Abstract：OBJECTIVE: The abnormal proliferation of renal cells underlies the pathology of progressive glomerulosclerosis. Cell proliferation is regulated by cell cycle regulatory proteins. This study aims to investigate the expression of cell cycle regulatory protein p18 in renal tissues of the children with primary nephrotic syndrome (PNS), and to elucidate the relationship between p18 expression and cell proliferation. METHODS: Paraffin-embedded renal biopsy tissue sections from 39 patients with PNS [8 with minimal change disease (MCD), 15 with mesangialproliferative glomerulonephritis (MsPGN), 7 with membranoproliferative glomerulonephritis (MPGN), and 9 with focal and segmental glomerulosclerosis (FSGS)] were examined by immunohistochemical staining with anti-p18 monoclonal antibody and anti-proliferating cell nuclear antigen (PCNA) monoclonal antibody. Normal renal tissue sections from 6 nephrectomized patients with nephroma were used as controls. Possible correlation between the percentage of PCNA and p18 positive cells and their relationships with the pathological categories of PNS were evaluated. RESULTS: The percentage of PCNA positive cells ( 28.6%± 3.4%) in glomeruli of PNS patients was significantly higher than that of the controls ( 10.8%± 3.4%) (P< 0.05). The percentage of p18 positive cells ( 35.8%± 4.0%) in glomeruli of PNS patients was also significantly higher than that of the controls ( 6.0%± 1.9%) (P< 0.05). The percentage of PCNA positive cells ( 68.3%± 11.6%) in tubulointerstitium of PNS patients was significantly higher than that of the controls ( 12.6%± 2.6%) (P< 0.05) but there was no significant difference in the percentage of p18 positive cells in tubulointerstitium between the two groups. The percentages of PCNA positive cells in glomeruli of MCD, MsPGN, MPGN and FSGS were 23.6%± 4.6%, 40.2%± 5.1%, 27.5%± 3.6% and 34.6%± 5.1% respectively. There were significant differences among them (all P< 0.05). The percentage of p18 positive cells in glomeruli of MCD, MsPGN, MPGN and FSGS were 25.2%± 4.2%, 35.7%± 7.1%, 37.7%± 4.0% and 40.1%± 6.4% respectively. There were also significant differences among them (all P< 0.05). The percentage of p18 positive cells in glomeruli of PNS patients were positively correlated with the percentage of PCNA positive cells in glomeruli (r= 0.6632, P< 0.05). CONCLUSIONS: The overexpression of p18 in renal tissues of the children with PNS may promote the regression of abnormally proliferative cells in renal tissues.
MA Zu-Xiang,YI Zhu-Wen,ZHAO Wei-Ling et al. Expression of p18 in renal tissues of children with primary nephrotic syndrome[J]. CJCP, 2004, 6(5): 373-377.
