The expression of matrix metalloproteinase-12 in the peritoneum of rats with continuous peritoneal dialysis.

ABSTRACT

BACKGROUND: Peritoneal dialysis (PD) is an important alternative treatment for end-stage renal disease. Continuous exposure to non-physiological fluids during PD is associated with pathological responses, such as sustained microinflammation, leading to tissue fibrosis and angiogenesis. However, the effect of PD fluid on submesothelial cells has not yet been investigated in detail. METHODS: We investigated the association between macrophages and the expression of matrix metalloproteinase-12 (MMP-12), an elastin proteinase secreted by macrophages, in the peritoneal tissue of rats undergoing continuous PD. RESULTS: Morphological data revealed that the submesothelial layer of the peritoneum in PD model rats was markedly thickened, with fibrosis and angiogenesis. In the fibrillization area, elastin was disorganized and fragmented, and macrophages accumulated, which tended to have M2 characteristics. The expression of MMP-12 was enhanced by continuous exposure to PD fluid, suggesting that MMP-12 expression may be involved in PD fluid-induced peritoneal damage. CONCLUSIONS: The results of this study may lead to a better understanding of the mechanisms underlying fibrosis in PD.