大鼠肝脏增龄性变化和热休克蛋白70表达差异

Effects of aging on liver and heat shock protein 70 expression in rats

目的观察不同年龄大鼠肝脏的增龄性变化以及热休克蛋白70（HSP70）在肝组织中的表达，探讨HsP70在肝脏老化中的作用。方法雄性sD大鼠按月龄分为2ld组、3月龄组、12月龄组和18月龄组，每组各6只。进行常规血清学测试，光镜下观察肝组织结构，Real一timePCR法检测HSP70在各组大鼠肝组织中的表达。结果随着鼠龄增长，4组大鼠肝质量／体质量比值明显降低，分别为o．073、O．050、O．025和O．019（P=0.000）；21d组和3月龄组与12月龄组和18月龄组比较，血清白蛋白水平减低[分别为（35．O土2．7）g／L和（39．8±3．5）g／L比（27．3±9．3）g／L和（20．6±1．7）g／L，t=12．233，P=0.000]；碱性磷酸酶（ALP）水平升高[分别为（68．8土23．3）u／L和（71．6±19．2）U／L比（185．9±41．5）U／L和（418．6士140．6）U／L，t=35．354，P=O.000]。光镜下可见12月龄和18月龄大鼠的肝细胞排列紊乱，细胞内脂肪空泡明显增多。18月龄组大鼠肝细胞HsP70mRNA表达相对量（0．218），低于12月龄组（O．220）和3月龄组（O．230）（p=0.000）。结论HsP70可能参与了肝细胞老化的进程，可以作为预测肝脏老化的检测指标之一。

Objective To observe the effects of aging on liver and heat shock protein （HSP）70 expression in rats, and explore the role of HSP 70 in the changes of aging liver. Methods 24 healthy Sprague Dawley rats were divided into 4 groups according to age： 21-day-old group, 3-month- old group, 12-month-old group and IS-month-old group （n-- 6 per group）. Routine blood tests and biochemical tests were tested. Liver tissues were observed under light microscopy. The mRNA expression of HSP70 was detected by real-time PCR. Results The ratios of liver weight to body weight were decreased gradually with aging in 4 groups （0. 073, 0. 050, 0. 025, 0. 019, respectively, t=78. 016, P= 0. 000）. Compared with those of young rats （21-day-old and 3-month-old）, serum albumin levels of aged rats （12-months and 18-months） were declined （（35.04±2.7） g/L and （39.8q- 3.5） g/Lvs. （27.34-9.3） g/Land （20.6＋1.7） g/L, t=12.233, P^0.0003. Nevertheless serum alkaline phosphatase （ALP） levels were increased with aging C（68.8 4± 23.3） U/L, （71.6 4±19.2） U/L, （185.9 4±41.5） U/L, （418.6 4- 140.6） U/L, respectively, t = 35. 454, P= 0. 0003. The differences in other routine biochemical indexes were not found among the age groups （P〈 0.05）. Liver histological changes including hepatocytes disordered and vacuolization or fatty changes were detected with aging, especially in 18-month-old rats. Real-time PCR results indicated that the expression level of HSPT0 mRNA was much lower in 18-month-old rats than in 12-month-old and 3-month-old rats （0.218 vs. 0.220 and 0.230, P=0.000）. Conclusions HSP70, as a stress protein, may play an important role in the procedure of injury and senescence of liver cell, and then can serve liver aging as one of the influential markers.