Saadeldin Islam M, Swelum Ayman Abdel-Aziz, Elsafadi Mona, Mahmood Amer, Alfayez Musaad, Alowaimer Abdullah N
Department of Animal Production, College of Food and Agricultural Sciences, King Saud University, 11451 Riyadh, Kingdom of Saudi Arabia; Department of Physiology, Faculty of Veterinary Medicine, Zagazig University, 44519 Zagazig, Egypt.
Department of Animal Production, College of Food and Agricultural Sciences, King Saud University, 11451 Riyadh, Kingdom of Saudi Arabia; Department of Theriogenology, Faculty of Veterinary Medicine, Zagazig University, 44519 Zagazig, Egypt.
J Therm Biol. 2018 May;74:47-54. doi: 10.1016/j.jtherbio.2018.03.014. Epub 2018 Mar 15.
The dromedary camel (Camel dromedarius) is physiologically well adapted to life in hot, dry and barren land. In the present study, we report the tolerance of camel oocytes and cumulus cells to acute and chronic heat shock. Camel oocytes and cumulus cells were exposed to acute (45 °C for 2 h) and chronic (45 °C for 20 h) heat shock. Our results demonstrated that acute and chronic heat shock altered malondialdehyde concentration, which is a marker for oxidative stress. Furthermore, the heat shock reduced glutathione levels during in vitro oocyte maturation. The expression of two well-known heat shock proteins HSP70 and HSP90 were increased similarly in oocytes and cumulus cells after acute heat shock. Oocytes were less tolerant to the short acute heat shock, and showed decreased maturation, which leads to reduction in ooplasmic diameter and an increase in chromosomal count abnormalities. Furthermore, the pro-apoptotic genes P53 and BAX had increased expression levels, whereas for the anti-apoptotic gene such as BCL2 expression levels was decreased. On the other hand, the cumulus cells tolerated acute and chronic heat shock, as evident by the increase in HSP70 and HSP90 expression and steady expression levels of P53, BAX, and BCL2 after acute hyperthermia. Cumulus cells regained their vitality and ability to proliferate after chronic hyperthermia and showed wound healing capabilities after 9 days of chronic hyperthermia. Collectively, these results indicate the adaptive tolerance of camel somatic cells to acute and chronic heat shock, which is lethal to cells in many other mammals.
单峰骆驼（Camel dromedarius）在生理上非常适应炎热、干燥和贫瘠的土地生活。在本研究中，我们报告了骆驼卵母细胞和卵丘细胞对急性和慢性热休克的耐受性。将骆驼卵母细胞和卵丘细胞暴露于急性（45°C持续2小时）和慢性（45°C持续20小时）热休克条件下。我们的结果表明，急性和慢性热休克改变了丙二醛浓度，丙二醛是氧化应激的标志物。此外，热休克降低了体外卵母细胞成熟过程中的谷胱甘肽水平。急性热休克后，卵母细胞和卵丘细胞中两种著名的热休克蛋白HSP70和HSP90的表达同样增加。卵母细胞对短暂的急性热休克耐受性较差，成熟度降低，这导致卵质直径减小和染色体计数异常增加。此外，促凋亡基因P53和BAX的表达水平升高，而抗凋亡基因如BCL2的表达水平降低。另一方面，卵丘细胞对急性和慢性热休克具有耐受性，急性热应激后HSP70和HSP90表达增加以及P53、BAX和BCL2表达水平稳定即可证明。慢性热应激后卵丘细胞恢复了活力和增殖能力，慢性热应激9天后显示出伤口愈合能力。总的来说，这些结果表明骆驼体细胞对急性和慢性热休克具有适应性耐受性，而这对许多其他哺乳动物的细胞是致命的。
