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Abnormal gene expression of matrix metalloproteinases and their inhibitor in glomeruli from diabetic rats
T Nakamura1, M Fukui, I Ebihara
1Department of Medicine, Juntendo University School of Medicine, Tokyo, Japan.
Abstract:
The steady state levels of mRNA encoding for metalloproteinase (MMP)-1, -2, -3, and -9 and tissue inhibitor of metalloproteinase (TIMP)-1 were examined in glomeruli at 4, 12, and 24 weeks after the injection of streptozocin (STZ) in rats. The mRNA levels for MMP-1 and MMP-3 decreased with age in STZ-induced diabetes. At 24 weeks after STZ injection, mRNA levels for MMP-1 and MMP-3 fell to 40% (p < 0.01) and 20% (p < 0.01), respectively, in the glomeruli of diabetic rats when compared with control rats. In contrast, mRNA levels for TIMP-1 increased significantly with age in the diabetic glomeruli and reached an 8-fold (p < 0.01) increased at 24 weeks after STZ injection. mRNA levels for MMP-2 were not altered in glomeruli from diabetic and control rats throughout the experimental period, whereas those for MMP-9 were not detected in glomeruli from either group of rats. Insulin treatment partially ameliorated the decrease in mRNA levels for MMP-1 and MMP-3 and the increase in those for TIMP-1 in the glomeruli of diabetic rats. These data indicate that abnormal gene regulation of MMPs and TIMP-1 in the glomeruli of diabetic rats may contribute to the progression of glomerular lesions and that hyperglycemia or insulin deficiency may be associated with abnormal MMPs and TIMP-1 gene regulation.
Insights
Diabetic nephropathy in rats shows altered gene expression of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinase-1 (TIMP-1). Hyperglycemia or insulin deficiency may drive these changes, potentially contributing to kidney damage.
Area of Science:
- Nephrology
- Molecular Biology
- Endocrinology
Background:
- Diabetic nephropathy is a major complication of diabetes mellitus.
- Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) play roles in tissue remodeling and extracellular matrix dynamics.
- Altered expression of MMPs and TIMPs has been implicated in various kidney diseases.
Purpose of the Study:
- To investigate the gene expression levels of MMP-1, -2, -3, -9, and TIMP-1 in the glomeruli of rats with streptozotocin (STZ)-induced diabetes.
- To determine the effect of hyperglycemia and/or insulin deficiency on MMP and TIMP-1 gene regulation in diabetic glomeruli.
- To assess the potential role of these changes in the progression of glomerular lesions.
Main Methods:
- Quantitative analysis of steady-state mRNA levels for MMP-1, -2, -3, -9, and TIMP-1 in rat glomeruli.
- Induction of diabetes in rats using streptozotocin (STZ).
- Examination of mRNA levels at 4, 12, and 24 weeks post-STZ injection, with and without insulin treatment.
Main Results:
- STZ-induced diabetes led to decreased mRNA levels for MMP-1 and MMP-3, and a significant 8-fold increase in TIMP-1 mRNA in glomeruli over 24 weeks.
- MMP-2 mRNA levels remained unchanged, and MMP-9 mRNA was undetectable in diabetic rat glomeruli.
- Insulin treatment partially reversed the observed changes in MMP-1, MMP-3, and TIMP-1 mRNA levels.
Conclusions:
- Abnormal gene regulation of MMPs and TIMP-1 in diabetic rat glomeruli may contribute to the progression of kidney damage.
- Hyperglycemia or insulin deficiency appears to be associated with dysregulation of MMP and TIMP-1 gene expression.
- These findings highlight potential molecular mechanisms underlying diabetic nephropathy.