Short‐term heat stress alters redox balance in porcine skeletal muscle

Abstract

Heat stress contributes to higher morbidity and mortality in humans and animals and is an agricultural economic challenge because it reduces livestock productivity. Redox balance and associated mitochondrial responses appear to play a central role in heat stress‐induced skeletal muscle pathology. We have previously reported increased oxidative stress and mitochondrial content in oxidative muscle following 12 h of heat stress. The purposes of this investigation were to characterize heat stress‐induced oxidative stress and changes in mitochondrial content and biogenic signaling in oxidative skeletal muscle. Crossbred gilts were randomly assigned to either thermal neutral (21°C; n = 8, control group) or heat stress (37°C) conditions for 2 h (n = 8), 4 h (n = 8), or 6 h (n = 8). At the end, their respective environmental exposure, the red portion of the semitendinosus muscle (STR) was harvested. Heat stress increased concentration of malondialdehyde (MDA) following 2 and 4 h compared to thermal neutral and 6 h, which was similar to thermal neutral, and decreased linearly with time. Protein carbonyl content was not influenced by environment. Catalase activity was increased following 4 h of heat stress and superoxide dismutase activity was decreased following 6 h of heat stress compared to thermal neutral conditions. Heat stress‐mediated changes in antioxidant activity were independent of altered protein abundance or transcript expression. Mitochondrial content and mitochondrial biogenic signaling were similar between groups. These data demonstrate that heat stress caused a transient increase in oxidative stress that was countered by a compensatory change in catalase activity. These findings contribute to our growing understanding of the chronology of heat stress‐induced intracellular dysfunctions in skeletal muscle.

Acute heat stress activated inflammatory signaling in porcine oxidative skeletal muscle

“…While it is likely that endotoxemia contributed to inflammatory signaling in these muscles the possibility of other mediators cannot be eliminated. For example, we also found increased oxidative stress in these tissues (Volodina et al 2017) and oxidative stress has been previously shown to lead to inflammatory signaling (Pizza et al 1998). In addition, in skeletal muscle heat stress failed to increase expression of heat shock proteins, however in intestinal samples from these animals they were elevated .…”

“…For example, we also found increased oxidative stress in these tissues (Volodina et al. 2017) and oxidative stress has been previously shown to lead to inflammatory signaling (Pizza et al. 1998).…”

“…Moreover, we found recently that 12 h of heat stress led to oxidative stress and that it has long been appreciated that oxidative stress can promote inflammatory signaling (Ambade and Mandrekar 2012). Importantly, we have recently demonstrated increased oxidative stress in these muscles (Volodina et al 2017). Given the possibility of inflammatory signaling driven by LPS and/or oxidative stress, the purpose of this investigation was to determine the extent to which inflammatory signaling was increased following short-term heat stress in skeletal muscle.…”

“…Importantly, we have recently demonstrated increased oxidative stress in these muscles (Volodina et al. 2017). Given the possibility of inflammatory signaling driven by LPS and/or oxidative stress, the purpose of this investigation was to determine the extent to which inflammatory signaling was increased following short‐term heat stress in skeletal muscle.…”

Identification of Metabonomics Changes in Longissimus Dorsi Muscle of Finishing Pigs Following Heat Stress through LC-MS/MS-Based Metabonomics Method

“…When the ambient temperature exceeds the thermoneutral zone (16 to 22 • C for growing-finishing pigs), the pigs are considered to be heat-stressed [4]. Chronic hyperthermia leads to increased oxidative stress in various cells and tissues including skeletal muscle [5,6]. The oxidative reaction induced by heat stress has a considerable influence on meat quality.…”