目的明确ERβ介导脱氢表雄酮(DHEA)对成骨细胞的选择性作用机制。方法构建ERβ沉默表达的pLVTHM—GFP/ERβ-shRNA质粒和ER[3高表达的pWPT-ERβ重组质粒,转染人成骨细胞系hMG63,使hMG63细胞中的ER[3沉默表达(命名为hMG63-shER[3细胞)和高表达(命名为hMG63-ERβ细胞),分别给予DHEA(1×10^-7mol/L)、加或不加入U0126、依托泊苷作用后,流式细胞仪检测细胞的增殖和凋亡情况;同时利用逆转录PCR技术检测DHEA对hMG63细胞雌激素受体亚型mRNA表达的影响。结果hMG63-ERβ和hMG63-shERβ细胞中ERβ基因的相对表达量分别比hMG63细胞升高7.39倍和降低为17%。DHEA对hMG63-shERβ、hMG63-ERβ和对照细胞hMG63细胞ER[3mRNA的表达有升调节作用,而对ERamRNA的表达无明显影响。与hMG63-shERβ细胞相比,DHEA能明显促进ER[3高表达时(即hMG63-ERβ细胞)和对照细胞hMG63的细胞增殖[增殖指数分别为(81.6±7.6)%、(75.0±5.3)%,P均〈0.05]并拮抗细胞的凋亡[凋亡率分别为(12.2±1.6)%、(14.6±1.5)%,P均〈0.01],该作用可被U0126部分阻断[增殖指数分别为(33.2±2.0)%、(41.2±2.4)%,凋亡率分别为(40.5±4.3)%、(43.3±4.1)%,P均〈0.05]。结论优势表达的ERB是介导DHEA对成骨细胞选择性作用的主要受体。
Objective To investigate the selective mechanism of dehydroepiandrosterone (DHEA) for osteoblast via ERβ. Methods High expression of ERβ in hMG63-ERβ group ( infected with pWPT- ERβ) , gene silencing of ERβ in hMC,63-shERβ group (infected with pLVTHM-GFP/ERβ-shRNA) and hMG63 group (control) were cultured and treated with 1 ×10^-7 mol/L DHEA, with or without U0126 and etoposide. The proliferation and apoptosis of hMG63 were evaluated by flow cytometry. The mRNA level of estrogen receptor subtype was detected by reverse transcription-PCR. Results The expression of ERβ in hMG63-ERβ group and hMG63-shERβ group were increased 7.39 times and decreased 17% compared with that in hMG63 group (control). DHEA could increase ERβ expression in hMG63 in each group, however, it did not influence the expression of ERa mRNA. When the level of ERβ was high, DHEA could accelerate the proliferation [ proliferation index were ( 81.6 ± 7.6 ) % in hMC,63-ERβ, ( 75.0± 5.3 ) % in hMC,63, P 〈 0. 05 ] and inhibit the apoptosis [ apoptosis rate were ( 12. 2 ± 1.6) % in hMG63-ERβ, ( 14. 6 ± 1.5 ) % in hMG63, P 〈 0. 01 ], which was blocked by U0126 [ proliferation index were (33.2 ± 2. 0) % in hMG63- ERβ, (41.2 ± 2.4) % in hMG63, apoptosis rate were (40. 5 ± 4. 3 ) % in hMG63-ERβ, (43.3 ± 4. 1 ) % in hMG63, all P 〈 0.05 ]. When the expression of ERβ was silenced, DHEA could not inhibit the apoptosis of hMG63 anymore. Conclusion DHEA selectively act on osteoblasts via the dominant expression of ERβ.