二甲双胍对糖尿病大鼠血清同型半胱氨酸水平及肠道菌群的影响

Effects of metformin on serum homocysteine level and intestinal flora in diabetes rats

目的 探讨二甲双胍对糖尿病大鼠血清同型半胱氨酸(Hcy)水平及肠道菌群的影响。方法 健康雄性SD大鼠经高糖高脂饲料喂养4周,随机分为正常对照组、二甲双胍组、模型组。二甲双胍组、模型组一次性腹腔注射1%链脲佐菌素溶液35 mg/kg,建立糖尿病模型。二甲双胍组每日给予200 mg/kg二甲双胍溶液灌胃,正常对照组、模型组每日给予等量的双蒸水灌胃,均连续灌胃8周。观察大鼠的进食、饮水、大小便、毛色、活动情况;于干预第1、4、8周末称重,取尾尖血检测血糖;用ELISA法检测血清Hcy,用全自动生化分析仪检测血清TG、TC、HDL-C、LDL-C;用HE染色法观察结肠组织病理变化;采集结肠根部粪便,用16S高通量测序检测肠道菌群,对测序结果进行菌群操作分类单元(OTU)分析及Alpha多样性分析。结果 正常对照组状态良好,模型组有典型糖尿病症状,二甲双胍组糖尿病症状缓解。与正常对照组比较,模型组干预第1、4、8周血糖高(P均<0.05);与模型组比较,二甲双胍组干预第4、8周血糖低(P均<0.05)。与正常对照组比较,模型组血清Hcy、LDL-C水平高(P均<0.05);与模型组比较,二甲双胍组血清Hcy、LDL-C水平低(P均<0.05)。正常对照组结肠组织未见明显病理变化;模型组结肠固有层可见较多炎细胞浸润,肠道结构损伤程度较重,细胞形态不完整;二甲双胍组炎细胞浸润较轻,细胞形状与正常对照组差别小。与正常对照组比较,模型组OTU值低(P<0.05);与模型组比较,二甲双胍组OTU值高(P<0.05);二甲双胍组肠道菌群物种构成及相对丰度与正常对照组相近,与模型组有差异。结论 二甲双胍能降低糖尿病大鼠血清Hcy水平,调节肠道菌群。

Objective To explore the effects of metformin on serum homocysteine level and intestinal flora in diabetes rats. Methods After 4-week high sugar and high-fat feeding, healthy male SD rats were randomly divided into the normal control group, metformin group, and model group. Rats in the metformin group and model group were intraperitoneally injected with 35 mg/kg of 1% streptozotocin solution to establish diabetes models. Rats in the metformin group were given 200mg/kg metformin solution by gavage every day. And rats in the normal control group and model group were given the same amount of double-distilled water for 8 weeks. We observed not only the rats’ eating, drinking, defecation, hair color and activity, but weigh at the end of the 1st, 4th and 8th weeks of intervention, and measured blood glucose from the tail tip. We tested serum Hcy by ELISA, and serum TG, TC, HDL-C and LDL-C by automatic biochemical analyzer. The pathological changes of colon tissues were observed by HE staining, and fecal samples collected from the root of the colon of rats were used to detect the intestinal flora by 16S high-flux sequencing. Then we analyzed the sequencing results for the flora Operational Taxonomic Unit(OTU) analysis and Alpha diversity analysis. Results The normal control group was in good condition, the model group had typical symptoms of diabetes, and the metformin group had symptoms of diabetes relieved. Compared with the normal control group, the blood glucose in the model group was higher at the 1st, 4th and 8th weeks of intervention(P<0. 05). Compared with the model group, the blood glucose in the metformin group was lower at the 4th and 8th weeks of intervention(P<0. 05). Compared with the normal control group, the serum Hcy and LDL-C levels in the model group were higher(both P<0. 05). Compared with the model group, the levels of serum Hcy and LDL-C in the metformin group were lower(both P<0. 05). No obvious pathological changes were found in the colon tissues of the normal control group. In the model group, there were many inflammatory cells infiltrating in the lamina propria of the colon, the intestinal structure was seriously damaged, and the cell morphology was incomplete. The infiltration of inflammatory cells in the metformin group was lighter, and the cell shape was slightly different from that in the normal control group. Compared with the normal control group, the OTU value of the model group was lower(P<0. 05), and the OTU value of the metformin group was higher than that of the model group(P<0. 05). The species composition and relative abundance of intestinal flora in the metformin group were similar to those in the normal control group, but different from those in the model group. Conclusion Metformin treatment can reduce blood sugar and serum homocysteine level and regulate intestinal flora in diabetes rats.