Significance of u-PA and PAI-1 expression on diseased glomeruli

Purpose: To investigate the significance of u-PA and PAI-1 expression in various types of glomerulonephritis. Methods: The expression level of u-PA, PAI-1, type-IV collagen and PCNA positive nuclei in 120 cases of renal biopsies from patients with various types of glomerulonephritis were detected by immunohistochemical method. Both the staining intensity of u-PA and PAI-1 in glomeruli were quantitatively analyzed by image analysis. Results: The expression intensity of u-PA and PAI-1 was different in varous types of glomerulonephritis, which were significantly higher than that of the minor lesion group. Meanwhile, the intensity of PAI-1 stain was significantly higher than that of u-PA in various types of glomerulonephritis (P<0.05). The increase of u-PA expression was closely related to increase of type-IV collagen synthesis and hypercellularity in glomeruli(r = 0.761 and 0.811, P < 0.05), while the expression of PAI-1 was closely related to the increase of Col-IV synthesis other than the cell proliferation in the glomeruli. Conclusions: The over expression of u-PA and PAI-1 may play an important role in contributing to the pathogenesis and development of glomerulonephritis.