Study On The Expression Changes Of Tight Junction Proteins ZO-1 And Occludin After Hypoxic-ischemic Brain Damage In Neonatral Rats

ObjectiveThe purpose of this study is to explore the mechanism of brain edema of neonatal rats induced by hypoxia-ischemia and to provide new methods for clinical treatment of HIE.Method1. Establishment of HIBD model:Neonatal 7-day-old SD rats were randomly divided into sham-operation control group, HIBD 3 h,6 h,24 h,48 h and 72 h groups (n=8 per group).The model of HIBD was induced by unilateral carotid ligation followed by timed exposure to 8% oxygen. Only separated the left common carotid artery without ligation, sham-operation control group rats were executed at 24 h after the operation. The behavior of the rats was observed during hypoxia.2. General examination of the brain:To observe the appearance of the brain.3. HE staining:To observe the histological change of brain tissue by light microscope.4. Expression of ZO-1 mRNA and occludin mRNA:The expression of ZO-1 mRNA, occludin mRNA in brain tissue of neonatal rats was measured by Real-time Q-PCR method.Results1. Behavior of experimental animals:The behavior of all neonatal rats was normal before operation. Sham-operation control group demonstrated no abnormal behavior; but after experiencing serious hypoxia the rats of HIBD groups showed obvious dystropy.2. General examination of the brain:The ligated cerebralhemisphere of HIBD groups showed obvious pallor and edema at 24 h, and showed liquefactive necrosis lesion at 72 h,or even brain tissue was completely liquefied with dural adhesions. The two cerebralhemispheres of sham group showed no pathological change.3. Histological examination:There was no obvious sign of neuronal damage in control group. After HIBD, neuronal degeneration, necrosis, loss, and glosis appear.4. Expression of ZO-1 mRNA, occludin mRNA in the brain: â‘ The expression of ZO-1 mRNA was high in the sham-operation control group. After HIBD, it began to decrease at 3h,and reached lowest at 24 h, then gradually increased,but it still maintained the lower level at 72 h, compared to the control group, each group was statistically significant(P<0.05), compared to HIBD 24 h group, each group was statistically significant(P<0.05).â‘¡The expression of occludin mRNA was high in the sham-operation control group, but after HIBD, it began to decrease at 3h,and reached lowest at 24 h, then gradually increased,but it still maintained the lower level at 72 h, compared to the control group, each group was statistically significant(P<0.05), compared to HIBD 24 h group, each group was statistically significant(P<0.05). Conclusions1. The HIBD model was successfully established.2. The ligated cerebral hemisphere of HIBD groups showed obvious edema in the neonatal rats.3. After HIBD, neuronal degeneration, necrosis occure.4. The decreased expression of ZO-1 mRNA and occludin mRNA may play an important role in the formation of brain edema after HIBD.