RESUMO
Objective To explore the effects of 1,25-dihydroxyvitamin D3 on renal expression of TGFβ1,Smad3 and Smad7.Methods 40 Sprague-Dawley mts were randomized into 4 groups:normal control rats (group A),diabetic nephropathy group (group B),small dose 1,25-dihydroxyvitamin D treatment group (0.5 μg · kg-1 · d-1,group C) and large dose 1,25-dihydroxyvitamin D treatment group (1 μg · kg-1 · d-1,group D),each group had 10 rats.After 12 weeks,the renal function,blood glucose,glycosylated hemoglobin and the urine trace albumin content of each rats were tested.Results The biochemical indicators in group B were higher than those in group A,(t =-16.566,P ＜0.05;t =-16.949,P ＜0.05;t =-11.844,P ＜0.05;t =-19.778,P ＜0.05;t =-14.013,P ＜ 0.05).Compared with group B,the biochemical indicators and the expression of TGFβ1,Smad3 mRNA reduced in group C and group D,and the expression of Smad7 mRNA increased (F =37.892,P ＜ 0.05;F =70.068,P ＜ 0.05;F =21.95,P ＜0.05;F =77.619,P ＜0.05;F =37.670,P ＜0.05;F =1062.562,P ＜0.05;F =2463.789,P ＜0.05;F =81.745,P ＜ 0.05).There were no significant differences between group C and group D (t =0.538,P＞0.05;t =1.737,P＞0.05;t =0.671,P＞0.05;t =1.763,P ＞0.05;t =0.997,P ＞0.05;t =1.653,P ＞0.05;t=1.543,P＞0.05;t =-1.313,P ＞0.05).Conclusion 1,25-dihydroxyvitamnin D3 has protective effect on diabetic nephropathy rats model,the mechanism may be associated with inhibiting the expression of TGF β1 and Smad3,increasing the expression of Smad7.