In the present study, we aimed to investigate a protective role for resveratrol against the effects of immobilization stress on corpora lutea (CL) of mice in early pregnancy. A total of 45 early-pregnant mice were divided into no immobilization stress (NIS) group, immobilization stress (IS) group, and immobilization and resveratrol treatment (IS+RES) group (n=15). Mice were immobilized in plastic tubes (50 mL) for 3 h per day during day 1 to 7 of pregnancy. In the IS+RES group, 5 mg kg⁻¹ d⁻¹ of resveratrol was administered just prior to application of stress. We analyzed apoptotic activity in CL by Western blotting analysis (WB), transmission electron microscopy (TEM), and immunohistochemistry (IHC). Serum progesterone levels were examined with radioimmunoassay (RIA). IHC results showed that the intensity of positive staining for Bax was increased, and for Bcl-2 was decreased in CL after IS, while resveratrol treatment reversed the positive staining for Bax and Bcl-2. WB revealed that immobilization stress up-regulated the expression of Bax and caspase-9, and down-regulated Bcl-2 expression, while resveratrol treatment attenuated the effects of immobilization stress on the expression of Bax, Bcl-2 and caspase-9. According to our TEM results, apoptosis as defined by chromatin condensation was found in CL after immobilization stress, while resveratrol inhibited the apoptosis. We also demonstrated that immobilization stress decreased progesterone concentrations and ovarian expression of StAR, while resveratrol restored the concentrations of progesterone and expression of StAR back to normal. These results indicated that immobilization stress induced luteal regression while resveratrol inhibited luteal regression, suggesting that resveratrol plays a protective role on corpora lutea of mice during early pregnancy.

在本研究中，我们旨在研究白藜芦醇对固定应激对妊娠早期小鼠黄体（CL）的保护作用。总共45只早孕小鼠分为无固定应激（NIS）组，固定应激（IS）组和固定及白藜芦醇治疗（IS + RES）组（n = 15）。在怀孕的第1至7天，每天将小鼠固定在塑料管（50mL）中3小时。在IS + RES组中，5 mg kg ^-1 d ^-1在施加压力之前立即施用白藜芦醇50mg。我们通过蛋白质印迹分析（WB），透射电子显微镜（TEM）和免疫组织化学（IHC）分析了CL中的凋亡活性。用放射免疫法（RIA）检查血清孕酮水平。IHC结果表明，IS后，CL中Bax的阳性染色强度增加，而Bcl-2的染色强度降低，而白藜芦醇处理则逆转了Bax和Bcl-2的阳性染色。WB揭示固定化应激上调了Bax和caspase-9的表达，下调了Bcl-2的表达，而白藜芦醇处理减弱了固定化应激对Bax，Bcl-2和caspase-9表达的影响。根据我们的TEM结果，固定应力后在CL中发现了染色质凝聚所定义的凋亡，白藜芦醇抑制细胞凋亡。我们还证明了固定压力降低了孕激素浓度和StAR的卵巢表达，而白藜芦醇使孕激素浓度和StAR的表达恢复了正常。这些结果表明，固定压力诱导黄体退化，而白藜芦醇抑制黄体退化，这表明白藜芦醇在妊娠早期对黄体具有保护作用。