Effects of both cold and heat stresses on the liver of giant spiny frog Quasipaa spinosa: stress response and histological changes

Abstract

Ambient temperature-associated stress can affect normal physiological functions in ectotherms. To assess the effects of cold or heat stress on amphibians, giant spiny frogs () were acclimated at 22°C followed by exposure to 5°C or 30°C for 0, 3, 6, 12, 24 and 48 h, respectively. Histological alterations, apoptotic index, generation of mitochondrial reactive oxygen species (ROS), antioxidant activity indices and stress-response gene expression in frog livers were subsequently determined. Results showed that many fat droplets appeared after 12 h of heat stress and the percentage of melanomacrophage centres significantly changed after 48 h at both stress conditions. Furthermore, the mitochondrial ROS levels were elevated in a time-dependent manner up to 6 h and 12 h in the cold and heat stress groups, respectively. The activities of superoxide dismutase, glutathione peroxidase and catalase were successively increased with increasing periods of cold or heat exposure, and their gene expression levels showed similar changes in both stress conditions. Most tested heat shock protein (HSP) genes were sensitive to temperature exposure, and the expression profiles of most apoptosis-related genes was significantly upregulated at 3 and 48 h under cold and heat stress, respectively. Apoptotic index at 48 h under cold stress was significantly higher than that under heat stress. Notably, lipid droplets, , and might be suitable bioindicators of heat stress. The results of these alterations at physiological, biochemical and molecular levels might contribute to a better understanding of the stress response of, and perhaps amphibians more generally, under thermal stress.

iTRAQ-Based Quantitative Proteomic Analysis Reveals Toxicity Mechanisms in Chlamys farreri Exposed to Okadaic Acid

“…In the present study, the expression of both HSPs and CYP450 genes increased with the OA exposure time, supporting their roles in stress response and detoxification process to OA. The time-dependent changes in genes to OA are also in line with the result of previous studies involving other environmental stresses (Liu et al, 2018;Nguyen et al, 2018;Nie et al, 2020;Zhang et al, 2020). We hypothesize that overexpression of the HSPs gene may counteract the proteins damaged by the ROS after OA exposure, while the enhanced synthesis of CYP450 may contribute to complete the biotransformation of OA.…”

Heat Waves, the New Normal: Summertime Temperature Extremes Will Impact Animals, Ecosystems, and Human Communities

“…Those damaged molecules cause additional deleterious effects in organisms (e.g., gene expression shifts, membrane malfunction). In response to increased oxidative stress, organisms induce the expression of anti-oxidants (e.g., catalase, superoxide dismutase, glutathione peroxidases) to scavenge the reactive oxygen species (21,28,75,134). An increased anti-oxidant defense response comes at an energetic cost for organisms, further reducing available ATP beyond the reduction in mitochondrial efficiency from proton leak (28,87).…”

Thermal stress induces positive phenotypic and molecular feedback loops in zebrafish embryos

“…H. Xia et al, 2018) and of heat-induced increased IL-1β levels in adult black rockfish (Sebastes schlegelii) (Lyu et al, 2018) and zebrafish embryos (Icoglu Aksakal & Ciltas, 2018). Higher temperature stress usually triggers an upregulation of SOD1 (Liu et al, 2018;Mahanty et al, 2016). In contrast, fluctuating thermal stress in this study reduced SOD1 expression compared to the control, measured almost eight hours after the cessation of thermal fluctuations.…”