滋肾阴复方多糖对糖皮质激素诱导大鼠胸腺萎缩的保护作用及机制

目的观察滋肾阴中药复方总多糖对糖皮质激素导致的胸腺细胞凋亡及胸腺萎缩的保护作用。方法实验大鼠分为5组，对照组、模型组、模型＋总多糖低、中、高剂量组。模型组给予氢化可的松腹腔注射50mg／kg，连续7d。实验结束称体重、胸腺重量；分离胸腺细胞，进行流行细胞仪检测细胞凋亡；采用Westernblot检测各组大鼠胸腺的糖皮质激素受体α（GRα）、凋亡相关蛋白caspase8、caspase3的表达。结果糖皮质激素造模导致大鼠体重降低、肾上腺、胸腺重量降低；胸腺细胞凋亡率显著升高；胸腺组织GR、caspase8、caspase3表达显著升高。多糖应用之后，胸腺重量较模型组升高，胸腺细胞凋亡率较模型组下降，caspase8、caspase3的表达显著降低，但GR的蛋白表达未见有影响。结论提取自具滋肾阴功效复方的总多糖具有拮抗糖皮质激素诱导的胸腺萎缩、胸腺淋巴细胞凋亡的作用，其机制涉及下调caspase8、caspase3表达，但和GR的蛋白表达水平无关。

The effects and mechanisms of polysaccharides derived from Shenyin-tonifying formula on the atrophy of thymus induced by glucocorticoids

Objective To observe the protective effects of total polysaccharides extracted from a formula with Shenyin- tonifying afficacy on atrophy and apoptosis of thymus cells induced by glucocorticoids. Methods Rats were assigned into five groups： control, model, model＋ low, middle or high doses ofpolysaccharides. The model group was given an con- secutive peripherial injection of cortisol at a dose of 50 mg/kg for 7 days. The apoptotic rate of thymus cells was measured with flowcytometry. The protein expression of GRα, caspase 8, caspase 3 was measured with Western blotting. Results Rats in model group showed decreases in the body, adrenal and thymus weight. The apoptotic rate of thymus cells was sig- nificantly increased. The protein expression of GR, caspase 8, caspase 3 were all up-regulated. After treatment with pol- ysaccharides, the thymus weight was partially but significantly increased, compared the model group, The apoptotic rate of thymus cells was decreased accompanying decreases in the protein expression of caspase 8, caspase 3. But the GR ex- pression showed no change. Conclusions The total polysaccharides from Shenyin-tonifying formula can inhibit the thymus atrophy and cell apoptosis induced by glucocorticoids. The caspase 8, caspase 3, but not GR involve in the effects of polysaccharides.