serve as a proxy for humans for testing the effectiveness of exercises in a vast majority of clinical experiments^6-8

Protocol

Ethics Statement: The experimental procedures were approved by the animal ethics committee of Southern Taiwan University of Science and Technology Laboratory Animal Center, National Science Council, Republic of China (Tainan, Taiwan).

1. Constructing the Running Wheel Structure

NOTE: All acrylic should be transparent. Wash the disassembled wheel with water, then use alcohol to wipe the rubber track and acrylic sheets after each use.  

1. Obtain an acrylic running wheel to be 55 cm in diameter and 15 cm in width.
   NOTE: This wheel is larger than a traditional running wheel (di....

Results

This section is devoted to comparisons, made 1 week after surgery, on the mNSS scores, incline plane test results and brain infarct volumes among five groups. Figure 4A and 4B present the average mNSS scores and the average of incline plane test results, respectively. The PRW group appears as the best in terms of mNSS improvement. The significant differences between PRW and MRW and between treadmill and PRW clearly suggest that the PRW protects against st.......

Discussion

This protocol describes a highly effective running wheel system for reducing the severity of the effects of the stroke in animals. As a rat-friendly testbed, this platform is designed as well in such a way that a stable running speed can be maintained by rats throughout a running process by means of a predetermined adaptive acceleration curve. In typical training systems, preset training speeds and durations are set manually. Once an exercise commences, a preset speed is reached very shortly. In this context, i.......

Materials

Name	Company	Catalog Number	Comments
Brushless DC motor	Oriental Motor	BLEM512-GFS
Motor driver	Oriental Motor	BLED12A
Motor reducer	Oriental Motor	GFS5G20
Speedometer	Oriental Motor	OPX-2A
Treadmill	Columbus Instruments	Exer-6M
Infrared transmitter	Seeed Studio	TSAL6200
Infrared Receiver	Seeed Studio	TSOP382
Microcontroller	Silicon Labs	C8051F330
CCD camera	Canon Inc.	EOS 450D
Image processing software	Adobe Systems Incorporated	ADOBE Photoshop CS5 12.0
Image analysis	Media Cybernetics	Pro Plus 4.50.29
Sodium pentobarbital	Sigma-Aldrich (Saint Louis, MO, USA)	SIGMA P-3761
Ketamine	Pfizer (Kent, UK)	1867-66-9
Atropine	Taiwan Biotech Co., Ltd. (Taoyuan, Taiwan)	A03BA01
Xylazine	Sigma-Aldrich (Saint Louis, MO, USA)	SIGMA X1126
Buprenorphine	Sigma-Aldrich (Saint Louis, MO, USA)	B9275
Anesthesia	Sigma Chemical