Melanin relieves oxidative stress in adipocytes culture in vitro

Obesity is one of major health disorders that has become epidemic worldwide. Studies have demonstrated that oxidative stress and inflammation in adipose tissue is involved in obesity linked complications. The ectopic synthesis of melanin in adipocytes of obese patients has been newly discovered. It is hypothesized that there is potential role of melanin and its intermediates to ameliorate oxidative stress in adipose which may prevent the secondary complications to obesity.  This study was done to determine whether melanin interferes with the level of oxidative stress produced in adipocyte cells in culture. Adipocyte cells were cultured in vitro and exposed to high concentration of glucose oxidase to induce oxidative stress, then cells were treated with melanin for different periods. Thereafter the levels of some oxidative stress and inflammatory biomarkers such as glutathione, TNF-alpha, Malondialdehyde (MDA), and protein carbonyl were measured. It was found that when cells were exposed to glucose oxidase the level of oxidative stress increased over time as reflected by the decrease of Glutathione.  Interestingly, when melanin was added the level of oxidative stress decreased over time as reflected by increase in glutathione concentrations. It was also found that TNF-alpha decreased upon treatment by melanin but after 72 hours but not on 24 and 48 hours treatments. However, protein carbonyl and MDA appeared to be less affected by melanin treatments. These results may indicate that melanin is capable of diminishing the effects of oxidative stress on the cells at early stages probably by interfering with lipids peroxidation and production of reactive oxygen species.