益生菌灌服/健康大鼠肠道微生物群移植对大鼠妊娠期糖尿病的治疗作用及其机制

Therapeutic effect and mechanism of probiotic administration/intestinal microbiota transplantation of healthy rats on gestational diabetes mellitus in rats

目的观察益生菌灌服/健康大鼠肠道微生物群移植对大鼠妊娠期糖尿病(GDM)的治疗作用,探讨其作用机制。方法取70只SD雌性大鼠和35只SD雄性大鼠,2:1合笼交配交配成功后随机抽取10只雌鼠为对照组(记为第0天),其余60只雌鼠腹腔注射链脲佐菌素建立GDM大鼠模型,造模成功(大鼠随机血糖≥16.7 mmol/L)后将40只大鼠分为一、二、三、四组,每组各10只。第5天一组大鼠予359.708 mg/kg益生菌补充剂灌胃,二组大鼠予1 mL/100g的健康大鼠粪菌混悬液灌胃,三组大鼠给予359.708 mg/kg益生菌补充剂、1mL/100 g健康大鼠粪菌混悬液灌胃,四组与对照组大鼠予10 mL/kg的PBS缓冲液灌胃,各组大鼠每日灌胃1次,连续14天。第19天取各组大鼠,采用口服葡萄糖耐量试验测算血糖;第20天取各组大鼠,麻醉后留取结肠内容物及结肠组织,采用GC-2010气相色谱仪测算大鼠结肠内容物短链脂肪酸(乙酸、丙酸、丁酸及异丁酸)含量,分别采用RT-qPCR法Western Blotting法检测各组结肠组特异性G蛋白偶联游离脂肪酸受体(GPR43)、胰高血糖素样肽-1(GLP-1)的mRNA及蛋白。结果与对照组相比,第20天四组大鼠糖耐量低,结肠内容物乙酸、丁酸、异丁酸含量低,结肠组织GPR43 mRNA、GLP-1mRNA及蛋白相对表达量均低(P均<0.05)。与四组相比,一、二、三组大鼠糖耐量高,第20天时结肠组织GPR43 mRNA、GLP-1mRNA及蛋白相对表达量均高(P均<0.05)。结论益生菌灌服/健康大鼠肠道微生物群移植可改善大鼠GDM,益生菌灌服/健康大鼠肠道微生物群移植可能通过增加结肠内容物中SCFAs含量,提高结肠组织GPR43、GLP-1mRNA及蛋白表达,改善大鼠的GDM。

Objective To observe the therapeutic effects of probiotics gavage/healthy rat intestinal microbiota trans⁃plantation on gestational diabetes mellitus(GDM)in rats and to investigate their mechanisms.Methods Seventy female and 35 male Sprague-Dawley(SD)rats were used,with a 2:1 ratio for mating.After successful mating,10 female rats were randomly selected as the control group(marked as day 0).The remaining 60 female rats were injected intraperitoneal⁃ly with streptozotocin to establish the GDM models.Upon successful modeling(random blood glucose≥16.7 mmol/L),40 rats were divided into four groups,with 10 rats in each.On the 5th day,rats in the first group received a gavage of 359.708 mg/kg probiotics supplement,rats in the second group received a gavage of 1 mL/100g of healthy rat fecal micro⁃biota suspension,rats in the third group received both 359.708 mg/kg probiotics supplement and 1 mL/100g healthy rat fecal microbiota suspension,and rats in the fourth group,along with the control group,received 10 mL/kg PBS buffer ga⁃vage.Each group was gavaged once daily for 14 consecutive days.On the 19th day,an oral glucose tolerance test was per⁃formed to measure blood glucose levels.On the 20th day,colonic contents and tissues were collected after anesthesia to measure the short-chain fatty acids(SCFAs)(acetate,propionate,butyrate,and isobutyrate)content using the GC-2010 gas chromatograph.The specific G protein-coupled free fatty acid receptor(GPR43)and glucagon-like peptide-1(GLP-1)mRNA and protein levels were detected using RT-qPCR and Western blotting.Results Compared with the control group,the GDM rats on the 20th day exhibited lower glucose tolerance,reduced levels of acetate,butyrate,and isobutyr⁃ate in colonic contents,and lower relative expression levels of GPR43 mRNA,GLP-1 mRNA,and protein in colonic tis⁃sues of the fourth group(all P<0.05).Compared with the fourth group,the first,second,and third groups showed higher glucose tolerance and increased relative expression levels of GPR43 mRNA,GLP-1 mRNA,and protein in the colonic tis⁃sues on the 20th day(all P<0.05).Conclusions Probiotics gavage and healthy rat intestinal microbiota transplantation can improve GDM in rats.This improvement may be achieved by increasing SCFA content in colonic contents and enhanc⁃ing the expression of GPR43,GLP-1 mRNA,and protein in colonic tissues,thus ameliorating GDM in rats.