Blake M J, Fargnoli J, Gershon D, Holbrook N J
Laboratory of Molecular Genetics, National Institute on Aging, Baltimore, Maryland 21224.
Am J Physiol. 1991 Apr;260(4 Pt 2):R663-7. doi: 10.1152/ajpregu.1991.260.4.R663.
An age-related impairment in the induction of heat-shock proteins (HSPs), which are thought to comprise a protective or adaptive response to cellular stress, may contribute to a reduction in thermal tolerance with age. When 5- and 24-mo-old rats were exposed to ambient temperatures of 23, 35, 37.5, or 40 degrees C for 90 min, a graded increase in the level of HSP70 mRNA expression was observed in brain, lung, and skin of animals from both groups. However, at temperatures above 23 degrees C, HSP70 expression was less in tissues of older rats when compared with those of young animals. This relative decline of heat-induced HSP70 mRNA levels with age correlated with an attenuated increase in colonic temperature (Tc) of old rats resulting from heat exposure. In other experiments, it was determined that the duration of hyperthermia was also an important factor in determining the level of HSP70 mRNA expression in vivo. Thus age-related differences in heat-induced HSP70 mRNA expression appear to result from differences in Tc due to heat stress rather than an impairment in the regulation of HSP70 gene expression.
热休克蛋白（HSPs）的诱导存在与年龄相关的损伤，热休克蛋白被认为构成了对细胞应激的一种保护或适应性反应，这种损伤可能导致热耐受性随年龄增长而降低。当将5月龄和24月龄的大鼠暴露于23、35、37.5或40摄氏度的环境温度下90分钟时，在两组动物的脑、肺和皮肤中均观察到HSP70 mRNA表达水平呈分级增加。然而，在高于23摄氏度的温度下，与年轻动物相比，老年大鼠组织中的HSP70表达较少。热诱导的HSP70 mRNA水平随年龄的这种相对下降与热暴露导致的老年大鼠结肠温度（Tc）升高减弱相关。在其他实验中，确定热疗持续时间也是决定体内HSP70 mRNA表达水平的一个重要因素。因此，热诱导的HSP70 mRNA表达的年龄相关差异似乎是由热应激导致的Tc差异引起的，而不是HSP70基因表达调控受损所致。
