Medubi O O, Iranloye B O, Adegoke O A
Department of Physiology, College of Medicine of the University of Lagos, P.M.B. 12003, Lagos.
Niger J Physiol Sci. 2017 Jun 30;32(1):13-20.
Stress has been acknowledged as one of the aetiologies of female reproductive dysfunction, yet the mechanismsinvolved are not totally elucidated. Based on the paucity of information on how predator-induced stress (PS) affects oestrouscycle in rats, this study was designed to investigate the effect of PS on the oestrous cycle in rats. Forty-eight (48) SpragueDawley rats were used for this study. They were randomly divided into Control and PS group. Each group was divided intofour subgroups (n=6/group) according to the phases of oestrous cycle. Stress was induced by exposing rats to cat (predator)for 60 minutes/day for 14 consecutive days. PS caused significant disruption of the oestrous cycle. In animals subjected toPS at proestrus (PS-proestrus) and oestrus (PS-oestrus), percentage occurrence of proestrus, oestrus and metestrus phaseswere significantly reduced compared with control. In animals subjected to PS at metestrus (PS-metestrus) and diestrus (PSdiestrus), percentage occurrence of oestrus phase was not significantly affected. In all animals exposed to PS, percentageoccurrence of diestrus was significantly increased regardless of the phase of first exposure compared with control.Corticosterone and prolactin levels were significantly elevated in PS groups compared with control. Progesterone wassignificantly increased in animals at diestrus phase compared with oestrus phase and respective phases in control. Oestradiolwas significantly reduced in PS group compared with control at oestrus phase but not significantly different at diestrus phase.Luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels were significantly lower in PS groups at oestrusphase compared with diestrus phase. This study shows that PS disrupts the oestrous cycle secondary to perturbation ofhormonal control of female reproduction and is influenced by the phase at first exposure to stress.
压力已被公认为女性生殖功能障碍的病因之一，但其涉及的机制尚未完全阐明。基于关于捕食者诱导应激（PS）如何影响大鼠发情周期的信息匮乏，本研究旨在探讨PS对大鼠发情周期的影响。本研究使用了48只斯普拉格-道利大鼠。将它们随机分为对照组和PS组。根据发情周期阶段，每组再分为四个亚组（每组n = 6）。通过将大鼠每天暴露于猫（捕食者）60分钟，连续14天来诱导应激。PS导致发情周期显著紊乱。在发情前期（PS-发情前期）和发情期（PS-发情期）受到PS处理的动物中，与对照组相比，发情前期、发情期和动情后期阶段的出现百分比显著降低。在动情后期（PS-动情后期）和间情期（PS-间情期）受到PS处理的动物中，发情期阶段的出现百分比未受到显著影响。在所有暴露于PS的动物中，与对照组相比，无论首次暴露阶段如何，间情期的出现百分比均显著增加。与对照组相比，PS组的皮质酮和催乳素水平显著升高。与发情期相比，动情后期阶段的动物以及对照组相应阶段的动物中，孕酮显著增加。与对照组相比，PS组在发情期的雌二醇显著降低，但在间情期无显著差异。与间情期相比，PS组在发情期的促黄体生成素（LH）和促卵泡生成素（FSH）水平显著降低。本研究表明，PS通过干扰女性生殖的激素控制继发地扰乱发情周期，并受首次暴露于应激的阶段影响。
