低蛋白与酮酸饮食干预对糖尿病肾病小鼠肾脏功能的影响

Effects of low-protein and keto acid diet intervention on kidney functions of mice with diabetic nephropathy

目的 探讨低蛋白饮食与补充酮酸饮食对糖尿病肾病小鼠肾脏组织结构和功能的影响。方法 18只雄性db/db小鼠(2型糖尿病肾病模型小鼠)采用随机数字表法分为正常蛋白饮食组、低蛋白饮食组、低蛋白-酮酸饮食组,每组各6只。6只db/m小鼠(db/db小鼠的对照)为正常对照组,给予正常蛋白饮食。相应饮食干预12周,每2周测定小鼠体重。喂养结束后,小鼠当天禁食过夜,第2天记录小鼠的24 h饮水量、排尿量,而后取血测定血糖、肌酐、尿素氮、TG、TC,并处死小鼠取肾称重,测量肾脏横径以大体反映肾脏体积,计算肾重/体重比值,HE染色和PAS染色观察肾脏组织系膜细胞增生情况,免疫组化染色测定肾脏组织转化生长因子-β1、Ⅳ型胶原表达水平。结果 与正常对照组比较,正常蛋白饮食组小鼠体重均增加(均P<0.05),24 h饮水量、排尿量均增加(均P<0.05);血糖、血肌酐、尿素氮、TG、TC水平均升高(均P<0.05);肾脏周围组织脂肪增加,体积增大;染色结果显示肾脏组织内系膜细胞增生增加,转化生长因子-β1、Ⅳ型胶原表达水平均增加(均P<0.05)。与正常蛋白饮食组比较,低蛋白饮食组、低蛋白-酮酸饮食组小鼠体重均降低(均P<0.05),24 h饮水量、排尿量均减少(均P<0.05),血糖、血肌酐、尿素氮、TG、TC水平均下降(均P<0.05);肾脏周围组织脂肪减少,体积有所下降;染色结果显示肾脏组织内系膜细胞增生减轻,转化生长因子-β1、Ⅳ型胶原表达水平均降低(均P<0.05)。结论 低蛋白与酮酸饮食干预可改善糖尿病肾病小鼠肾功能生化指标,降低肾脏组织转化生长因子-β1、Ⅳ型胶原表达,从而改善肾脏功能。

Objective To explore the effects of low-protein diet and keto acid supplementation on renal tissue structure and function in mice with diabetic nephropathy.Methods Eighteen male db/db mice were randomly assigned to the db/db group(normal-protein diet group),db/db+low-protein diet group(low-protein diet group),and db/db+low proteinketo acid diet group(low protein-keto acid diet group),with 6 in each group.Six db/m mice were included in the db/m group(normal control group),which were given normal-protein diet.Dietary intervention lasted for 12 weeks,and the body weight of mice was measured every 2 weeks.After feeding,the mice fasted overnight that day,and on the next day,the 24 h water intake and urine output of mice were recorded,after which,blood glucose,creatinine,urea nitrogen,TG,and TC of the mice were measured;mice were then sacrificed,and their kidneys were collected to calculate the weight,and measure the transverse diameter to roughly calculate the kidney volume,and calculate the ratio of kidney weight to body weight;HE and PAS staining were used to observe the renal tissue mesangial cell proliferation,and imunohistochemical staining were used to evaluate the expressions of transforming growth factor(TGF)-β1 and collagen type IV in kidney tissues.Results Compared with normal control group,the mice of normal-protein diet group showed increased body weight,water intake and urine output(all P<0.05),as well as elevated levels of blood glucose,creatinine,urea nitrogen,TG,and TC(all P<0.05);the tissues around kidneys increased in fat and volume,and the staining results showed increased kidney tissue mesangial cell proliferation,and TGF-β1 and collagen type IV expressions(all P<0.05).Compared with normal-protein diet group,the mice of low-protein diet group and low protein-keto acid diet group displayed decreased body weight,reduced water intake and urine output(all P<0.05),as well as reduced levels of blood glucose,creatinine,urea nitrogen,TG,and TC(all P<0.05);the tissues around kindeys decreased in fat and volume,and the staining results showed less kidney tissue mesangial cell proliferation,and decreased TGF-β1 and collagen type IV expressions(all P<0.05).Conclusion Low-protein diet combined keto acids could improve renal function of diabetic nephropathy mice by improving biochemical indicators and reducing renal tissue TGF-β1 and collagen type IV expressions.