目的 研究双孢菇胞内多糖(IPS)和胞外多糖(EPS)对伴刀豆凝集素A(Con A)所致小鼠免疫性肝损伤的保护作用.方法 小鼠预先ig给予IPS或EPS 100,200和400 mg·kg-1,每日1次,连续12 d,末次给药后4 h尾静脉注射Con A 25 mg·kg-1制备免疫性肝损伤小鼠模型.8 h后眼球取血,取肝、脾和胸腺.全自动生化分析仪测定血清谷丙转氨酶(GPT)和谷草转氨酶(GOT)水平.流式细胞仪检测脾细胞中CD4+和CD8+T淋巴细胞百分比.生化试剂盒检测血清干扰素γ(IFN-γ)和肿瘤坏死因子α(TNF-α)含量及肝组织中超氧化物歧化酶(SOD)活性和丙二醛(MDA)水平.光学显微镜观察肝组织切片的病理改变.结果与正常对照组相比,模型小鼠胸腺指数明显降低(P<0.01),肝、脾指数明显增高(P<0.01);与模型组比较,预先给予IPS 100,200和400 mg·kg-1及EPS 200和400 mg·kg-1小鼠胸腺指数明显升高(P<0.01),肝、脾指数均明显降低(P<0.01).与正常对照组相比,模型小鼠血清GOT和GPT活性及TNF-α和IFN-γ含量显著升高(P<0.01);预先给予IPS及EPS 200和400 mg·kg-1小鼠血清GOT和GPT活性及TNF-α和IFN-γ含量较模型组显著降低(P<0.01).与正常对照组相比,模型小鼠肝组织SOD活性降低(P<0.01),MDA水平升高(P<0.01);与模型组比较,预先给予IPS及EPS 200和400 mg·kg-1 SOD活性明显升高(P<0.01),MDA水平降低(P<0.01).与正常对照组相比,模型小鼠脾细胞中CD4+T淋巴细胞百分比和CD4+/CD8+T淋巴细胞比值明显下降(P<0.01);预先给予IPS和EPS 400 mg·kg-1 CD4+T淋巴细胞百分比与模型组比较明显升高(P<0.01),CD4+/CD8+T淋巴细胞比值变化不明显.镜下观察模型组小鼠肝组织出现明显的病理改变,预先给予IPS和EPS能减轻Con A引起的病理变化.结论 双孢菇IPS和EPS对小鼠免疫性肝损伤有一定的保护作用,其机制可能与清除自由基、抑制脂质过氧化和调节免疫系统平衡有关.%OBJECTIVE To evaluate the protective effect of Agaricus bisporus intracellular polysaccharides(IPS) and exopolysaccharides (EPS) on immunological liver injury induced by concanavalin A (Con A). METHODS Mice were pretreated with IPS and EPS (100, 200 and 400 mg kg- 1, ig) daily for 12 d. Immunological liver injury was induced by Con A 25 mg·kg-1 by injection via the tail vein of mice.Eight hours after injection of Con A, the indexes of the liver, spleen and thymus, serum level of glutamicpyruvic transaminase (GPT), glutamic-oxalacetic transaminase (GOT), tumor necrosis factor-α (TNF-α) and interferon- γ (IFN- γ), splenic lymphocyte percentages of CD4 + and CD8 + , and liver homogenate content of superoxide dismutase (SOD) and malondialdehyde (MDA) were measured. Liver pathological changes were observed by HE staining. RESULTS Compared with normal group, the autoimmune liver injury in mice induced by Con A resulted in an increase in the liver index (P<0.01) , spleen index (P<0.01), the activity of GPT (P<0.01) and GOT (P<0.01), the content of TNF- α (P<0.01) and IFN- γ (P< 0.01), and the level of MDA (P<0.01), but a decrease in the thymus index (P<0.01), the percentage of CD4+ (P<0.01) , the ratio of CD4+/CD8+ (P<0.01), and SOD activity (P<0.01). Compared with model group, treatment with IPS (200 and 400 mg·kg-1) and EPS (200 and 400 mg·kg-1 ) respectively resulted in an increase in the thymus index (P<0.01) but in a decrease in the liver index and spleen index (P<0.01). Similarly, the activity of GOT and GPT was decreased obviously (P<0.01), and the content of TNF-α and IFN-γ in IPS and EPS 200 and 400 mg·kg-1 groups was decreased. Compared with model group, the activity of SOD in IPS and EPS (200 and 400 mg·kg- 1) group was increased (P<0.01) while MDA was decreased (P<0.01). Moreover, the percentage of CD4 + Iymphocytes decreased (P<0.01), whereas no significant difference was found in the ratio of CD4 +/CD8 + .Pathological changes of the liver were observed under a microscope. Pretreatment with IPS and EPS could effectively reduce the liver injury induced by Con A. CONCLUSION IPS and EPS have certain protective effect on immunological liver injury, which may be related to their ability to clean up free radicals, control lipid peroxidation and regulate the balance of the immune system.
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