大鼠自发性高血压和心肌肥厚时热休克蛋白70基因表达的研究

EXPRESSION OF HEAT SHOCK PROTEIN 70 GENE IN SPONTANEOUSLY HYPERTENSION AND MYOCARDIAL HYPERTROPHY FO RATS

本工作采用热休克蛋白７０（ＨＳＰ７０）核酸分子杂交方法，检测了自发性高血压大鼠（ＳＨＲ）与其正常对照（ＷＫＹ）大鼠离体培养的主动脉平滑肌细胞（ＡＳＭＣ）受热刺激后以及大鼠腹主动脉缩窄后心肌肥厚时左心室ＨＳＰ７０ｍＲＮＡ的水平，并对ＳＨＲ和ＷＫＹ肝组织基因组ＤＮＡ进行了限制性酶切片断长度多态性（ＲＦＬＰ）分析。结果表明：ａ．３７℃培养的ＳＨＲＡＳＭＣ及整体ＳＨＲ肝组织ＨＳＰ７０ｍＲＮＡ的基础表达水平均低于ＷＫＹ大鼠，ＳＨＲＡＳＭＣ受热刺激（４２℃１５ｍｉｎ）后２ｈ，ＨＳＰ７０ｍＲＮＡ表达增加的程度明显大于ＷＫＹ大鼠。ｂ．大鼠腹主动脉缩后造成左室压力超负荷，左心室ＨＳＰ７０ｍＲＮＡ在压力超负荷４ｈ时已明显升高，１ｄ、２ｄ、１ｗ均维持在高水平，１ｗ后逐渐降低。ｃ．ＳＨＲ和ＷＫＹ鼠肝组织基因组ＤＮＡ经ＢａｍＨＩ酶切后，ＳＨＲＨＳＰ７０基因缺失一条约５．６ｋｂ的片段。提示：ＳＨＲＡＳＭＣ对热敏感性增加；压力负荷增加早期，左心室ＨＳＰ７０ｍＲＮＡ表达明显增加；ＨＳＰ７０基因结构异常可能与高血压发生有关。

The level of heat shock protein 7 0 messenger RNA was examined in aortic smooth muscle cells (ASMC)and hepatic tissue of Wistar-Kyoto(WKY)rats and spontaneously hypertensive rats(SHR), and the restriction fragment length polymorphism(RFLP) was also analysed hepatic DNA. It was demonstrated that:(a)the basic level of heat shock protein 70 messenger RNA in ASMC and hepatic tissue of SHR were lower than that of WKY rats. The extent of heat shock protein 7 0 messenger RNA accumulated in ASMC was higher in SHR than in WKY rats when the cells were heated by immersing the culture bottles in a water bath maintained at 42℃for l5 mintues and allowed to recover at 37℃for 2 hours.(b) Left ventricular over-load was induced by abdominal aortic coarctation of the rats. Accumulation of HSP70 mRNA was observed after 4-hour overload and maintained at high level at 1d,2d,1w and then gradually decreased afted lw.(c)In contrast with WKY rats,the BamHI restricted hepatic DNA showed that a fragment about 5. 6Kb was lost in heat shock protein 70 gene frorn hepatic DNA of SHR. The results suggest that the ASMC of SHR is more sensitive to heat stress than that of WKY rats; Transcription of HSP70 gene was induced at an early stage of cardiac hypertrophy caused by pressure overload,and the changes of heat shock protein gene sequence may be related to genetic hypertension.