60Coγ照射加深低温保存对大鼠同种带瓣主肺动脉免疫原性的作用

目的本实验应用60Coγ射线照射加液氮深低温保存大鼠同种带瓣主肺动脉（Valvedpulmonary hongraf conduit，VPHC），并建立大鼠VPHC颈总动脉移植模型，观察不同照射剂量对同种带瓣主肺动脉免疫原性的作用，寻找合适照射剂量，为进一步基础研究及临床应用提供理论依据。方法1月龄雌性Wistar大鼠50只，作为供体，成年雄性赋）大鼠50只，作为受体，随机分为实验对照组（单纯深低温保存组）、300Gy照射组、600Gy照射组、900Gy照射组和1200Gy照射组，另取10只sD大鼠行颈总动脉切断吻合术，作为空白对照组。应用流式细胞术对VPHC移植术后1周、2周、3周受体鼠外周血行CD4＋T细胞及CD8＋T细胞检测。结果600Gy照射组VPHC移植术后1周、2周、3周CD4＋T细胞、cD8＋T细胞百分率及cD4＋／cD8＋与空白对照组相比无显著性差异（P〉0．05），与实验对照组相比差异显著（P〈0．01）。结论应用60Gy 60Coγ射线对VPHC进行照射在保持VPHC活性的同时明显降低了其免疫原性。

Immunogenicity in Rat Conduit Pulmonary Valved Homograft with ~(60)Co Gamma Irradiation and Cryopreservation

Objective To determine the suitable dosage of 60Coγ ray to be used prior to cryopreservation in order to reduce the immunogenicity of CPVH. Methods fifty one-month old female Wistar rats were used as donors and were divided into five groups （ n = 10）. Fifty SD adult rats were used as recipients and were divided into five groups respectively （ n = 10）. Four＇experimental groups were irradiated with 60Coγ ray of different dosages prior to cryopreservation; 300 Gy group, 600 Gy group, 900 Gy group, 1 200 Gy group. The experimental control group received cryopreservation only. And ten SD rats underwent right carotid artery end-to-end anastomosis were used as a control group. Flow Cytometry was used to test CD4 ＋ , CD8 ＋ T-cells in peripheral blood of recipient rats at weekly interval of 1,2,3 weeks postoperatively. Results There was no significant difference between 600 Gy group and the control group in percentages of CD4 ＋ , CD8 ＋ T-cells. Conclusion The dosage of 600 Gy 60Coγray irradiation prior to cryopreservation would be the optimal dosage for reducing inwmmogenicity of the VPHC in rats.