The expression of angiopoietin-1 (Ang-1) and thrombospondin-1 (TSP-1) in 5/6 subtotal nephrectomy (STN) rats model, and its correlation to the renal microvasculature injury were investi-gated. Rat 5/6 STN model was established in adult male SD rats, and the sham-operated group and 5/6 STN group were set up. The renal function and histopathological changes were examined at the 1 st, 2nd, 4th, 8th and 12th week after operation. The expression of Ang-1, TSP-1 and CD31 in renal tissues was detected by using immunohistochemistry. From 2nd to 8th week after operation, Ang-1 was significantly expressed in glomeruli of rats with STN. Ang-1 staining in glomeruli of STN group was increased significantly as compared with that in sham-operated group at 4th and 8th week after operation, and subsequently decreased after the 12th week. The expression of TSP-1 was increased significantly in STN group. As compared with sham-operated group, the CD31 expression was sig-nificantly down-regulated from the 2nd week. The expression orAng-1 mRNA was detected by using RT-PCR at the same time points. The expression of Ang-1 mRNA in renal tissue of rats with STN was significantly up-regulated at the 2rid, 4th and 8th week after operation as compared with that in STN group at other time points or in sham-operated group at the same time points, while decreased evidently at the 12th week as compared with that in sham-operated group. It is concluded that there are changes in the mRNA expression of Ang-1, and the significant up-regulation of the expression of TSP-1 in renal tissue of rats with STN, which may be involved in the remnant renal microvasculature injury.