Less gelatinases is associated with apolipoprotein E accumulation in glomerulosclerosis rats

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.

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.

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).

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.