Schisandra Chinensis extract prevents radiation-induced lymphocyte reduction in mice and the related mechanisms

Objective To study the efficacy of Schisandra Chinensis(SC) extract in prevention of lymphocyte reduction caused by radiation and to explore the related mechanism.Methods: A total of 48 BALB/c mice were divided into 4 groups: SC treated group(SC+ray),NS control group(NS+ray),SC control group(SC),and normal control group(NS).After BALB/c mice were radiated with 6 Gy,the WBC and lymphocyte numbers were counted;T lymphocyte subsets in peripheral blood were detected by immunofluorescence cell staining;morphology of thymocytes was observed by Gimsa staining;lymphocyte subsets and apoptosis rate of thymocytes were examined by flow cytometry;Bcl-2 and Fas mRNA expressions in thymus tissues were measured by RT-PCR.Results: In NS+ray group,the quantities of WBC,lymphocytes,and lymphocyte subsets were significantly decreased after radiation(P0.01),but in SC+ray group,the numbers of WBC and lymphocytes were significantly increased compared with those in NS+ray group(P0.01).The percentages of CD3+,CD4+,and CD8+ T cells in peripheral blood were significantly increased in SC+ray group compared with those in NS+ray group(P0.01).The quantity of thymocytes was decreased and apoptosis of thymocytes was increased in NS+ray group;cell apoptosis rate in SC+ray group was significantly increased than that in NS+ray group([2.87±1.03]% vs [21.32±2.56]%,P0.01).The expression of Bcl-2 mRNA was significantly downregulated and Fas mRNA was upregulated in NS+ray group(P0.01);Bcl-2 mRNA was upregulated and Fas mRNA was significantly downregulated in SC+ray group compared with those in NS+ray group(P0.01).Conclusion: SC can prevent radiation-induced lymphocyte reduction through regulating apoptosis of thymocytes,which is mediated by upregulation of Bcl-2 and downregulation of Fas.