1,25(OH)_(2)D_(3)对2型糖尿病大鼠肾功能损伤的保护作用及SIRT4表达水平影响研究

Study on protective effect of 1,25(OH)_(2)D_(3) on renal function damage in type 2 diabetic rats and influence of SIRT4 expression level

目的观察1,25羟基维生素D_(3)[1,25(OH)_(2)D_(3)]在2型糖尿病大鼠中对肾脏的保护作用及沉默信息调节蛋白4(sirtuin 4,SIRT4)在肾脏组织中的表达情况,探讨1,25(OH)_(2)D_(3)改善糖尿病肾病的相关机制。方法将24只SD大鼠随机分为对照组(n=6)、糖尿病组(n=18),对照组每日普通大鼠饲料喂饲,糖尿病组使用高脂高糖饲料喂饲,8周后,糖尿病组大鼠腹腔注射链脲佐菌素40 mg/kg,继续给予高脂高糖饲料喂养1周,采血检测血糖,随机将12只成功建立糖尿病的大鼠分为糖尿病组(n=6)和糖尿病+骨化三醇组(n=6),之后对照组和糖尿病组大鼠每日使用花生油灌胃,糖尿病+骨化三醇组大鼠每日使用骨化三醇灌胃,持续4周,麻醉后取血检测相关生化指标,取下两肾脏,制作病理切片并检测SIRT4表达水平。结果实验后各组大鼠尿酸、肌酐、尿素氮和血糖水平比较差异均有统计学意义(均P<0.01),其中尿酸[(180.20±11.56)、(161.69±7.80)、(142.25±14.51)mmol/L]、肌酐[(36.60±1.11)、(32.46±2.66)、(29.48±2.90)μmol/L]和血糖[(21.32±2.74)、(18.20±1.42)、(4.92±1.03)mmol/L]水平均为糖尿病组>糖尿病+骨化三醇组>对照组(均P<0.01),尿素氮[(7.86±0.39)、(8.16±0.47)、(6.02±0.98)μmol/L]水平为糖尿病组=糖尿病+骨化三醇组>对照组(P<0.01);对照组大鼠肾脏未观察到明显病理改变,糖尿病组大鼠肾脏-肾远曲小管扩张、上皮肿胀,糖尿病+骨化三醇组大鼠肾间质血管扩张,远曲管扩张;各组大鼠SIRT4表达水平比较,差异均有统计学意义(均P<0.05),其中对照组>糖尿病+骨化三醇组>糖尿病组(0.71±0.07、0.42±0.06、0.52±0.08)(均P<0.05)。结论1,25(OH)_(2)D_(3)对糖尿病大鼠的肾脏具有一定的保护作用,SIRT4表达水平的上调可能是其中机制之一。

Objective To observe the protective effect of 1,25 hydroxy vitamin D_(3)[1,25(OH)_(2)D_(3)]on the kidneys of type 2 diabetic rats and the expression of sirtuin 4(SIRT4)in kidney tissues,explore related mechanisms of 1,25(OH)_(2)D_(3)improving diabetic nephropathy.Methods 24 SD rats were randomly divided into a control group(n=6)and a diabetes group(n=18).The control group was fed daily with ordinary rat feed,and the diabetes group was fed with high-fat and high-sugar feed.After eight weeks,rats in the diabetic group were intraperitoneally injected with streptozotocin 40 mg/kg,and continued to be fed with high-fat and high-sugar feed for one week.Blood was collected for blood glucose testing.12 rats with successfully established diabetes were randomly divided into diabetic group(n=6)and diabetes+calcitriol group(n=6).After that,rats in the control group and diabetic group were given peanut oil by gavage daily,and rats in the diabetes+calcitriol group were given calcitriol by gavage daily for four weeks.The blood was taken after anesthesia to detect the relevant biochemical indicators,the two kidneys were removed to make pathological sections and detect the expression level of SIRT4.Results After the experiment,there were statistically significant differences in the levels of uric acid,creatinine,urea nitrogen and blood glucose among different groups(all P<0.01).For the levels of uric acid[(180.20±11.56),(161.69±7.80),(142.25±14.51)mmol/L],creatinine[(36.60±1.11),(32.46±2.66),(29.48±2.90)μmol/L]and blood glucose[(21.32±2.74),(18.20±1.42),(4.92±1.03)mmol/L],all were diabetes group>diabetes+calcitriol group>control group(all P<0.01),while the urea nitrogen level[(7.86±0.39),(8.16±0.47),(6.02±0.98)μmol/L]were diabetes group=diabetes+calcitriol group>control group(P<0.01).In the control group,no obvious pathological changes were observed in the kidneys.In the diabetic group,kidney-distal convoluted tubules were dilated and the epithelium was swollen.In the diabetes+calcitriol group,the kidneys interstitial dilated and the distal curved tubes were dilated.There were statistically significant differences in the expression level of SIRT4 among different groups(all P<0.05),which was control group>diabetes+calcitriol group>diabetes group(0.71±0.07,0.42±0.06,0.52±0.08)(all P<0.05).Conclusion 1,25(OH)_(2)D_(3)has a certain protective effect on the kidneys of diabetic rats,and the up-regulation of SIRT4 expression may be one of the mechanisms.