Role of type I plasminogen activator inhibitor in mediating renal tubulointerstitial injury of patients with IgA nephropathy

Objective To explore the role of type 1 plasminogen activator inhibitor (PAI-1 ) in mediating renal tubulointerstitial injury of patients with IgA nephropathy. Methods The mRNA and protein production of PAI-l in renal tubulointerstitium were defected using in stiu hybridization and immunohistochemistry. Detections of antigens of α-smooth muscle actin(α-SMA) and proliferating cell nucleus antigen (PCNA) were also performed. Results PAI-l was normally expressed in the walls of vessels and distal tubules, but significantly increased in lesions of IgA nephropathy, including crescents, Bowman capsules and tubulointerstitial infiltrating cells. There was lithe expression of PAl-1 in the glomerular capillary tufts. The renal expression of PAI-l was significantly correlated with serum creatinine (P 0. 01 ). PAI-1 expression was also positively correlated with the pathological parameters including tubulointerstitial infiltration, tubular atrophy and tubulointerstitial fibrosis(all P 0. 01). Besides, the renal expression of tubulointerstitial PAl-l was apparently correlated with those of α-SMA and PCNA. Conclusion PA-l may have an important role in mediating the tubulointerstitial fibrosis of IgA nephropathy.