骨化三醇对糖尿病大鼠肾脏白细胞介素17表达的影响

Effect of calcitriol on the expression of interleukin-17 in kidneys of diabetic rats

目的 探讨骨化三醇对糖尿病大鼠肾脏白细胞介素17（IL-17）表达的影响.方法 8周龄健康雄性SD大鼠45只,链脲佐菌素诱导建立糖尿病大鼠模型,随机分为糖尿病组、低剂量骨化三醇治疗组（低剂量组,0.03μg/kg）、高剂量骨化三醇治疗组（高剂量组,0.10 μg/kg）,每组各15只.选取健康同龄大鼠10只作为正常对照组.治疗12周后,检测体重、血糖、尿素氮（BUN）、血肌酐（Scr）、血清IL-17、24 h尿白蛋白定量（UAlb）.处死动物后计算肾重指数（KI）;免疫组化法检测肾皮质内IL-17、肿瘤坏死因子α（TNF-α）和转化生长因子-β1（TGF-βl）的表达;光镜下观察肾脏组织形态学变化.多组间比较采用单因素方差分析.结果 （1）糖尿病组大鼠BUN、Scr、UAlb均较对照组显著上升[分别为（16.1±1.6）比（6.9±1.8） mmol/L,（75±11）比（46±9）μmol/L,（1.14±0.13）比（0.45 ±0.ll）mg/24 h,t=12.627、7.534、12.762,均P＜0.05],而经骨化三醇干预后上述生化指标显著改善[低剂量组分别为（12.1±1.5） mmol/L、（58±8） μmol/L、（0.86±0.10） mg/24 h].（2）糖尿病组大鼠血清IL-17、肾皮质内IL-17水平（吸光度）均较正常对照组显著上升[分别为（510±47）比（133±22） ng/L,（164±9）比（82±4）,t=17.244、20.757,均P＜0.05],而骨化三醇干预后显著改善,且高剂量组[（253±27） ng/L、119±5]较低剂量组[（324±35） ng/L、132±5]改善更显著,差异均有统计学意义（t=3.379、3.615,均P＜0.05）.（3）光镜下显示正常对照组肾脏结构未见异常,糖尿病组肾脏系膜细胞增生及系膜基质增多,并可见近端肾小管上皮细胞空泡样变性,骨化三醇组肾脏病理较糖尿病组明显改善.结论 骨化三醇对糖尿病肾脏有保护作用,其机制可能是通过上调糖尿病大鼠血清及肾皮质内IL-17的表达.

Objective To investigate the effect of calcitriol on the expression of interleukin-17 （IL-17） in kidney of diabetic rats.Methods A total of forty-five healthy eight-week-old male SD rats were treated with streptozotocin （STZ）.The STZ-induced diabetic rats were randomly divided into 3 groups：diabetic group,low-dose calcitriol （group L） and high-dose calcitriol （group H）.Another 10 healthy SD rats were considered as normal control （NC） group.After 12 weeks,body weight,blood glucose （BG）,blood urea nitrogen （BUN）,serum creatinine （Scr）,serum IL-17 and 24-hour urine albumin （UAlb） were detected.Kidney weight/body weight ratio （KI） of rats was calculated.The expressions of IL-17,tumor necrosis factor-α（TNF-α） and transforming growth factor-β1 （TGF-β1） in kidney cortex were detected by immunohistochemistry.Pathological changes in kidneys were observed by light microscope.One-way ANOVA was used for data analysis.Results （1） The serum BUN,Scr and UAlb were significantly higher in diabetic group than those in NC group （（16.1 ± 1.6） mmol/L vs （6.9 ± 1.8） mmol/L,（75 ± 11） vs （46 ±9） μ mol/L,（1.14 ±0.13） vs （0.45 ±0.11） mg/24 h,t =12.627,7.534,12.762,respectively,all P ＜ 0.05）,and those in group L and group H were decreased compared with model group （the serum BUN,Scr and UAlb in group L were （12.1 ± 1.5） mmol/L,（58 ± 8） μmol/L and （0.86 ± 0.10） mg/24 h,respectively）.（2）The serum IL-17,expressions of IL-17 in kidney cortex were significantly higher in model group than those inNCgroup（（510±47） vs（133 ±22）ng/L,（164±9） vs （82±4）,t =17.244,20.757,respectively,all P ＜ 0.05）,and those in group H （（253 ± 27） ng/L,119 ± 5） were significantly lower than in group L（（324 ± 35） ng/L,132 ± 5,t =3.379,3.615,respectively,all P ＜ 0.05）.（3） Observation by light microscope showed renal tissue of rats from NC group was almost normal,the pathological changes of rats from model group were demonstrated by the increasing of mesangial cells and matrix area in renal glomerulus,vacuolar degeneration of renal tubular epithelial cells.Pathological changes in kidneys were improved in Group L and Group H.Conclusions Calcitriol is effective in improving the reduction of the serum IL-17 and expressions of IL-17 in kidney cortex in diabetic rats.It suggests that calcitriol may protect the kidneys of diabetic rats via regulating expression of IL-17.