| Budget Amount *help |
¥3,820,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2007: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2006: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
Seventy-two-kd heat-shock protein (HSP72) is one of the stress markers induced in cells under stress, such as in the case of ischemia. Recent studies have suggested that HSP72 is a "molecular chaperone" to protect cells from various kinds of stress, and that the temporal profile of HSP72 induction is related to ischemic vulnerability. In this study, we attempted to analyze the temporal profiles of HSP72 induction in keratinocytes in the shallow hair follicles and the deep hair follicles in skin flaps after various periods of transient ischemia, and we investigated the reason why there were differences in ischemic tolerance between these cells.
We used the abdominal skin flap of Wister rats, which were divided into three groups: the sham control group (n=27), the 2-hour ischemia group (n=25), and the 8-hour ischemia group (n=25). At periods of 8, 24, 48, 96 hours, and 7 days after reperfusion, we examined them for any histological changes and performed immunostaining for HSP72 and caspas
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e-3 (n=5, each time point). In addition, we performed TUNEL stain for detecting apoptosis.
As a result, the keratinocytes in the shallow hair follicles in all groups revealed positive for HSP72 through the time course, regardless of the ischemic stresses, and they were not positive for TUNEL stain. In the deep hair follicles, the cells in the sham control group revealed no immunoreactivity after the reperfusion, and they had no positive cell in TUNEL stain. In the 2-hour ischemia group, the keratinocytes gradually increased the reactivity for HSP72; consequently they also had no positive cell in TUNEL stain at all. In the 8-hour ischemia group, the reactivity for HSP72 was revealed at 8 hours after the reperfusion and suddenly decreased at 24 hour after the reperfusion; consequently they revealed positive for TUNEL stain. And they also expressed active form of caspase-3 at 8 hours after the reperfusion.
We concluded that these differences of HSP72 expression were related to the deep follicle''s vulnerability to ischemia. The 8-hour ischemia induced the disturbance of HSP72 induction only in the deep hair follicles, consequently the keratinocytes in the deep hair follicles revealed apoptosis. And this apoptosis was accompanied with the activation of caspase-3. Less
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