Tunici P, Schiaffonati L, Rabellotti E, Tiberio L, Perin A, Sessa A
Dipartimento di Scienze Precliniche L.I.T.A. Vialba, Università degli Studi di Milano, Centro di Studio sulla Patologia Cellulare, C.N.R., Italy.
Alcohol Clin Exp Res. 1999 Dec;23(12):1861-7.
In cultured cells of various origin, ethanol induces the synthesis of 70 kDa family heat shock proteins (hsp70 family), which play a role in the protection of protein traffic and secretion, as well as in cytoskeleton organization. To assess whether ethanol also can induce such genes in vivo, we studied the behavior of hsp70, hsc73, and grp78 messenger ribonucleic acids (mRNAs) and related proteins in the liver and brain of rats acutely treated with ethanol.
Overnight fasted Sprague-Dawley rats (220-250 g) were acutely treated with a low (2 g/kg body weight) or a high (5 g/kg body weight) dose of ethanol as a 30% solution in saline or an equal volume of saline (controls) by gastric intubation. Animals were killed at various times after treatments (3-72 hr). Messenger RNA levels for different members of hsp70 family (hsp70; 73 kDa heat shock cognate, or hsc73; and 78 kDa glucose-regulating protein, or grp78) were determined by Northern blot analysis and hybridization with specific complementary deoxyribonucleic acid (cDNA) probes. The amounts of related proteins were assayed by Western blot analysis with specific antibodies. Autoradiograms and fluorograms were subjected to densitometric scanning.
Ethanol (2 g/kg) caused a slight increase in hsc73 and grp78 mRNA levels only in the liver, without enhancing the amount of proteins. Ethanol (5 g/kg) increased the level of hsc73 and grp78 mRNAs and related proteins in the liver. In the brain, the amount of hsc73 mRNA was enhanced, but this did not change hsc73 protein. In addition, we observed an increase in cerebral grp78 transcript and related protein. Hsp70 gene was not induced in the examined tissues by either dose of ethanol.
Hepatic and cerebral hsc73 and grp78 genes are responsive to ethanol in vivo, and their activation may signal the cell's effort to counteract the harmful action of ethanol.
在各种来源的培养细胞中，乙醇可诱导70 kDa家族热休克蛋白（hsp70家族）的合成，这些蛋白在保护蛋白质运输和分泌以及细胞骨架组织方面发挥作用。为了评估乙醇在体内是否也能诱导此类基因，我们研究了急性乙醇处理的大鼠肝脏和大脑中hsp70、hsc73和grp78信使核糖核酸（mRNA）及相关蛋白的情况。
将过夜禁食的Sprague-Dawley大鼠（220 - 250 g）通过胃管给予低剂量（2 g/kg体重）或高剂量（5 g/kg体重）的乙醇（以30%的生理盐水溶液形式）或等体积的生理盐水（对照组）。处理后在不同时间点（3 - 72小时）处死动物。通过Northern印迹分析及与特异性互补脱氧核糖核酸（cDNA）探针杂交来测定hsp70家族不同成员（hsp70；73 kDa热休克同源蛋白，即hsc73；以及78 kDa葡萄糖调节蛋白，即grp78）的mRNA水平。用特异性抗体通过Western印迹分析测定相关蛋白的量。对放射自显影片和荧光自显影片进行光密度扫描。
乙醇（2 g/kg）仅使肝脏中hsc73和grp78的mRNA水平略有增加，而未增加蛋白量。乙醇（5 g/kg）使肝脏中hsc73和grp78的mRNA水平及相关蛋白增加。在大脑中，hsc73的mRNA量增加，但hsc73蛋白未发生变化。此外，我们观察到大脑中grp78转录本及相关蛋白增加。两种剂量的乙醇均未在检测组织中诱导hsp70基因。
肝脏和大脑中的hsc73和grp78基因在体内对乙醇有反应，它们的激活可能表明细胞在努力对抗乙醇的有害作用。
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