Expression Of Bone Morphogenetic Protein-7 (BMP-7) In The Obstructed Rat Kidney

To observe the expression of Bone Morphogenic protein - 7 in the obstructed rat kidney in unilateral ureteral obstruction (UUO) models and explore the relationship of BMP - 7 with renal tubulointerstitial lesion.Methods42 male healthy Wister rats were randomly divided into 7 groups, UUO 1day group, 3days group, 7days group, 14 days group, 21 days group , 28days group and sham - operated groups (C group) . The rats in UUO groups underwent left ureter ligation under anesthesia while Sham - operated rats had their left ureters manipulated, but not ligated. Then six rats in UUO group and one rat in C group were killed in 1 day,3 days,7days, 14 days,21days&28 days after operation separately, and left kidneys were collected. HE and Masson stains were used to evaluate the degree of pathological changes. Immunohistochemical stains were applied to measure BMP -7 and TGF - β1 expression in the kidney. Computer assisted image analysis system were used to measure the relative volume of the cortical intersititium and for the semi - quantitative analyses of im-munohistochemical study.ResultsIn HE and Masson stains, there were no pathological change in Sham - operated group ( C group). While in UUO groups the tubulointerstitial lesion become more and more severe with the obstruction time prolonged. There were tu-bular dilation and epithelial cell necrosis. The interstitial fibrosis became veryobvious at 14 days after UUO, but no obvious change happened to glomeruli. The relative volume of cortical interstitium in obstructed kidneys of UUO groups increased gradually, In immunohistochemical staining for BMP - 7, there was a transient increase in BMP -7 expression in obstructed kidney, but its expression decrease gradually with the obstruction time prolonged. On the contrary, TGF -β1 expression increased with the obstruction time prolonged and reach the peak at 21 days after obstruction and decreased slight at 28 days. There were no or slight TGF - 81 expression in C group . The expression of BMP - 7 in UUO group was negative related to the relative volume of cortical interstitium ( r = -0. 601, P < 0. 05) .It was negative related to the expression of TGF - SI ( r = -0. 569 ,P <0. 05) . The expression of TGF - β1 is positive related to the relative volume of cortical intersititium in UUO group (r =0. 864, P <0. 05).ConclusionIn UUO rats, with the obstruction time prolonged, the expression of TGF -Bl in obstructed kidney increased gradually and reach peak at 21 days, then decreased slightly, It was positive related to the degree of renal tubulointersititial lesion; the expression of BMP - 7 in obstructed kidney decreased gradually and it was negative related to the degree of renal tubulointersititial lesion.