Northeast Hedgehog Physiological Characteristics Of Each Season, The Spinal Cord Thoracic Nos, C-fos Expression

Nowadays heterothermic animals's hibernate mechanism is paid more and more attentions because it is not only an adaptation in response to adverse environment such as low temperature, reduced daylight etc. but also genes controlling perform their duty within existing framework. The physiological and metabolic characteristics of the Erinaceus amurensis, a classical heterothermic animal, were measured in the present study to illuminate the seasonal changes of physiological and metabolic characteristics. The distribution of NOS and expression of c-Fos in thoracic spinal cord was detected by histochemistry and immunohistochemistry to probe into their effect in hibernation. The statistical analysis was carried out using SPSS for Windows (version 13.0).The results showed as follows:1 Relative fatness of Erinaceus amurensis was higher in spring (April) and in initial hibernation (December), and it was lower in summer and autumn; that the higher relative fatness in initial hibernation provided sufficient energy for the hedgehogs to get through hibernation. The spleen mass was higher in spring and winter than that in summer and autumn, which might have some connection with its immunization and storing blood function; The gonad mass of female and male were higher in spring and summer and lower in autumn and winter which coincided with their breeding cycle.2 It met the requirement for oxygen in hibernation because the red blood cell, hemoglobin as well as hematocrit in the blood were highest in hibernation, which was a special adaptive characteristic for hibernator. That white blood cell in torpor was remarkable lower than in nonhibernating phases showed their immunity declined in hibernation. The platelet count, mean platelet volume, platelet distribution width and thrombocytocrit were the lowest in hibernation perhaps because their vascular system was rarely injured during hibernation and it was related to maintain normal blood circulation.3 The glucose concentration in the blood was lowest in summer and elevated in autumn, but began to decline in hibernation and spring. The reason for declining in hibernation was they did not ingest food for a long period. The triglyceride concentration was highest in summer and lowest in hibernation because the triglyceride was broken down to provide energy. The albumin concentration was highest in hibernation and contributed to keep blood colloid osmotic pressure; The uric acid concentration was highest in summer and lowest in hibernation which might be related to food; The alanine aminitransperase and aspartate aminotransferase concentration were higher in summer and hibernation because the hedgehog had sharp metabolism in summer while amino acid was broken down by transamination to provide energy in hibernation.4 The heart rate of the female was significant higher than that of the male in spring, summer and autumn, besides the heart rate of the Erinaceus amurensis dropped rapidly in hibernation; The rank of respiratory frequency and oxygen consumption was autumn> spring> summer> winter with no gender difference. The reasons for the seasonal changes might be as follows:in autumn they stored energy for hibernation; while in spring they were related to maintain body temperature and reproduction; in winter the hibernator reduced oxygen consumption to elevate livability, moreover most physiological activity weakened or ceased. The rank of the thermal conductance was summer> autumn> spring.> winter, The Erinaceus amurensis in autumn with thick fur and subcutaneous fat might radiate hardly, while in spring they regulated themselves to maintain body temperature with little radiation, when they entered hibernation their body temperature was close to ambient temperature so that it was hard to transfer heat. There was a significant positive correlation between the body temperature and ambient temperature in spring, summer and autumn, which indicated they could accommodate body temperature primely to accustom unfavorable circumstance.5 There were obvious seasonal changes of the expression of NOS in thoracic spinal cord. There were much expression of NOS in lateral horn and around spinal medullary canal in spring and summer; the color of the NOS was much lighter but the positive cell in ventral horn was visible in autumn; the color of the NOS was light and the number was little in winter, besides the spinal medullary canal became smaller and neurite became much less. The rank of the area of positive cell in lateral horn was spring> summer> winter> autumn, The amount of the cerebrospinal fluid and the neurometabolic might influence the radius of the canaliscentralis and the color of positive cell around it. The reason for the area of positive cell in lateral horn was higher in autumn than in winter was that NO participated in maintaining hibernation in winter.6 That the expression of c-Fos in ependyma of thoracic spinal cord in winter was higher than in spring suggested the expression of c-Fos in ependyma might participated in maintaining hibernation and arousal. The expression of c-Fos in lateral horn in hibernation was higher than in nonhibernational seasons, which suggested c-Fos might regulate visceral activity by visceral sense-movement path; The area of NOS positive cell and c-Fos positive cell changed in the same trend in spring, summer and winter which indicated NO in lateral horn induced the expression of c-fos.