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Example of body temperature of a Syrian hamster in hibernation. (A)A 4-week body temperature recording acquired with an intraperitoneal temperature logger showing the onset of the hibernation. Note the cycle of torpor (low body temperature) and arousal (high body temperature in between torpor bouts). The ambient temperature of the climatic room was set at 5±1°C. During torpor animals cool down to near environmental temperature. (B)A single torpor-arousal cycle during hibernation, illustrating the major phases of the hibernation cycle of the Syrian hamster. Euthermic animals have a body temperature of 37°C. After the onset of torpor animals cool down to near environmental temperatures and body temperature in deep torpor is approximately 1-2° above the ambient temperature of 5°C. after several days of torpor (ranging from 1 to 6days at an ambient temperature of 5°C in Syrian hamsters) animals spontaneously rewarm to normal physiological body temperatures (arousal).

Example of body temperature of a Syrian hamster in hibernation. (A)A 4-week body temperature recording acquired with an intraperitoneal temperature logger showing the onset of the hibernation. Note the cycle of torpor (low body temperature) and arousal (high body temperature in between torpor bouts). The ambient temperature of the climatic room was set at 5±1°C. During torpor animals cool down to near environmental temperature. (B)A single torpor-arousal cycle during hibernation, illustrating the major phases of the hibernation cycle of the Syrian hamster. Euthermic animals have a body temperature of 37°C. After the onset of torpor animals cool down to near environmental temperatures and body temperature in deep torpor is approximately 1-2° above the ambient temperature of 5°C. after several days of torpor (ranging from 1 to 6days at an ambient temperature of 5°C in Syrian hamsters) animals spontaneously rewarm to normal physiological body temperatures (arousal).

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During hibernation, small rodents such as hamsters cycle through phases of strongly suppressed metabolism with low body temperature (torpor) and full restoration of metabolism and body temperature (arousal). Remarkably, the repetitive stress of cooling-rewarming and hypoxia does not cause irreversible organ damage. To identify adaptive mechanisms p...

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... B 290: 20230368 is related to (extrinsic) apoptotic pathways, suggesting this is a key mechanism activating the apoptosis pathway in arousing hamster liver. In hibernating hamster, an increase in cell damage marker abundance was found in torpid lung [22], which was rapidly reversed upon arousal. The latter is also suggested by observations in seasonal hibernators, such as the ground squirrel, who arrest cell proliferation in torpor without increased levels of cell death [7]. ...
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... In the Syrian golden hamster, lung remodeling is one of the mechanisms that provide adaptation to hibernation (Talaei et al. , 2012. Talaei et al. (2011) demonstrated that low temperature leads to considerable modification in hibernating hamster lung structure. In their study, hamsters also showed noticeable lung remodeling during torpor. ...
... Interestingly, a partial/reversible EMT has been observed in lung tissue of hibernating animals, evidenced in a study of Syrian hamster (Mesocricetus auratus) lungs that followed EMT markers throughout different stages of hibernation. They found high expression levels of TGF-β, collagen, and smooth muscle actin during early torpor which returned to normal after torpor 100 . Similarly, a study on the brains of thirteen-lined ground squirrels observed decreased epithelial markers (E-Cadherin) and an increase in EMT markers such as vimentin and Sox2 which were restored to pre-entry expression levels at the arousal stage. ...
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