[Effect of catechin microcapsule on the repair of DNA damage in glomerular mesangial cells induced by H2O2].

Objective: To explore the effect and possible mechanism of catechin microcapsulation on the repair of DNA damage in glumreular mesangial cells (GMCs) induced by H2O2.

Methods: According to H2O2 concentration, the experiment GMCs were divided into 6 groups: a control group, 50 micromol/L group, 100 micromol/L group, 150 micromol/L group, 200 micromol/L group and 250 micromol/L group. Each group was sub-divided into 3 groups: 6 h group, 12 h group and 24 h group, in order to determining the optimum dose and the best time of detecting the DNA damage in GMCs. The cultured cells were divided into 8 groups as follows: the NS control group, the H2O2 group, the catechin groups (the final concentrations were 10.0, 15.0, and 20.0 mg/L respectively) and the various catechin microcapsulation groups (the final concentrations were 10.0, 15.0, and 20.0 mg/L respectively). At the end of the experiment, hydroxy radical (OH), malonydialdehyde (MDA) and total superoxide dismutase (tSOD) concentration of supernadant in GMCs were determined by biochemistry assay, the repair of DNA damage in GMCs were detected by single cell gel electrophoresis assay.

Results: (1)At 6th h, H2O2 of 100 micromoL/L could cause the DNA damage of GMCs, and H2O2 of 150 micromol/L could result in DNA damage significantly. (2) No difference was found in the comet span of GMCs DNA in the catechin group and catechin microcapsulation group of different concentrations, while the DNA comet tail-long in the catechin microcapsulation group was shorter than that of the catechin group(all P(s)<0.05), and the fluorescence intensity of tail in the catechin microcapsulation group was lower than that of the catechin group(all P(s)<0.01). (3)When the concentration of catechin was 10.0 mg/L, no statistical significance was obtained in the concentration of dOH-, MDA and tSOD between the catechin microcapsulation group and the catechin group; while dOH- and MDA concentrations were lower, and the tSOD was higher in the catechin microcapsulation group than that in the catechin group when the concentration of catechin was 15.0 mg/L and 20.0 mg/L(all P(s)<0.05).

Conclusion: Catechin microcapsulation can enhance the GMCs ability of repairing DNA damage,which may be due to elevating the capacity of its anti-oxidation by catechin microcapsulation.