ABSTRACT
The aim of the present study was to investigate the differences of the pathological changes and cognitive function after bilateral common carotid artery occlusion (BCCAO) between Sprague-Dawley (SD) and Wistar rats. Male SD and Wistar rats were randomly divided into 2 groups, respectively: sham operated (S-sham and W-sham) and operated (S-BCCAO and W-BCCAO) groups. The survival rate and the rate of loss of pupillary light reflex (PLR) were observed on day 1, 3, 7, 14 and 28 after the operation, and the light-dark box, Y-maze and odor recognition tests were performed to detect cognitive function on day 28 after the operation. HE and Luxol fast blue staining were used to observe the pathological changes of gray matter (hippocampus), white matter (optical tract), optic nerve, and retina. The results showed that the survival rate of the W-BCCAO group was 62.5%, and PLR loss rate was 100%; whereas the survival rate of the S-BCCAO group was 100%, and PLR loss rate was 58.3%. In the W-BCCAO group, percentages of time spent and distance traveled in the light box were more than those in the W-sham group, but there was no statistical significance between the S-BCCAO and S-sham groups. In the S-BCCAO group, the percentages of time spent and distance traveled in the III arm (labyrinth arm) of the Y-maze were less than those in the S-sham group, but no statistical significance was found between the W-BCCAO group and W-sham group. In the S-BCCAO group, the discrimination ratio of the odor recognition task was less than that in the S-sham group, but no statistical significance could be seen between the W-BCCAO and W-sham groups. Ischemic injury was observed in the CA1 area of the hippocampus in the S-BCCAO group, but no readily visible damage was observed in the W-BCCAO group. Ischemic injury of the visual beam and optic nerve was observed in both the S-BCCAO and W-BCCAO groups. Compared with the corresponding sham groups, the S-BCCAO and W-BCCAO groups showed serious retinal damage with significant thinner retina. The ganglion cell layer (GCL), inner plexiform layer (IPL), and outer plexiform layer (OPL) were thinner in the S-BCCAO group, but no statistical significances were shown in the other layers. All the layers, except the outer nuclear layer (ONL), were significantly thinner in the W-BCCAO group. The results indicate that there are differences of the pathological changes in the hippocampus and visual conduction pathway after BCCAO between SD and Wistar rats, and the degree of learning and memory injury was also different, which suggests that the vascular dementia model of different rat strains should be selected according to research purpose.
Subject(s)
Animals , Male , Rats , Brain , Pathology , Carotid Artery Diseases , Pathology , Carotid Artery, Common , Pathology , Cognition , Disease Models, Animal , Rats, Sprague-Dawley , Rats, WistarABSTRACT
This work was performed to determine the role of delta-opioid receptor (DOR) in protection against acute ischemia/reperfusion injury. Transient (1 h) focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO). DOR agonist TAN-67 (30 nmol, 60 nmol, 200 nmol), DOR antagonist naltrindole (20 nmol, 50 nmol, 100 nmol) or artificial cerebral spinal fluid (aCSF) was injected respectively into the lateral cerebroventricle of the rat 30 min before the induction of brain ischemia. Neurological deficits were assessed by the five-grade system (Longa's methods). The brain infarct was measured by cresyl violet (CV) staining and infarct volume was analyzed by an image processing and analysis system. The expression of DOR was detected by Western blot. The results showed that 60 nmol TAN-67 significantly reduced the infarct volume (P<0.05), attenuated neurological deficits (P<0.05) and tended to increase the expression of about 60 kDa DOR protein (P>0.05), while 100 nmol naltrindole aggravated ischemic damage and decreased about 60 kDa DOR protein expression (P<0.05). These results suggest that DOR activation protects the brain against acute ischemia/reperfusion injury in rat.