Hydrogen peroxide ($H_2O_2$)를 처리한 rat cardiomyoblast H9c2 cell (rat 배아심근 세포)에서 conjugated linoleic acid (CLA)의 oxidative stress 경감 효과를 연구하였다. H9c2 세포는 DMEM/F-12 배지에서 배양($37^{circ}C$, 5% $CO_2$)하였다. CLA (10, 20, 30, 40, $50{mu}M$)는 배양 6일간 H9c2 세포 증식을 거의 직선적으로 촉진하였다. 따라서 CLA ($20{mu}M$, $50{mu}M$)를 H9c2 cell에 2일간 처리한 후 $H_2O_2$ ($10{mu}M$; 각각 1시간 및 2시간 처리)의 독성을 조사한 결과 CLA ($20{mu}M$, $50{mu}M$)는 $10{mu}M$ $H_2O_2$ 1시간 처리에서 세포독성을 대조에 비해 유의성 있게 억제하였다(p<0.05). 또한 이 CLA는 apoptotic DNA 분포를 대조 세포에 비해 유의성 있게 감소 시켰다(p<0.05). 따라서 이 결과는 CLA가 $H_2O_2$에 의한 apoptosis를 억제함으로서 oxidative stress로부터 H9c2 세포를 보호한다고 사료되고, 이 CLA는 cardiac diseases를 보호할 수 있는 물질로 사용될 수 있을 것이다. 그러나 많은 연구가 수행되어야 할 것이다.
Conjugated linoleic acid (CLA) exhibits several beneficial biological activities including anticarcinogenesis and body-fat reduction. Now, we report that CLA ameliorated the oxidative stress in rat cardiomyoblast cells, H9c2, treated with hydrogen peroxide ($H_2O_2$). Cells were cultured in DMEM/F-12 media at $37^{circ}C$ with humidified atmosphere of 5% $CO_2$. The cells, cultured for 48 hrs, were seeded at a density $3.5{ imes}10^3$ cell/well in a 24 well-plate and incubated for 24 hr. Using these cells, two experiments were performed: the cytotoxicity test of CLA (10, 20, 30, 40, and $50{mu}Ms$), and the oxidative stress amelioration test of CLA (20 and $50{mu}Ms$) against cells treated with $H_2O_2$ (10 and 50 ${mu}Ms$) for 1 and 2 hrs. CLA enhanced the growth of H9c2 cells at any concentrations of CLA and at any incubation times (up to 6 days), indicating that CLA acts as a growth stimulant. No protective effect of CLA (20 and $50{mu}Ms$) was seen in cells treated $50{mu}M$ $H_2O_2$ for 1 and 2 hr, but these CLA concentrations ameliorated (p<0.05) the adverse effect of $10{mu}M$ $H_2O_2$ in cells treated for 1 hr. These CLA concentrations significantly (p<0.05) reduced the proportion of apoptotic cells, relative to control cells. These results suggest that CLA protected H9c2 cells from the oxidative stress of $H_2O_2$ through the suppression of cell apoptosis and could be a useful compound for the prevention of cardiac diseases caused by oxidative stress.
