Department of Animal Science, Iowa State University, Ames, IA, USA.
Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA, USA.
J Therm Biol. 2021 Apr;97:102900. doi: 10.1016/j.jtherbio.2021.102900. Epub 2021 Mar 6.
Heat stress (HS) poses a major threat to human health and agricultural production. Oxidative stress and mitochondrial dysfunction appear to play key roles in muscle injury caused by HS. We hypothesized that mitoquinol (MitoQ), would alleviate oxidative stress and cellular dysfunction in skeletal muscle during HS. To address this, crossbred barrows (male pigs) were treated with placebo or MitoQ (40 mg/d) and were then exposed to thermoneutral (TN; 20 °C) or HS (35 °C) conditions for 24 h. Pigs were euthanized following the environmental challenge and the red portion of the semitendinosus (STR) was collected for analysis. Unexpectedly, malondialdehyde concentration, an oxidative stress marker, was similar between environmental and supplement treatments. Heat stress decreased LC3A/B-I (p < 0.05) and increased the ratio of LC3A/B-II/I (p < 0.05), while p62 was similar among groups suggesting increased degradation of autophagosomes during HS. These outcomes were in disagreement with our previous results in muscle from gilts (female pigs). To probe the impact of biological sex on HS-mediated injury in skeletal muscle, we compared STR from these barrows to archived STR from gilts subjected to a similar environmental intervention. We confirmed our previous findings of HS-mediated dysfunction in muscle from gilts but not barrows. These data also raise the possibility that muscle from gilts is more susceptible to environment-induced hyperthermia than muscle from barrows.
热应激（HS）对人类健康和农业生产构成重大威胁。氧化应激和线粒体功能障碍似乎在 HS 引起的肌肉损伤中发挥关键作用。我们假设米托醌（MitoQ）将减轻 HS 期间骨骼肌中的氧化应激和细胞功能障碍。为了解决这个问题，杂交公猪（雄性猪）接受安慰剂或 MitoQ（40mg/d）治疗，然后暴露于热中性（TN；20°C）或 HS（35°C）条件下 24 小时。环境挑战后，对猪进行安乐死，并采集半腱肌（STR）的红色部分进行分析。出乎意料的是，氧化应激标志物丙二醛浓度在环境和补充剂处理之间相似。热应激降低了 LC3A/B-I（p<0.05）并增加了 LC3A/B-II/I 的比例（p<0.05），而 p62 在各组之间相似，表明 HS 期间自噬体的降解增加。这些结果与我们之前在母猪（雌性猪）肌肉中的结果不一致。为了探究生物性别对 HS 介导的骨骼肌损伤的影响，我们将这些公猪的 STR 与之前接受类似环境干预的母猪的 STR 进行了比较。我们证实了之前在母猪肌肉中发现的 HS 介导的功能障碍，但在公猪肌肉中没有发现。这些数据还表明，与公猪肌肉相比，母猪肌肉更容易受到环境诱导的体温过高的影响。
