Objective: To observe the effects of estradiol on expression of plasma membrane Ca2+-ATPase isoform 2 in inner ear of rats. Methods: Twenty-five Three-months-old female Sprague-Dawley rats were randomly and equally divided into five groups by random number table mathod,with five rats in each group. Animals in Sham group were sham-operated while others were bilateral ovariactmized. One month after modeling, the OVX groups were supplemented with estradiol (E2 group), progesterone (P group), estradiol and progesterone (E2+P group)and vehicle sesame oil (Veh group), while the Sham operation group (Sham group) was supplemented with vehicle sesame oil.All rats were sacrificed and otocysts were obtained immediately. Enzyme-linked immunosorbent assay was used to detect the changes in serum estradiol and progesterone levels of each group of rats before operation, before treatment and before sacrifice. Western blot and quantitative real-time polymerase chain reaction were used to detect the expression of total PMCA2 protein and mRNA in the inner ear of each group. Results: There was no significant difference in serum estradiol and progesterone levels among the five groups before operated(P>0.05). Before treatment, the serum estradiol and progesterone levels of rats in each group were significantly lower than those in Sham group (P<0.05). The serum estradiol level in E2 group and E2+P group was not significantly different from that in Sham group (P>0.05), while the serum estradiol level in P group and Veh group was significantly different from that in Sham group (P<0.05). The level of progesterone in P group and E2+P group was higher than that in Sham group (P<0.05), while the level of progesterone in Veh group and E2 group was lower than that in Sham group (P<0.05). Protein and mRNA expression of PMCA2 in P and Veh groups were significantly decreased compared with that of Sham group (P<0.05) while the expression levels underwent no significantly change in E2 and E2+P groups (P<0.05). Conclusion: The decrease of serum estradiol level can reduce the expression of otolith regulatory protein PMCA2 in rats, and then affect otolith metabolism, which may be an important link of estrogen affecting otolith metabolism.
目的： 观察大鼠血清雌二醇水平变化是否会影响内耳质膜钙ATP酶异构体2（plasma membrane Ca2+-ATPase isoform 2，PMCA2）的表达，探讨雌二醇对耳石调节蛋白的影响。 方法： 25只三月龄雌性Sprague-Dawley大鼠应用随机数字表法分成5组，每组5只，其中4组行卵巢切除术（ovariectomized，OVX），1组行假手术。造模1月后OVX各组分别补充雌二醇（E2组）、孕酮（P组）、雌二醇和孕酮（E2+P组）、溶剂芝麻油（Veh组），假手术组（Sham组）补充溶剂芝麻油。补充1个月后断头处死各组大鼠，取出双侧听泡。酶联免疫吸附（ELISA）方法检测各组大鼠术前、给药前、处死前血清雌二醇、孕酮水平变化；蛋白印迹杂交（Western Blot）、实时荧光定量聚合酶链反应（quantitative real-time polymerase chain reaction，qRT-PCR）方法检测各组大鼠内耳总PMCA2蛋白和mRNA的表达水平。采用SPSS 25.0软件进行统计学分析。 结果： 术前5组大鼠血清雌二醇、孕酮水平差异均无统计学意义（P值均>0.05）；给药前各OVX手术组大鼠血清雌二醇、孕酮水平均较Sham组显著降低，差异有统计学意义（P值均<0.05）；处死前E2组、E2+P组大鼠血清雌二醇水平与Sham组相比差异无统计学意义（P值均>0.05），而P组、Veh组与Sham组相比差异有统计学意义（P值均<0.05），P组、E2+P组与Sham组相比血清孕酮水平升高（P值均<0.05），而Veh组、E2组与Sham组相比孕酮水平显著下降（P值均<0.05）。与Sham组相比，P组、Veh组大鼠听泡总PMCA2蛋白和mRNA相对表达量均明显下降（P值均<0.05），而E2组、E2+P组的相对表达量无明显变化，差异无统计学意义（P值均>0.05）。 结论： 血清雌二醇水平下降可引起大鼠耳石调节蛋白PMCA2表达下降，进而影响耳石代谢，这可能是雌激素影响耳石代谢的一个重要环节。.