冬虫夏草提取物减轻大鼠移植肾慢性排斥反应的作用及其机制探讨

Effect of cordycepssinensis extract on chronic renal allograft rejection in rats and its action mechanism

目的探讨冬虫夏草提取物对大鼠移植肾慢性排斥反应的影响及其机制。方法以Brown-Norway大鼠为供者，Lewis大鼠为受者，制备大鼠肾移植慢性排斥反应模型。移植对照组的受者移植后以生理盐水灌胃至术后8周；冬虫夏草低剂量组的受者移植后以冬虫夏草提取物5mg·kg^-1·d^-1灌胃8周；冬虫夏草高剂量组的受者移植后以冬虫夏草提取物10mg·kg^-1·d^-1灌胃8周。另设同系移植对照组，该组受者移植后以生理盐水灌胃至术后8周。8周后取移植肾脏，观察组织病理变化，标准化移植肾损伤评分评价移植肾功能。流式细胞仪检测外周血的CD4^＋CD25^＋T淋巴细胞及辅助性T淋巴细胞17型（TH17细胞）的分布状态，同时检测血清中白细胞介素（IL）17、L-23和IL-2的浓度。结果移植后8周，移植对照组、冬虫夏草低剂量组和冬虫夏草高剂量组移植肾组织均出现不同程度的慢性排斥反应病理改变，但给予冬虫夏草提取物处理者的病理改变明显较移植对照组轻，其标准化移植肾损伤评分也明显低于移植对照组（P〈0．05）。与移植对照组相比，冬虫夏草提取物处理的两组CD4^＋CD25^＋T淋巴细胞占CD4^＋T淋巴细胞的比例增高，CD4^＋IL-17^＋T淋巴细胞占CD4^＋T淋巴细胞的比例降低，差异有统计学意义（P〈0．05）。冬虫夏草提取物处理的两组血清IL-2水平高于移植对照组，而IL-17和IL-23的水平低于移植对照组，差异均有统计学意义（P〈0．05）。结论冬虫夏草提取物能够减轻大鼠移植肾的慢性排斥反应，其作用机制可能是通过改变CD4^＋IL-17^＋T淋巴细胞与CD4^＋CD25^＋T淋巴细胞的平衡，上调抗炎症细胞因子，减少炎症细胞因子来实现的。

Objective To investigate the influence of Cordycepssinensis extract on chronic renal allograft rejection in rats and its action mechanism. Methods Brown-Norway rats and Lewis rats were used to establish the kidney transplantation model of chronic rejection. In the allograft control group, saline was given by lavage per day for 8 weeks; In the low dose group, Cordycepssinensis extract was given by lavage at a dosage of 5 mg/kg per day for 8 weeks; In the high dose group, Cordycepssinensis extract was given by lavage at a dosage of 10 mg/kg per day for 8 weeks. In addition, the isograft control group was set up, saline was given by lavage per day for 8 weeks. The kidney was harvested for histology after 8 weeks, and the graft histology was quantified by using the Banff sum score. The distribution of Th17 cells and Treg cells was detected by flow cytometry, and the concentrations of interleukin （IL）-17, IL-23 and IL-2 in the medium were determined at the same time. Results All allografts of each group developed chronic renal allograft rejection 8 weeks after transplantation. The treatment with Cordycepssinensis extract significantly alleviated the chronic renal allograft rejection and the Banff sum score was significantly lower as compared with the allograft control group （P〈0. 05）. As compared with the allograft control group, the ratio of Treg cell in Cordycepssinensis extract treatment groups was remarkably increased （P〈0. 05）, and the ratio of Th17 cells in Cordycepssinensis extract treatment groups was remarkably reduced （P〈0.05）. Cordycepssinensis extract also remarkably enhanced the production of IL-2 as compared with the allograft control group （P〈0.05）, while IL-17 and IL-23 levels were significantly lower than those in the allograft control group （P 〈 0. 05 ）. Conclusion Cordycepssinensis extract can significantly alleviate the chronic rejection of the renal allograft. Changing the balance of Th17/Treg axis, increasing the anti-inflammatory cytokines and reducing the inflammation cytokines may be involved in the mechanisms.