Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China; College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China.
Mineral Nutrition Research Division, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
J Therm Biol. 2023 Feb;112:103440. doi: 10.1016/j.jtherbio.2022.103440. Epub 2022 Dec 19.
Manganese (Mn) is an essential trace element that has been shown to attenuate the adverse effects of heat stress in the heart of broiler breeders and embryos. However, the underlying molecular mechanisms involving this process remain unclear. Therefore, two experiments were conducted to investigate the possible protective mechanisms of Mn on primary cultured chick embryonic myocardial cells exposed to heat challenge. In experiment 1, the myocardial cells were exposed to 40 °C (normal temperature, NT) and 44 °C (high temperature, HT) for 1, 2, 4, 6 or 8 h. In experiment 2, the myocardial cells were preincubated with no Mn supplementation (CON), 1 mmol/L of Mn as the inorganic MnCl (iMn) or organic Mn proteinate (oMn) under NT for 48 h, and then continuously incubated under NT or HT for another 2 or 4 h. The results from experiment 1 showed that the myocardial cells incubated for 2 or 4 h had the highest (P < 0.0001) heat-shock protein 70 (HSP70) or HSP90 mRNA levels than those incubated for other incubation times under HT. In experiment 2, HT increased (P < 0.05) the heat-shock factor 1 (HSF1) and HSF2 mRNA levels as well as Mn superoxide dismutase (MnSOD) activity of myocardial cells compared with NT. Furthermore, supplemental iMn and oMn increased (P < 0.02) HSF2 mRNA level and MnSOD activity of myocardial cells compared with the CON. Under HT, the HSP70 and HSP90 mRNA levels were lower (P < 0.03) in iMn group than in the CON group, in oMn group than in iMn group; and the MnSOD mRNA and protein levels were higher (P < 0.05) in oMn group than in the CON and iMn groups. These results from the present study indicate that supplemental Mn, especially oMn, could enhance the MnSOD expression and attenuate heat shock response to protect against heat challenge in primary cultured chick embryonic myocardial cells.
锰（Mn）是一种必需的微量元素，已被证明可减轻种鸡和胚胎心脏热应激的不利影响。然而，涉及这一过程的潜在分子机制尚不清楚。因此，进行了两项实验来研究 Mn 对暴露于热应激的原代培养鸡胚心肌细胞的可能保护机制。在实验 1 中，将心肌细胞暴露于 40°C（正常温度，NT）和 44°C（高温，HT）1、2、4、6 或 8 h。在实验 2 中，心肌细胞在 NT 下用无 Mn 补充（CON）、1 mmol/L 的无机 MnCl（iMn）或有机 Mn 蛋白盐（oMn）预孵育 48 h，然后在 NT 或 HT 下继续孵育另外 2 或 4 h。实验 1 的结果表明，与其他孵育时间相比，孵育 2 或 4 h 的心肌细胞的热休克蛋白 70（HSP70）或 HSP90 mRNA 水平最高（P < 0.0001）。在实验 2 中，与 NT 相比，HT 增加了（P < 0.05）心肌细胞的热休克因子 1（HSF1）和 HSF2 mRNA 水平以及 Mn 超氧化物歧化酶（MnSOD）活性。此外，与 CON 相比，补充 iMn 和 oMn 增加了（P < 0.02）心肌细胞的 HSF2 mRNA 水平和 MnSOD 活性。在 HT 下，iMn 组的 HSP70 和 HSP90 mRNA 水平低于 CON 组（P < 0.03），oMn 组低于 iMn 组；oMn 组的 MnSOD mRNA 和蛋白水平高于 CON 和 iMn 组（P < 0.05）。本研究的结果表明，补充 Mn，特别是 oMn，可增强 MnSOD 的表达，减轻热应激反应，从而保护原代培养鸡胚心肌细胞免受热应激。
