Co-expression of MMP-9/IgA and TIMP-1/IgA in renal tissue of IgA nephropathy and its significance

Objective To study the role of immunoglobulin A（IgA） deposition in the progress of IgA nephropathy by observing the co-expression of matrix metalloproteinase-9（MMP-9）,its tissue inhibitor-1（TIMP-1） and IgA in IgA nephropathy patients with variant glomerular lesions. Methods Co-expression of MMP-9/IgA and TIMP-1/IgA in renal tissues from 56 patients with IgA nephropathy（Lee levels I-V） was detected with immunofluorescence double-staining. Results The TIMP-1/IgA was lowly expressed while the MMP-9/IgA was highly expressed in glomeruli of patients with IgA nephropathy（Lee levels I-II）.The expression level of TIMP-1/IgA was higher while that of MMP-9/IgA was lower in glomeruli of patients with IgA neprhropathy（Lee level III）.The expression level of TIMP-1/IgA was the highest while that of MMP-9/IgA was lower in glomeruli of patients with IgA nephropathy（Lee level IV-V） and the lowest in sclerotic glomeruli of patients with IgA nephropathy. Conclusion The IgA deposition and TIMP-1 expression are increased while the MMP-9 expression is decreased during the progress of IgA nephropathy,which suggests that IgA deposition-induced imbalance of MMP-9/TIMP-1 is involved in glomerular sclerosis in patients with IgA nephropathy.