Superoxide dismutase(SOD) provides a protective defense mechanism against potential cytotoxicity of superoxide radical in the aerobic organism. Although human skin is constantly at risk for developing acute and chronicchanges by ultraviolet radiation and phototoxic reactions with exogenous and endogenously produced photosensitizing molecules, studies on SOD in the human skin are rare.
Author assayed the level of SOD activities in 40 normal human skin specimens, which were obtained from face/neck(11 specimens), !fforearm(8 specimens), trunk(11 specimens), and lower extreinity(10 specimens). This study was to investigate changes of SOD activity by age, and sexual and regional differences of SOD activities in the normal skin.
The results were as follows:
1. Activities of total SOD, Cu,Zn-SOD and Mn-SOD were 29:83 11.90units/mg protein, 20. 538..82 units/rag protein and 9.21 4.21 units/rag protein respectively in the normal skin.
2. The changes of total SOD, Cu,Zn-SOD and Mn-SOD activities by age were similar each other, and highest in the third decade. But there were no significant differences between age groups in total, Cu,Zn-and Mn-SOD activities.
3. In sun exposed area, there were no significant differences between face/neck and forearm in SOD` activities. In unexposed area, there were also no significant differences between trunk and lower extremity in SOD activities.´ But SOD activities (total, Cu,Zn-, and Mn-SOD) in face/ neck were higher significantly than those in trunk and lower extremity(P< 0.05).
4. SOD activities in exposed area were higher significantly than those in unexposed area(P< 0.
01).
5. There were no significant differences between male and female in SOD activities.
6. In male, exposed area were significantly higher than unexposed area in SOD activities(P< 0.
05). But in female, there were no significant differences between exposed area and unexposed area in SOD activities.
These findings suggest that there are no differences in the intrinsic SOD activities by age and sex in the normal huma skin, and the differences between exposed and unexposed area are due to the induction of exogenous SOD activity by sun-light(UVR), and author supposes this study is useful to ´investigate the protective role of SOD in the clinically relevant skin condition.
|