桑枝总生物碱片对肥胖小鼠的保护作用及对肠道菌群的影响

Protective effect of Ramulus Mori(Sangzhi)alkaloids tablets on obese mice and the impact of Ramulus Mori(Sangzhi)alkaloids tablets on gut microbiota

目的探讨桑枝总生物碱片(SZ-A)对肥胖小鼠的保护作用及对肠道菌群的影响。方法选择雄性无特定病原体(SPF)级C57BL/6小鼠,通过12周高糖高脂饮食喂养诱导肥胖小鼠模型,将成模小鼠随机分为模型组(M组)、阳性对照组(PC组)、SZ-A低剂量组(SZ-L组)、SZ-A中剂量组(SZ-M组)、SZ-A高剂量组(SZ-H组),每组10只,另设10只正常小鼠为空白组(N组)。PC组予辛伐他汀混悬液(2.6 mg/kg)灌胃,SZ-L组、SZ-M组、SZ-H组分别以20 mg/kg、40 mg/kg、80 mg/kg的SZ-A剂量灌胃,N组及M组予等体积蒸馏水灌胃,每天灌胃1次,连续12周。比较各组小鼠的Lee′s指数、体质量、生化指标水平、腹股沟白色脂肪组织(iWAT)病理变化、肠道菌群α及β多样性、肠道菌群相对丰度。结果各组Lee′s指数、体质量、血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)及低密度脂蛋白胆固醇(LDL-C)水平比较差异有统计学意义(P<0.05)。N组脂肪细胞排列紧密,同视野下脂肪细胞数量多,体积小。M组脂肪细胞体积明显增大。与M组比较,PC组及SZ-L组脂肪细胞体积稍有减小。SZ-M组及SZ-H组脂肪细胞数量明显增多且细胞体积明显减小,更趋向于N组。SZ-H组Ace指数较M组、PC组及SZ-L组显著升高(P<0.05),Chao指数较PC组及SZ-L组显著升高(P<0.05),Shannon指数较M组、PC组、SZ-L组及SZ-M组显著升高(P<0.05),各组Coverage指数均趋近于1。PCoA分析结果显示,N组、M组、PC组、SZ-L组、SZ-M组、SZ-H组分离度较好,N组与M组水平直线距离较远,且SZ-L组、SZ-M组、SZ-H组菌群结构逐渐趋向于N组。NMDS分析结果显示,Stress值=0.131。在门水平上,与M组比较,SZ-H组厚壁菌门(Firmicutes)及髌骨菌门(Patescibacteria)相对丰度显著降低(P<0.05),拟杆菌门(Bacteroidota)相对丰度显著升高(P<0.05)。在属水平上,与M组比较,SZ-H组鼠杆菌科的未定属(norank_f_Muribaculaceae)相对丰度显著升高(P<0.05),毛螺菌科的未定属(unclassified_f_Lachnospiraceae)、梭菌目的未定属(norank_f_norank_o_Clostridia_UCG-014)及脱硫弧菌属(Desulfovibrio)相对丰度显著降低(P<0.05)。结论SZ-A可部分抵抗高糖高脂饮食诱导的肥胖小鼠体质量增加及脂肪组织扩张,改善脂质代谢,提高菌群物种多样性及部分物种相对丰度。

Objective To explore the protective effect of Ramulus Mori(Sangzhi)alkaloids tablets(SZ-A)on obese mice and the impact of SZ-A on gut microbiota.Methods Male C57BL/6 mice of specific pathogen free(SPF)grade were selected and an obese mouse model was induced in these mice by feeding them with a high-sugar and high-fat diet for 12 weeks.The successfully modeled mice were randomly divided into model group(M group),positive control group(PC group),low-dose SZ-A group(SZ-L group),medium-dose SZ-A group(SZ-M group)and high-dose SZ-A group(SZ-H group),with 10 mice in each group.Additionally,10 normal mice were set as the blank group(N group).The PC group was given simvastatin suspension(2.6 mg/kg)by gavage.The SZ-L group,the SZ-M group and the SZ-H group were orally administered with SZ-A at doses of 20 mg/kg,40 mg/kg and 80 mg/kg,respectively.The N group and the M group were given equal volume of distilled water by gavage.All the groups were given intragastric administration once a day for 12 weeks.Lee′s index,body mass,biochemical indicators,pathological change of inguinal white adipose tissues(iWAT),gut microbiotaαandβdiversity,and relative abundance of gut microbiota were compared among the groups.Results There were statistically significant differences in Lee′s index,body mass,and serum total cholesterol(TC),triglyceride(TG),high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C)levels among the groups(P<0.05).Adipocytes in the N group were closely arranged,with a large number and small volume of adipocytes in the same field of view.The volume of adipocytes in the M group increased significantly.Compared with that in the M group,the volume of adipocytes in the PC group and the SZ-L group decreased slightly.The number of adipocytes in the SZ-M group and the SZ-H group increased obviously and the cell volume decreased obviously,tending towards those in the N group.The Ace index in the SZ-H group was significantly higher than that in the M group,the PC group and the SZ-L group(P<0.05).The Chao index in the SZ-H group was significantly higher than that in the PC group and the SZ-L group(P<0.05).The Shannon index in the SZ-H group was significantly higher than that in the M group,the PC group,the SZ-L group and the SZ-M group(P<0.05).The Coverage index in each group approached 1.The results of PCoA analysis showed that the separation degrees of the N group,the M group,the PC group,the SZ-L group,the SZ-M group and the SZ-H group were relatively good,and the horizontal linear distance between the N group and the M group was relatively far,and the microbial community structure in the SZ-L group,the SZ-M group and the SZ-H group gradually tended towards that in the N group.The results of non-metric multidimensional scaling(NMDS)analysis showed a Stress value of 0.131.At the phylum level,compared with the M group,the SZ-H group exhibited significantly lower relative abundances of Firmicutes and Patescibacteria(P<0.05),and significantly higher relative abundance of Bacteroidota(P<0.05).At the genus level,compared with the M group,the SZ-H group showed significantly higher relative abundance of norank_f_Muribaculaceae(P<0.05),and significantly lower relative abundances of unclassified_f_Lachnospiraceae,norank_f_norank_o_Clostridia_UCG-014 and Desulfovibrio(P<0.05).Conclusion SZ-A can partially resist the increase of body mass and the expansion of adipose tissues induced by a high-sugar and high-fat diet in obese mice,improves their lipid metabolism,enhances microbial species diversity,and increases the relative abundances of partial microbial species.