Hibernation is characterized by the profound decrease in body temperature and metabolism, which is thought to save energy expenditure during periods of severe climate and food shortage. The Syrian hamster (Mesocricetus auratus) is known as a facultative hibernator, unlike the ground squirrel, a seasonal hibernator. We have established the system by which the hamsters can be introduced into hibernation for the investigation throughout the year. When the hamsters are kept under the conditions of cold (5±1℃) and short photoperiod (2hr light/22 hr dark), about 80% of animals go into the state of hibernation after 7 to 20 weeks. The mean hibernation-starting period is about 15 weeks. The torpor, a quiescent state with low body temperature, of the hamsters lasts usually 2 to 5 days, and the torpor bouts are interrupted by periodic arousals. The hamsters experience repeated cycles of torpor and arousal throughout the hibernation period (ca. 2 months). This phenomenon would lead to elevation of reactive oxygen species (ROS) generation, but no apparent damages have been detected in the hamsters. To study the blood antioxidant status during arousal from hibernation in the Syrian hamster, we determined the levels of antioxidative enzymes in the blood. Superoxide dismutase (SOD) and catalase (CAT) activities increased transiently in blood during arousal. These results suggest that both SOD and CAT may play some roles in the antioxidative defense mechanism of hibernating hamsters. We have expected that the study of hibernation would be useful for the therapy for brain/heart diseases, organ transplantation and space travel etc. in the future.
抄録全体を表示