This is a prospective crossover study clinical trial. In the first crossover study, 20 healthy nonsmoking volunteers (25 to 40 years old) will be randomly assigned to acupuncture or control. Endothelium-dependent, FMD of the brachial artery will be measured before and after IR (15 minutes of ischemia at the level of the proximal upper arm followed by 15 minutes of reperfusion). Acupuncture will be performed from 10 minute after ischemia till the end time of reperfusion for 20 minutes. In the second single arm study, 16 volunteers are administered oral 5mg glibenclamide two hours before IR injury (n=8) or selective cox-2 inhibitor celecoxib 200mg twice a day for 5 days to know what mechanism is responsible for acupuncture effect on IR injury. FMD measurements and acupuncture intervention during IR injury are same as above mentioned.