ABSTRACT
AIM: To establish a model of subtotal nephrectomy (SNx) and investigate the changes of apoptosis and apoptosis-related genes (Bax, bcl-2, caspase-3, caspase-8 and caspase-9) in the rat remnant kidney. METHODS: Remnant kidneys were produced in adult male SD rats by 5/6 nephrectomy. The renal function and histopathological changes were evaluated at 1, 2, 4, 8, 12, 16, 26 and 40 weeks after operation. The tissues of remnant kidneys were collected to detect apoptosis cells by in situ end-labeling of cleaved DNA (TUNEL) and proliferating cells by determining the proliferating cell nuclear antigen (PCNA). The expression of Bax, bcl-2, caspase-3, caspase-8 and caspase-9 was measured by RT-PCR and Western blotting. The proteins were detected by immunohistochemistry staining. The relation between apoptosis, proliferation, glomerulosclerosis and renal interstitial fibrosis was also observed. RESULTS: The results showed the renal pathological dynamic changes in 5/6 nephrectomy remnant kidneys were tubule-interstitial inflammation and fibrosis, as well as glomerulosclerosis. There were transient increases in both proliferating and apoptotic processes in glomerulus, tubules and interstitium. Apoptosis was increased and most of apoptotic cells were detected in tubular epithelial cells and interstitial area. The mRNA and protein expression of Bax, caspase-3, caspase-8 and caspase-9 were increased in all course, and peaked at week 4 and 40 in the SNX rats. The successive changes of these parameters were parallel to the level of focal inflammation in interstitium. Glomerulosclerosis index was related with focal inflammation cells and 24 hours urine protein (r=0.788, 0.822; P