| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2012: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2011: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
|
|---|
| Research Abstract |
The aim of this study was to investigate whether increased dermal oxygen tension attenuates ultraviolet (UV)-B-induced dermal angiogenesis and wrinkle formation.In experiment 1, the backs of the mice were exposed to UVB three times per week for a5-wk. To increase dermal oxygen tension, the mice were exposed to hyperoxia (90% oxygen) for 2 h immediately after each UVB irradiation. This experiment cleared that such acute UVB exposure results in wrinkle formation associated with increased cutaneousangiogenesis. However, hyperoxic exposure immediately after UVB exposure attenuates these phenomena.In experiment 2, we investigated the effects of hyperoxia on dermal aging induced by higher doses and longer periods of UVB irradiation. The backs of the mice were exposed to UVB three times per week for a 10-wk. Hyperoxic conditions could suppress increases in hypoxia-inducible factor (HIF)-1α levels, a key molecule for angiogenesis. However, UVB-induced wrinkle formation and angiogenesis were not attenuated. Activities of matrix metalloproteinases (MMP)-2 and MMP-9, which are key molecules in wrinkle formation, increased with higher-dose and longer-term UVB irradiation regardless of exposure to hyperoxic conditions. In experiment 1, MMP-2 and MMP-9 activities did not increase. These results suggest that suppression of increases in HIF-1α levels alone is insufficient to suppress wrinkle formation caused by higher doses and longer periods of UVB irradiation. Moreover, MMP-2 and MMP-9 might not play a critical role in either wrinkle formation or angiogenesis during the early stage of acute UVB-induced wrinkle formation.
|
