EVALUATION OF APOPTOSIS IN HIPPOCAMPAL CELLS OF RAT FOLLOWING INTRAVENOUS INJECTION OF BONE MARROW STROMAL CELLS IN ISCHEMIA-REPERFUSION MODEL

Cerebral ischemia is known as a major worldwide problem and subsequent reperfusion leads to apoptosis or programmed cell death. Specific regions of the brain and specific types of neurons, including hippocampal CA1 pyramidal neurons are more sensitive in cerebral ischemia. Today cell therapy is one of the common treatments that spread among the researchers. In this study, we evaluated apoptosis in hippocampal cells of rat following intravenous injection of bone marrow stromal cells (BMSCs) in ischemia-reperfusion model. In this study, adult male wistar rats (n=40) weighting (250-300g) were used. The rats were divided into the five groups of 8 animals including: control, sham, ischemia, vehicle, and treatment. In the sham group surgery was performed without blocking common carotid arteries. In ischemia group common carotid arteries blocked for twenty minutes and then allowed to reperfusion. In the vehicle group 7 days after ischemia, 30µl PBS was injected via tail vein. In the treatment group BMSC cells (800000/ 30 µl suspension) were injected into the tail vein 7 days after ischemia. And 72 hours before transplantation, the cells were labeled with Brdu. 12 days after ischemia, rats were fixed with 4% Paraformaldehyde through transcardial perfusion and their brains were removed. After histological processing, 5 micron sections were prepared for staining. For immunohistochemistry study anti-Brdu anti-body was used and BMSC cells were identified. Apoptotic cells were detected by TUNEL staining. Sever apoptosis was observed in ischemia group. The mortality rate in the group which was treated with BMSC was lower. Ischemia-reperfusion for 20 minutes causes damage and extensive neural death in the hippocampus, especially in CA1 region and injection of bone marrow stromal stem cells significantly decreased the number of apoptotic neurons.