[Effect of L-EGCG on lipopolysaccharide-induced glomerular mesangial cell proliferation in rats]

To determine the effect of L-epigallocatechins gallic acid ester (L-EGCG) on glomerular mesangial cells (GMCs) proliferation, and to make clear the possible mechanism.

We investigated the effect of different doses of L-EGCG on GMCs proliferation at 24 h, 48 h and 72 h respectively, and screened the best dosage and time point. GMCs were divided into 5 groups: control, L-EGCG group, LPS group, dexamethasone group, and L-EGCG plus dexamethasone group. At the end of the experiments, the cultured GMCs and its suspension were collected, the positive rate of proliferating cell nuclear antigen(PCNA) was taken count of by immunohistochemical assay, the rate of effective apoptosis of GMCs by terminal deoxynucleotidyl transferase mediated dUTP nick endlabeling (TUNEL) assay, and -OH, malonydialdehyde (MDA), superoxide dismutase (SOD) by biochemical assay.

L-EGCG of 200 mg/L had the most strong inhibitory effect on GMCs at 48 h. The levels of -OH, and MDA in the L-EGCG group was significantly lower than those in the LPS group (P < 0.01), while the level of SOD in the L-EGCG group was significantly higher than that in the LPS group (P < 0.01); the PCNA positive rate of GMCs in the L-EGCG group was significantly lower than that in the LPS group (P < 0.01), and the effective apoptosis of GMCs in the L-EGCG group were significantly higher than that in the LPS group (P < 0.01). The PCNA positive rate of GMCs was positively correlated with the level of -OH and MDA, while negatively correlated with the level of SOD.

The suppressive effect of L-EGCG on the abnormal proliferation of GMCs might be that L-EGCG could weaken the suppressive effect of -OH on the SOD activity, decrease the accumulation of MDA, and increase the apoptosis of GMCs.