BACKGROUND: We reported previously that diabetic glomerular nodular-like lesions were formed during the reconstruction process of mesangiolysis. However, the precise mechanism has yet to be elucidated. Here, we investigated the roles of matrix metalloproteinase (MMP)-2, which is activated from proMMP-2 by membrane-type (MT)-MMP in the sclerotic and endothelial cell injury process of a type II diabetic model, Otsuka Long-Evans Tokushima Fatty (OLETF) rats. METHODS: Monocrotaline (MCT) or saline only was injected three times every 4 weeks in 36-week-old OLETF rats and control Long-Evans Tokushima Otsuka rats. Glomerular expression and enzymatic activity of MMP-2 and MT1-MMP were assessed by immunohistochemistry, gelatin zymography of cultured glomerular supernatants, in situ enzymatic detection and reverse transcription-polymerase chain reaction. RESULTS: Mesangial matrix increased in OLETF rats. In addition, mesangiolysis and nodular-like mesangial expansion were observed only in MCT-injected endothelial injured OLETF rats. MMP-2 and MT1-MMP proteins increased in the expanded mesangial lesions in OLETF rats. Gelatin zymography revealed an increase in 62-kDa activated MMP-2 in the culture supernatants of isolated glomeruli from OLETF rats. In situ enzymatic activity of MMP in the mesangial areas was also detected in 50-week-old MCT-injected OLETF rats. CONCLUSION: These results suggest that MMP-2 and MT1-MMP are produced and activated in glomeruli through the progression of diabetic nephropathy and may have some effect on the remodeling of the glomerular matrix in diabetic nephropathy.
BACKGROUND: We reported previously that diabetic glomerular nodular-like lesions were formed during the reconstruction process of mesangiolysis. However, the precise mechanism has yet to be elucidated. Here, we investigated the roles of matrix metalloproteinase (MMP)-2, which is activated from proMMP-2 by membrane-type (MT)-MMP in the sclerotic and endothelial cell injury process of a type II diabetic model, Otsuka Long-Evans Tokushima Fatty (OLETF) rats. METHODS:Monocrotaline (MCT) or saline only was injected three times every 4 weeks in 36-week-old OLETFrats and control Long-Evans Tokushima Otsukarats. Glomerular expression and enzymatic activity of MMP-2 and MT1-MMP were assessed by immunohistochemistry, gelatin zymography of cultured glomerular supernatants, in situ enzymatic detection and reverse transcription-polymerase chain reaction. RESULTS: Mesangial matrix increased in OLETFrats. In addition, mesangiolysis and nodular-like mesangial expansion were observed only in MCT-injected endothelial injured OLETFrats. MMP-2 and MT1-MMP proteins increased in the expanded mesangial lesions in OLETFrats. Gelatin zymography revealed an increase in 62-kDa activated MMP-2 in the culture supernatants of isolated glomeruli from OLETFrats. In situ enzymatic activity of MMP in the mesangial areas was also detected in 50-week-old MCT-injected OLETFrats. CONCLUSION: These results suggest that MMP-2 and MT1-MMP are produced and activated in glomeruli through the progression of diabetic nephropathy and may have some effect on the remodeling of the glomerular matrix in diabetic nephropathy.
Authors: Ratnadeep Basu; Jiwon Lee; Zuocheng Wang; Vaibhav B Patel; Dong Fan; Subhash K Das; George C Liu; Rohan John; James W Scholey; Gavin Y Oudit; Zamaneh Kassiri Journal: Am J Physiol Renal Physiol Date: 2012-08-15