Animal Production Research Centre, Hlohovecká 2, 951 41 Luzianky near Nitra, Slovakia.
J Exp Biol. 2010 Jun 15;213(Pt 12):2125-30. doi: 10.1242/jeb.040626.
The aim of the present study was to understand the interrelationships between stress, hormones and basic ovarian functions in the ovary. For this purpose, we compared the expression of markers of proliferation (PCNA, cyclin B1), of apoptosis (Bax, caspase-3) and secretory activity (release of progesterone, P(4), and insulin-like growth factor, IGF-I) in whole ovarian follicles and granulosa cells cultured in conditions of normal temperature (37.5 degrees C) and feeding (with serum), high temperature (41.5 degrees C, with serum) and malnutrition (37.5 degrees C, without serum), with and without hormones [IGF-I, leptin and follicle-stimulating hormone (FSH)]. The expression of proliferation and apoptosis markers was evaluated by SDS PAGE-western blotting whereas radioimmunoassay (RIA) measured the release of hormones. High temperature dramatically induced a reduction in both proliferation and apoptosis markers in both ovarian follicles and granulosa cells and induced a significant increase in P(4) and IGF-I release by ovarian granulosa cells but not in P(4) secretion by ovarian follicles. Serum deprivation increased accumulation of cyclin B1 but not other markers of proliferation (PCNA) and apoptosis (Bax, caspase-3) or P(4) release in ovarian follicles. On the contrary, it inhibited the expression of apoptotic marker (Bax), release of both P(4) and IGF-I but it did not affect proliferation marker (PCNA) in granulosa cells. Adding IGF-I, leptin and FSH affected proliferation, apoptosis and secretory activity of ovarian cell functions but also prevented an inhibitory effect of high temperature on the expression of Bax and PCNA and an inhibitory action of serum deprivation on PCNA in ovarian follicles. Furthermore, treatment with these hormones prevented an inhibitory action of thermal stress on Bax, PCNA, P(4) and IGF-I in ovarian granulosa cells. The present observations (1) confirm the involvement of hormones (IGF-I, leptin and FSH) in the control of proliferation, apoptosis and secretory activity of ovarian cells, (2) demonstrate for the first time that heat stress/increased temperature can induce a reduction in ovarian cell proliferation and apoptosis and an oversecretion of ovarian hormones, (3) show that malnutrition/serum deprivation can reduce both apoptosis and secretory activity of ovarian cells, (4) demonstrate the differences in the response of granulosa and other ovarian follicular cells to stresses, and (5) are the first demonstration that hormones (IGF-I, leptin and FSH) could be used for preventing the effect of stresses on ovarian cell functions.
本研究旨在探讨卵巢中应激、激素与基本卵巢功能之间的相互关系。为此，我们比较了在正常温度（37.5°C）和喂养条件下（有血清）、高温（41.5°C，有血清）和营养不良（37.5°C，无血清）下，整个卵巢卵泡和颗粒细胞中增殖标志物（PCNA、细胞周期蛋白 B1）、凋亡标志物（Bax、caspase-3）和分泌活性（孕激素 P4 和胰岛素样生长因子 IGF-I 的释放）的表达情况，以及有和没有激素[IGF-I、瘦素和卵泡刺激素（FSH）]时的表达情况。通过 SDS PAGE-免疫印迹法评估增殖和凋亡标志物的表达，放射免疫分析法（RIA）测量激素的释放。高温显著降低了卵巢卵泡和颗粒细胞中增殖和凋亡标志物的表达，并显著增加了卵巢颗粒细胞中 P4 和 IGF-I 的释放，但对卵巢卵泡中 P4 的分泌没有影响。血清剥夺增加了细胞周期蛋白 B1 的积累，但不影响其他增殖标志物（PCNA）和凋亡标志物（Bax、caspase-3）或 P4 的释放。相反，它抑制了凋亡标志物（Bax）的表达，以及 P4 和 IGF-I 的释放，但不影响颗粒细胞中增殖标志物（PCNA）的表达。添加 IGF-I、瘦素和 FSH 会影响卵巢细胞功能的增殖、凋亡和分泌活性，但也可防止高温对 Bax 和 PCNA 表达的抑制作用以及血清剥夺对卵巢卵泡中 PCNA 的抑制作用。此外，这些激素的治疗还可防止热应激对卵巢颗粒细胞中 Bax、PCNA、P4 和 IGF-I 的抑制作用。本研究结果（1）证实了激素（IGF-I、瘦素和 FSH）在控制卵巢细胞增殖、凋亡和分泌活性中的作用，（2）首次证明热应激/温度升高可导致卵巢细胞增殖和凋亡减少以及卵巢激素分泌过多，（3）表明营养不良/血清剥夺可减少卵巢细胞的凋亡和分泌活性，（4）证明了颗粒细胞和其他卵巢卵泡细胞对应激的反应存在差异，（5）首次证明激素（IGF-I、瘦素和 FSH）可用于防止应激对卵巢细胞功能的影响。
