A Middle Cerebral Artery Occlusion Technique for Inducing Post-stroke Depression in Rats

Summary

Here we present a protocol to induce post-stroke depression in rats by occluding the middle cerebral artery via the internal carotid artery. We use the Porsolt forced swim test and the sucrose preference test to confirm and evaluate induced depressive moods.

Abstract

Post-stroke depression (PSD) is the most recurrent of all psychiatric complications resulting from an ischemic stroke. A greater majority (about 60%) of all ischemic stroke patients suffer from PSD, a disorder considered to be an ischemic stroke-related precursor for increased death and degradation in health. The pathophysiology of PSD is still obscure. To study the mechanism of development and occurrence of PSD further, and to find out a therapy, we attempted to develop a new protocol that requires occluding the middle cerebral artery (MCA) via the internal carotid artery (ICA) in rats. This protocol describes a model of PSD induced in rats through the middle cerebral artery occlusion (MCAO). Also used in the experiment are the Porsolt forced swim test and the sucrose preference test to confirm and evaluate the depressive mood of the rats under investigation. Rather than inserting the catheter through the external carotid artery (ECA), as stipulated for the original procedure, this MCAO technique has the monofilament passing directly through the ICA. This MCAO technique was developed a few years ago and leads to a reduction in mortality and variability. It is generally accepted that the criteria used are preferred in the selection of biological models. The data obtained with this protocol show that this model of MCAO could be a way of inducing PSD in rats and could potentially lead to the understanding of the pathophysiology and the future development of new drugs and other neuroprotective agents.

Introduction

Stroke is fourth on the list of death-perpetrating diseases in the United States^1,2,3, while it causes the majority of disabilities in adults in developed countries⁴; this makes stroke a leading contender among the world's most significant health issues. Normalcy in stroke-surviving patients is rare, with about 15%-40% of survival victims suffering permanent disability, 20% requiring institutional care 3 months after stroke onset⁵, and about a third of 6-month survivals needing others to help them live through each day

Protocol

The Animal Care Committee of the Ben-Gurion University of the Negev, Israel approved all treatment and testing procedures used in this protocol.

1. Preparation of Rats for the Experimental Procedure

NOTE: Select adult male Sprague-Dawley rats weighing 300-350 g.

1. House the rats, four per cage, in a vivarium at 22 °C and 40% humidity, with a reversed 12 h light/dark cycle (lights off at 8:00 a.m.) and unlimited access to food and water.
2. Randomly assign the rats to two groups, namely an MCAO group (N = 24) and a Sham group (N = 19).

Results

Histological findings (Table 1) revealed a statistically significant infarct volume as a percentage of total brain (p < 0.0001) post-MCAO when compared to animals in the sham-control group. Also reported was a statistically significant brain edema when the evaluation from the experimental group (p < 0.0003) was put side by side with that of the sham-control group.

The NSS scores obtained,.......

Discussion

One of the ways in which the MCAO technique presented here could be deemed safer than the original MCAO model is illustrated by the fact that the ECA and its branches, including the occipital artery, the terminal lingual, and the maxillary artery, are not compromised when occluding the MCA via the ICA. The original MCAO model's offset of the ECA (and its branches), by distally dissecting and coagulating them⁴⁶, causes impaired mastication, owing to a compromise to the vascular supply to mastic.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Absorbent pad	-	-	-
Black lusterless perspex box	-	-	(120 cm × 60 cm × 60 cm), divided into a 25% central zone and the surrounding border zone
Bottles	Techniplast	ACBT0262SU	150 mL bottles filled with 100 mL of water and 100 mL 1%(w/v) sucrose solution
Electric Shock	Heat System Ultasonic Inc.	-	-
Horizon-XL	Mennen Medical Ltd
Imaging System	Kodak	-	For imaging and quantification
Monofilament	-	-	-
Paper towels	Pharmacy	-	Dry towels used for keeping rats dry after immersing them in water
Pexiglass cylinder	-	-	a 100 cm tall and 40 cm in diameter cylinder used for carrying out the forced swim test
Purina Chow	Purina	5001	Rodent laboratory chow given to rats, mice and hamster is a life-cycle nutrition that has been used in biomedical researc for over 5 decades. Provided to rats ad libitum in this experiment
Rat Cages	Techniplast	2000P	Conventional housing for rodents. Was used for housing rats throughout the experiment
Scanner	Canon CanoScan	4200F	-
Video Camera	ETHO-VISION (Noldus)	-	Digital video camera for high definition recording of rat behavior under open field test