Progress in research of quantification of biological age / 中华流行病学杂志

Biological age has been proved to be better than chronological age to measure the real difference of aging among individuals, but no consensus has been reached in the quantification of biological age in the field of aging research. In this paper, we summarize some commonly used quantification methods of biological age and discuss the its future development.

Expression of X-linked inhibitor of apoptosis protein and caspase-3 p17 after focal cerebral ischemia/reperfusion in rats / 中国脑血管病杂志

Objective: To study the dynamic expression of X-linked inhibitor of apoptosis protein (XIAP) and caspase-3 p17 after ischemia/reperfusion (IR) in rates. Methods: Thirty male Wistar rats were divided into sham-operated, ischemia 1.5 hours and reperfusion for 6, 12, 24, 48 and 72 hours (n = 5 in each group). A model of reperfusion after 1.5 hours of focal cerebral ischemia was established with the suture method. The expression of XIAP and caspase-3p17 in brains were observed respectively by immunohistochemical method. Results: A small amount of XIAP-positive cells were observed in the non-ischemic side in the sham-operated and IR groups, but no caspase-3 p17 positive cells were observed. The XI-APpositive cells expression began to increase (P = 0. 00) at 6-hour reperfusion, it reached to the peak at 12 hours and began to decrease at 24 hours, and then it gradually returned to normal at 48 hours (P = 0.549) as compared with the sham-operated group; a small amount of caspase-3 p17 positive cells were observed at 6-hour reperfusion, they reached the peak at 24 hours and remained for 72 hours, and they were significantly more than those at 6 hours after reperfusion (P = 0.004). Conclusion: Focal cerebral ischemia may induce the expression of apoptosis-inhibiting gene XIAP and apoptosis-promoting gene caspase-3 p17 to increase transiently, and the peak time of the former expression is earlier than that of the latter.