To explore a new approach for the treatment of renal interstitial fibrosis
(RIF), we detected the expression of matrix metalloproteinase-9 (MMP9) and vascular
endothelial growth factor (VEGF). Twenty-four male Sprague Dawley (SD) rats were
randomly divided into 2-week normal control (2NC) group, 4-week NC (4NC) group, 2-
week unilateral ureteral obstruction (2UUO) group, and 4-week UUO (4UUO) group.
We performed left ureteral ligation on UUO groups. Then, we sacrificed the rats of the
2NC group and 2UUO group at 2 weeks and the other groups at 4 weeks after the
surgery. Immunohistochemistry and western blot were applied to detect the expression
of MMP9, VEGF, fibronectin (FN), type IV collagen (Col-IV), and transforming growth
factor-β1 (TGF-β1). MMP9 levels reduced after UUO surgery. Its expression was less
in the 4UUO group than in the 2UUO group (P<0.05). The expression of VEGF, TGF-
β1, FN, and Col-IV was higher in UUO groups than in NC groups (P<0.05). The
expression of these indicators was higher in the 4UUO group than in the 2UUO group
(P<0.05). In the correlation analysis, MMP9 levels in UUO groups had a negative
correlation with the expression of TGF-β1, VEGF, Col-IV, FN, and RIF index (all
P<0.05). In UUO groups, VEGF levels had a positive correlation with the expression of
TGF-β1, Col-IV, FN, and RIF index (all P<0.05). In conclusion, with the aggravation of
RIF lesions, MMP9 levels decreased, and VEGF levels increased. Whether there is a
mutual inhibition relationship between them remains to be confirmed by further
experiments.