Changes and mechanisms of body function in polar environment: Research progress / 第二军医大学学报

Exploration and utilization of polar resources are important for China's "Strategy Xinjiangyu". Extreme conditions such as coldness, low pressure, low oxygen and strong ultraviolet radiation in polar environment can lead to a series of adaptive and pathological changes of the cardiovascular system, autonomic nervous system and circadian rhythm. In polar environment, the risk of cardiovascular diseases is increased, and the injury of vascular endothelial cells and the change of cardiovascular structure and function are the important mechanisms. The supplement of dietary nitrate and the use of antisympathetic drugs may be the potential preventive measures. Cold stimulation, low oxygen and ultraviolet radiation can affect the balance of autonomic nervous system, which may be the key factor of body function changes in polar workers. In addition to the extreme climate and geographical conditions, polar workers also face polar day and night which changes the circadian rhythm. Researches have shown that melatonin secretion is highly related to the circadian rhythm, suggesting that maintaining the normal secretion of melatonin may be an effective way to regulate circadian rhythm. In addition, various extreme conditions in the polar environment can also lead to respiratory, digestive and endocrine system diseases. It is necessary to clarify the adaptability, pathological changes and mechanisms of human body in polar environment, providing references for polar workers to adapt to the polar environment and polar medical research.

Influence of Hindlimb-unloading on the Morphology of Nerve Endings in Soleus Muscle Spindles / 航天医学与医学工程

Objective To investigate changes induced by hindlimb unloading in morphology of nerve endings in soleus muscle spindles.Method Hindlimb unloading model was simulated by tail suspension in female rats.Fast silver-staining was used to observe morphology of nerve endings of single muscle spindle in 7 d,14 d,21 d and 28 d tail-suspended and control rats.Result Nerve endings of muscle spindles in control rats were intact and clear,and there was no obvious abnormality in single soleus muscle spindle of 7 d tail-suspended rats.Slight fragmentation of nerve endings was observed in Equatorial Region of soleus muscle spindle in 14 d tail-suspended rats,while reduction in density and disruption of nerve endings were observed in soleus muscle spindle in 21 d tail-suspended rats.Serious degeneration and distortion of nerve endings were found in soleus muscle spindle in 28 d tail-suspended rats.Conclusion Hindlimb-unloading can induce time-related changes in morphology of nerve endings of muscle spindle in rats soleus muscle.