罗汉果皂甙提取物对1型糖尿病小鼠细胞免疫功能的影响

目的:探讨罗汉果皂甙提取物(mogrosideextract,MG)对1型糖尿病(type1diabetesmellitus,TIDM)小鼠脾脏淋巴细胞亚群及细胞因子表达的影响。方法:给予Balb/c小鼠腹腔注射200mg/kgbw四氧嘧啶造模(TIDM)。成模后按血糖随机分为,糖尿病对照组,低、高剂量MG治疗组(150、300mg/kgbw);正常小鼠也按血糖随机分为正常对照组以及低、高剂量MG组。连续灌胃30d,实验结束时测小鼠血糖水平,流式细胞仪检测脾脏淋巴细胞CD4、CD8亚群以及细胞因子IFN-γ,TNF-α和IL-4的表达,并观察胰腺组织学变化。结果:与正常对照组相比,TIDM小鼠血糖显著升高,脾脏CD8+淋巴细胞数目显著增加,CD4/CD8比值降低;IFN-γ、TNF-α的表达水平升高。MG尤其是低剂量组能降低血糖,改善胰腺的病变程度以及下调IFN-γ、TNF-α的表达水平,增加TIDM小鼠脾脏CD4+淋巴细胞数目,使CD4/CD8比值恢复正常,此外,还可显著增加正常小鼠和TIDM小鼠脾脏淋巴细胞IL-4的表达水平,但对正常小鼠其它各项指标无明显影响。结论:MG能通过免疫调节机制对TIDM小鼠脾脏淋巴细胞的抗原表达进行调控,拮抗TIDM时出现的细胞免疫功能失衡,进而对TIDM起到一定的治疗作用。

EFFECTS OF MOGROSIDE EXTRACT ON CELLULAR IMMUNE FUNCTIONS IN ALLOXAN-INDUCED DIABETIC RATS

Objective:To study the effect of mogroside extract on splenic lymphocytes subsets and the cytokines expression levels of type 1 diabetes mellitus (TIDM) mice. Method:Balb/c mice were rendered diabetic by a single intra-peritoneal injection of alloxan, at dose of 200 mg/kg bw. After confirmation of TIDM, control and diabetic mice were further subdivided into the following six groups: control (C), control low dose MG (150 mg/kg bw, C-LMG), control high dose MG (300 mg/kg bw, C-HMG), diabetic (D), diabetic low dose MG (150 mg/kg bw, D-LMG), diabetic high dose MG (300 mg/kg bw, D-HMG). The MG or saline was administered by gavage daily over 30 d. At the end of the experiment, determinations of serum glucose concentration, splenic lymphocyte subpopulation and cytokines production (IFN- , TNF- and IL-4) and histopathological examinations of pancreatic islets were carried out. Results:TIDM mice presented hyperglycemic manifestation and significant injury in islets. Besides, alloxan induced a markedincrease in the CD8 expression (thus a dramatic decrease in CD4/CD8) and production of IFN- and TNF- in splenocytes. The MG, especially at the low dose effectively attenuated the early clinical symptoms, biochemical abnormalities, pathological damages in pancreatic islets and regulated the immune dysfunction in alloxan-induced TIDM mice, possibly by influencing (up-regulating) the CD4 T lymphocyte subsets and CD4/CD8 ratio, and remodeling the intracellular cytokine profiles (reducing the expression of pro-inflammatory Th1 cytokines: IFN- , TNF- towards a beneficial Th2 pattern). MG therapy had no obvious effect on normal mice, except that at the low dose MG could up-regulat the IL-4 expression . Conclusion:MG could exhibit anti-diabetic effects, due to its immunity-regulating capacity on TIDM, and may be used as a new natural drug for prevention and treatment of TIDM.