| Background Since the exercise-induced immunosuppression are intricate in its causes and mechanism, it involves the coadjustment and integration of nerve, endocrine and immune system function. However, the important nerve centre - hypothalamus makes an exact, elaborate and real-time adjustment on the neuro-immuno-endocrine network in many direct and indirect adjusting loops, which is the key adjustment. Therefore, it is of great academic and practical significance for the perfect of adjust theory of neuro-immuno-endocrine network and adjust mechanism of exercise-induced immunosuppression to study the responsive and adaptive change of neurotransmitters in hypothalamus - the advanced adjusting nerve centre during the long-term incremental exercise, and to study the change of hypothalamus-pituitary neuroendocrine which is caused by the above changes.Objective When rats make long-term incremental exercise and cause exercise-induced immunosuppression, the responsive change and gradual adaptive change of important immunoloregulation neurotransmitters are observed. The orientating, qualitative and quantitative changes of ACh, DA, NE and AD neuron are observed and their change rules and correlation are discussed. All of these provide experiment basis for the perfect of neuro-immuno-endocrine network adjusting theory.Method 72 SD female rats make a long-term incremental exercise on a uniform velocity plate with 0 slopes, 30 minutes once, once a day, and six days a week for 6 weeks. After one week adaptive training, the initiatory load is set as 20m/min and incremental load per week as 5m/min. Then the load amounts to 40m/min till the 6th week. In the 0 week, 2nd, 4th, and 6th weeks, after being filled with 4% paraform at every pore, the rats' brains are taken in separate states of control (quiescence), immediateness and 3 hours after exercises. Then the consecutive paraffin sections in coronary stations are cut and Nissle staining and immunohistochemistry staining are performed on the brain sections. The indexes of ACh, DA, NA AND AD are measured. The expression of neurotransmitter is reflected by two key parameters as AP and RI of positive neuron.Result1. The responsive change of ACh expression in hypothalamus arcuate nucleus is followed: compared with that of control state, the ACh expression of immediateness and 3 hours after exercises decreases after 2nd and 4th weeks (P＞0.05). Its adaptive change is that: compared with that of the basic level of 0 week, the Ach expression after 2 weeks changes little (P＞0.05) while that after 4 weeks decreases significantly (P＜0.05) and that after 6 weeks tends to increase to the level of 0 week (P＞0.05) with the dispersal tendency of neuron.2. The responsive change of DA expression in hypothalamus arcuate nucleus is followed: compared with that of control state, the DA expression of immediateness holds the line on the whole while the DA expression of 3 hours after exercises at the end of 2 and 6 weeks decreases significantly (P＜0.05). Its adaptive change is that: compared with that of the basic level of 0 week, the DA expression after 2, 4 and 6 weeks tends to increase gradually (P＞0.05).3. The responsive change of NA expression in hypothalamus arcuate nucleus is followed: at the end of 0, 4 and 6 weeks, compared with that of control state, the NA expression of immediateness and 3 hours after exercises tends to increase gradually (P＞0.05). At the end of 2 weeks, the expression of immediateness-and 3 hours after exercises tends to decrease (P＞0.05). Its adaptive change is that: compared with that of the basic level of 0 week, the NA expression after 2 weeks tends to increase while that after 4 and 6 weeks tends to decrease (P＞0.05).4. The responsive change of AD expression in hypothalamus arcuate nucleus is followed: in 0 week, compared with that of control state, the AD expression of immediateness after exercise tends to increase while that of 3 hours after exercises decreases and becomes lower than the level of control state (P＞0.05). At the end of 2 weeks, the AD expression of immediateness after exercises tends to decrease and that of 3 hours after exercises decreases significantly (P＜0.05). At the end of 4 weeks, the AD expression of immediateness after exercises tends to decrease while that of 3 hours after exercises increases (P＞0.05). At the end of 6 weeks, the expression of immediateness after exercises increases significantly (P＜0.05). Although the expression of 3 hours after exercises decreases, it still keeps higher than that of control state (P＜0.05). Its adaptive change: compared with the basic level of 0 week, the AD expression after 2 weeks exercises increases significantly (P＜0.05) while that after 4 and 6 weeks exercises decreases gradually to the level of control state (P＞0.05).5. The contrastive change of ACh, NA and AD in hypothalamus arcuate nucleus is followed, compared with the basic level of 0 week, the expressions of NA, AD and ACh increase at the end of 2 weeks while the increasing scope of NA and AD is larger than that of ACh (P＞0.05). At the end of 4 weeks, these expressions decrease. And the expressions of NA and AD at the end of 6 weeks keep decreasing while that of ACh tends to increase. Moreover, the expression of ACh is larger than those of NA and AD(P＜0.05).Conclusion1. The ACh expression of hypothalamus arcuate nucleus tends to decrease after one load exercise and during its recovery period, which may be connected with the decrease of body temperature and the increase of heart rateand blood pressure. It suggests that the excitation of HPA axis in the exercises may be mainly dominated by NA and AD. In the course of long-term load exercises, the ACh expression decreases for exercises stimulus need, and then recovers and increases to play a comprehensive role consequently.2. The DA expression of hypothalamus arcuate nucleus changes little but tends to decrease after one load exercise and during its recovery period, which may be connected with the long time path of DA change. The decrease of DA expression of hypothalamus reflects that center nerve adjust and control mechanism to balance the excessive excitement of HPA axis in the process of exercises stress. Moreover, the dominant expression of NA and AD may inhibit the DA expression, which detail effects and modes needs further study. In the course of long-term load exercises, when the body mobilizes the stress factors to keep exercises stress, it also suppresses the gonad axis and growth axis by some mechanisms of centre adjustment while the increase of DA expression of hypothalamus may be one of the mechanisms.3. The NA expression of hypothalamus arcuate nucleus changes differently in aload exercise. The effect of NA to HPA stress axis may be some relation of dose-effect, which may be connected withthe intensity of exercises stress. In a certain stress intensity, the NA expression has the effect of exciting HPA axis, and NA may effect by decreasing its tensive suppression. By contrast, in the stress intensity lower or higher than this scope the NA may effect by exciting HPA axis directly. In the long-term load exercises, The NA expression increases first and then decreases gradually, which conforms to the general change rules of body physiologic function from response to adaption.4. The change of hypothalamus arcuate nucleus AD expression of immediateness and 3 hours after a load exercise is different. AD expression changes to meet the demands of sports stimulus as much as possible. It suggests that hypothalamus AD may be the most important direct factor to stimulate the excitation of HPA axis. In the course of long-term load exercises, the AD change benefits the improvement of the stress hormone level, which helps body to achieve the most stable state.5. In the early adaptive period, the excitement of HPA stress axis is directed mainly by NA and AD. However, with the continuous adaptive development and deepening of exercises, the excitement of HPA stress axis is directed by ACh. |
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