Expression of CTGF and its role in the streptozotocin-induced diabetic rat kidney

AIM: To investigate the change of connective tissue growth factor(CTGF) expression and its role in streptozotocin-induced diabetic rat kidney. METHODS: Male SD rats were randomly divided into two groups: control(sham operated rats, group C,n=32) and diabetic rats (group DN,n=35). Rats in each group were sacrificed at 1, 2, 4, and 8 weeks respectively after induction of diabetes. Body weight(BW), blood glucose(BG), 24-hour urine volumn(UV), kidney weight, KW/BW,24-hour urinary albumin excretion (24Ualb), creatinine clearance (Ccr), kidney weight (KW), KW/BW, glomerular area (AG), proximal tubular area (AT) and the width of GBM、TBM at each time point were measured. Expression of CTGF and α-SMA were detected by immunostaining. RESULTS: There was a significant increase of 24 h Ualb, Ccr, KW/BW, AG, VG and the expression of CTGF in glomeruli and tubuli from week 1 onward in diabetic rats compared with those in group C (P0.05, P0.01, respectively), and an increasing expression of α-SMA mainly located in dilated tubuli from week 4 was found in group DN, which was more evident at week 8 accompanied by the decrease in AT. Diabetic rats also had a significant increase in AT from week 1 onward, which peaked at week 4. CONCLUSION: In the early stage of DN, the time-dependently upregulated CTGF might mediate the renal hypertrophy, which might be associated with the subsequent tubular epithelial-mesenchymal transdifferentiation (EMT) and renal fibrosis.