Effects Of Advanced Glycation End Products On The Expression Of Matrix Metalloproteinase-9and Tissue Inhibitor Of Metalloproteinase-1in Human Mesangial Cells

Objective: To investigate the possible mechanism of advanced glycation endproducts(AGEs) modified bovine serum albumin induced mesangial cell extracellularmatrix accumulation in diabetic nephropathy(DN).Methods: Human mesangial cells were incubated with medium containing differentdoses of AGEs for24hours,or with AGEs (200μg/ml) for different times. MTT wasused to estimate the cell proliferation. Reverse transcription and polymerase chainreaction (RT-PCR) and western blotting assay were used to estimate the mRNA andprotein expression level of MMP-9and TIMP-1. After pre-treated with different dosesof neutralizing antibodies to RAGE and SB203580(p38MAPK special inhibitor),theHMCs were incubated with medium containing AGEs(200μg/ml).The change of theprotein expression of MMP-9and TIMP-1was detected by western blot.Results:(1) Treated with different doses(100～400μg/ml) or times(12～48h) ofAGEs,the cell proliferation rate was up-regulated as the treatment concentrationincreased and the culture time extended.(2) The protein expression of RAGE andphospho-p38MAPK was up-regulated in the HMCs treated with AGEs. MMP-9expression was significantly decreased and TIMP-1increased at both protein andmRNA levels after incubation with AGEs compared with the control group(P﹤0.05).The effects were dose and time-dependent.(3) RAGE and SB203580could inhibit thedown-regulation of MMP-9as well as the up-regulation of TIMP-1caused by AGEs.The inhibitory effect was enhanced as the treatment concentration increased.Conclusions:(1) AGEs could significantly stimulated the proliferation of culturedhuman mesangial cells.(2) AGEs could down-regulate the expression of MMP-9and up-regulate the expression of TIMP-1in HMCs.(3) The effects could be partiallyreversed by blocking RAGE or the pathway of p38MAPK, which may delay theoccurrence and development of diabetic nephropathy.