Background: Gelatinases include matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). The abnormal expressions of gelatinases are implicated in the pathogenesis of extracellular matrix (ECM) accumulation. Apolipo-protein E (apoE) is an important plasma protein in cholesterol homeostasis and plays a key role in the progression of glomerulosclerosis (GS). We conducted this investigation to explore whether gelatinases were associated with the apoE accumulation in the pathological process of GS.
Methods: 40 Wistar rats were divided into two groups at random: sham operation group (SHO) and glomerulosclerosis model group (GS); n=20, respectively. The disease of GS was established by uninephrectomy and adriamycin (5 mg/kg) injection. At the end of 13 weeks, the 20 rats in each group were killed and the relevant samples were collected and measured.
Results: Serum total protein (TP) and serum albumin (Alb) in GS group were reduced compared to those of the SHO group (P<0.01). Compared with the SHO group, values of 24-hour urine total protein (24UTP), 24-hour urine excretion for albumin (24Ualb), blood urea nitrogen (BUN), serum creatinine (Scr) and glomerulosclerosis index (GSI) in GS group were significantly increased (P<0.01). The protein of MMP-2 or MMP-9 in the glomerulus, and mRNA expression of MMP-2 or MMP-9 in renal tissue were reduced when compared with those in SHO (P<0.01). Protein expressions of apoE, collagen IV (Col-IV), fibronectin (FN), α-smooth muscle actin (α-SMA) and transforming growth factor-β1 (TGF-β1) in the glomerulus and expression of apoE mRNA in renal tissue were significantly up-regulated in GS group when compared with those in the SHO group (P<0.01).
Conclusions: Lower expression of gelatinases is associated with the increased expression of apoE in the glomerulus, and increases the accumulation of ECM and takes part in the pathological change of GS.