| Objectives:1.To explore the protective effect of active vitamin D on rats with diabetic nephropathy;2.To investigate whether active vitamin D and its receptors can protect diabetic nephropathy rats through PARP1/SIRT1/mTOR signaling pathway.Methods:40 SD rats were randomly divided into 10 normal control group and 30 DKD model groups.DKD rat models were established by feeding high-sugar and high-fat diet combined with low-dose STZ intraperitoneal injection.The vitamin D,irbesartan,and peanut oil groups were divided into 10 vitamin D group,10 irbesartan group,and 10 peanut oil group.After 6 weeks,all rats were sacrificed and weighed.Fasting blood glucose?FBG?was measured.The serum was separated to detect vitamin D,vitamin D receptor?VDR?,triglyceride?TG?,total cholesterol?TC?,low density lipoprotein cholesterol?LDL-C?,high-density lipoprotein cholesterol?HDL-C?,and serum creatinine.24-hour urine was collected to measure urine volume and quantify urine protein.HE staining was used to observe the pathological changes of renal tissues;RT-PCR was used to detect the expression of VDR,PARP1,SIRT1,and mTOR mRNA in kidney tissues,and Western Blot was used to detect the expressions of VDR,PARP1,SIRT1,mTOR,and p70s6k proteins and phosphorylation Level.variance Analysis was used between groups,and LSD-t test for comparison between the two groups.P<0.05 represents statistically significant differences between groups.Results:?1?Comparison of body weight?g?between groups:Compared with the normal group?472.19±32.81?,the vitamin D group?338.41±48.36?,irbesartan group?380.60±52.76?,and peanut oil group?327.59±46.72?significantly reduced.?All P values were<0.05?,there was no statistical difference between the DKD model groups;?2?Comparison of fasting blood glucose?mmol/L?between DKD model groups:The fasting blood glucose of the vitamin D group?16.29±1.81?was significantly lower than the irbesartan group?22.09 ± 2.66?and the peanut oil group?21.03±0.61??P<0.05?;?3?Comparison of vitamin D?nmol/L?content between the groups:compared with the normal group?613.32±113.74?,the vitamin D was reduced in the irbesartan group?501.33±115.38?and peanut oil?489.85 ± 46.85??P<0.05?,but the vitamin D group?625.40±107.44?was not significantly different from the normal group;?4?Comparison of vitamin D receptor?pg/ml?content among groups:The vitamin D group?249.45±41.73?was significantly higher than the peanut oil group?159.47±27.53??P<0.05?,but the irbesartan group?245.68 ±36.67?,and normal group?210.85±34.18?had no statistically significant difference with the vitamin D group?P>0.05?;?5?Comparison of serum creatinine?umol/L?between groups:Vitamin D group?93.19 ± 9.02?was significantly higher than the peanut oil group?141.55 ± 24.19??P<0.05?,but the irbesartan group?102.93 ± 11.91?had no significant difference with the vitamin D group?P>0.05?;?6?Comparison of TC?mmol/L?between groups:Vitamin D group?2.28 ± 0.44?was significantly lower than peanut oil group?3.53±1.13??P<0.05?,and there was no significant difference between irbesartan group?2.16±0.52?and vitamin D group?P>0.05?;?7?24-hour urine protein?mg/L?between groups:compared with the normal group?9.750 ±3.845?,vitamin D group?59.544±21.966?,irbesartan group?51.267±19.348?and peanut oil group?65.895±32.220?were significantly increased?P<0.05?,Compared with the peanut oil group,the vitamin D group and the irbesartan group decreased?P<0.05?,but the irbesartan group and the vitamin D group had no statistically significant difference?P>0.05?;?8?There was no statistical difference in the levels of TG?mmol/L??LDL-c?mmol/L?and HDL-c?mmol/L?among groups;?9?HE staining:HE staining was used for renal pathological changes.The results showed that the glomeruli in the normal group were regular and complete without mesangial hyperplasia;the glomeruli were slightly enlarged in the vitamin D group,and the mesangial area was not significantly enlarged;the glomerular hypertrophy and mesangium in the irbesartan group The matrix increased and the mesangial area widened;the glomerular volume of the peanut oil group shrank,and the mesangial area widened significantly compared with the irbesartan group.Compared with the DKD model group,the pathological changes in the vitamin D group were lighter.?10?The expression of VDR and SIRT1 mRNA in each groups:compared with vitamin D group?0.79± 0.05,0.25± 0.04?,irbesartan group?0.59±0.08,0.12± 0.02?and peanut oil group?0.25±0.04,0.03 ± 0.01?VDR and SIRT1 mRNA expressions were significantly reduced?P<0.05?,and the peanut oil group had the lowest content?P<0.05?;?11?The expression of PARP1 and mTOR mRNA in each groups:compared with vitamin D group?1.70 ± 0.33,4.15 ± 077?Compared with peanut oil group?4.62± 0.54,22.38± 4.31?,the expressions of PARP1 and mTOR mRNA were significantly increased?P<0.05?,while irbesartan group?2.18 ±0.37,6.70± 0.63?and vitamin D There was no significant statistical difference in the group;?12?VDR and SIRT1 protein expression between groups:compared with vitamin D group?1.019 ± 0.083,0.844±0.035?,irbesartan group?0.853 ± 0.058,0.729 ± 0.054?and peanut oil group?0.726 ± 0.056,0.623 ± 0.032?VDR and SIRT1 protein expressions were reduced?P<0.05?;?13?PARP1 protein expression between groups:Compared with the vitamin D group?0.766±0.036?,the expression of PARP1 protein in the irbesartan group?0.888±0.090?and the peanut oil group?1.087± 0.061?was significantly increased?P<0.05?,which was significantly increased in the peanut oil group?P<0.05?;?14?mTOR protein expression between groups:compared with the vitamin D group?1.019± 0.031?,the irbesartan group?1.150 ±0.044?and The expression of mTOR protein in the peanut oil group?1.315± 0.033?was significantly increased?P<0.05?,and the peanut oil group had the highest?P<0.05?;?15?p70s6k protein expression among the groups:similar to the normal group?0.247 ± 0.095?Ratio,the expression of p70s6k protein was significantly increased in the vitamin D group?0.442 ± 0.293?,the irbesartan group?0.405±0.126?,and the peanut oil group?0.936±0.290??P<0.05?,but there was no significant Statistical difference between the DKD model groups.?P>0.05?.Conclusions:1.Vitamin D can improve the levels of fasting blood glucose,blood creatinine,and 24h urine protein in diabetic kidney disease rats;2.Vitamin D and VDR may play a protective role in the kidney through the PARP1/SIRT1/mTOR signaling pathway. |
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