Cold Stress-induced Impairment Of Learning And Memory Of Rats And Its Mechanism

Individuals exposed to natural or artificial cold environments may incur the reduction of the physical or mental if the intensity of cold stress is more than the limits of human tolerance. injuries which cold results in are frostbite. During the war, frostbite has became the key factor in winter war. In some winter war, frostbite accounted for half of the soliders. Therefore, it is very important to study the effect of cold environment on the strength of the army is necessary.Cold can lead to impairment in immune system, circulatory system , respiratory system, urinary system, energy metabolism. During cold environment, Individuals usually occur hypothermia, If not, cold may effect on the function of brain; such as indifference, excitablility, no concentration,ineffective working,reaction time delayed;these showed that cold exposure could influence on function of brain.However,its mechanism is unclear.The regulation of brain function plays a crucial in the adaption to cold. Hippocampus is important region of memory and learning in neural activity. while hippocampus function must have much energy. Since ERK cascade plays an important role in mammalian associative learning.In the present study ,we investigated the impacts of acute cold exposure on spatial learning and memory of rats and its mechanisms. [Method]Rats were put at -15℃for 6h. Learning and memory was detected by Y maze; The histopathological of the rat hippocampus were observed by hematoxylin and eosin staining; ATP content was detected by ATP kit;Westen blot was performed to determine the expression and phosphorylation of ERK, AKT signaling molecules.[Result]1.Y-maze showed that Cold exposure induced significant impairment of learning and memory the descent of correct number, CN: the increasing of total reaction time,TRT)2.HE staining showed that hippocampus morphological changes were significant after the cold exposure.3.ATP content showed that ATP content was decreased after the cold exposure.4.Western blot demonstrated that the cold exposure significantly decreased the level of phosphorylated ERK,AKT.[Conclusion]Cold exposure can result in the decreaing of memory and learning of rat.it showed that long time cold exposure may impair memory and learning of rat and hippocampus morphological structure; cold exposure also leads to decreased ATP content, it indicated that long time cold exposure could make energy metabolism of hippocampus dropped;At the same time,AKT-ERK signaling may be involved in it.