Molecular Mechanism Study On Apoptosis Of Hematopoietic Cells, Immunity Cells, Germ Cells Induced In Irradiated Mice

Objective 1.To study on hematopoietic cells, thymocytes, splenetic, testicular and liver cells apoptosis and the expression of P53 gene in irradiated mice .2.To study the therapeutic effects of Angelica polysaccharide(APS) on immunity and germ function and its mechanism in radiation-injured mice.Methods 1.The mice were irraddiated with x-rays..Apoptosis was detected by HE, light microscope and flow cytometry(FCM).P53 gene expression was detected by immunohistochemistry S-P method. 2.The influence of APS on immunity cells and germ cells were observed by peripheral blood leucocyte,index of spleen,thymus and testicle in exposed to 5Gy radiation. The effect on percentage of apoptosis rate and P53 gene expression of thymocyte, splenocyte, testicular cells in mice were detected by FCM and immunohistochemistry S-P method.Results 1. In the range of 2-8GY,apoptosis of hematopoietic cells, thymocytes, splenetic, testicular and liver cells were increased with the dosage increasing in irradiated mice and there was a significant difference in different time group(P<0.01).Apoptosis of hematopoietic cells, thymocytes, splenetic, testicular within 12hrs were increased with time extended. FCM analysis showed that cells delayed in Gl phase and there was a sub-Gl peak.The apoptot peak were highest at 8 or 12hrs,but at 24hrs in liver, the cells were delayed in S and G2/M phase. 2.The expression of P53 was obviously increased when apoptosis of cells occurred.There was a significent difference between experimental and normal controlgroup(P<0.05).P53 gene was not detected in liver. 3. The peripheral blood leucocyte was a significently higher in the group treated with APS 3 days after 5Gy X-ray exposure than in the group treated only by X-ray irradiation(P<0.05). As for APS on the 7th day,the index of spleen,thymus and testicle were significently higher in the group treated with APS than in the group treated only by X-ray irradiation(P<0.05). There was no significant change was found in apoptosis rate between in the group treated with APS and in the group treated only by X-ray irradiation at 12hrs after irradiation.(P > 0.05). Apoptosis rate was no significant change between in the group treated with APS and normal control group at 7th day (P > 0.05). The expression of P53 protein in the APS group was lower than irradiated group and there was a significant difference between them (P<0.05).Conclusion 1.Radiation may induced apoptosis of hematopoietic cells ^ thymocytes^ splenetic x testicular cells delayed in Gl phase. Its mechanism is associated with upregulation of P53 gene. 2. .Radiation may induced apoptosis of liver cells and its mechanism has no relation with the P53 gene expression,cells were delayed in S and G2/M phase .3. Apoptosis of hematopoietic cells, thymocytes, splenetic, testicular and liver cells were increased with the dosage increasing in irradiated mice and within 12hrs apoptosis were increased with time extended. 4.APS has therapeutic effects on irradiated immunity system and germ system in mice, and its mechanism properbly is associated with down-regulation of P53 protein in spleen, thymus and testicle.