Effects Of Electroacupuncture On Dynorphin-A Level In The Central Nerve System Of Rats With Exercise-induced Fatigue

Exercise-induced fatigue is a frontline subject in exercise physiology, exercise medicine, exercise biochemistry as well as athletic training. The emergence of exercise-induced fatigue can be influenced by peripheral, central and many other factors. Many hypothesis such as the accumulation hypothesis, the exhaustion hypothesis, the ionic metabolic disorder theory and the internal secretion regulation theory etc., have been raised in the peripheral level to explain exercise-induced fatigue reasonably. The central nervous system was in close relation with exercise fatigue. The central fatigue can be caused by exercise, and in turn the functional disorder of the central nervous system can be an important causation of exercise fatigue. So more and more attentions are being paid to the central mechanism of exercise-induced fatigue.It was reported that the endogenous opioid peptides(EOPs) could be activated by moderate exercise. High intensity exercise can raise Dynorphin-A(DYN-A) level. The EOPs may participate in the regulation and recovery of exercise-induced fatigue. DYN-A as a member of the EOPs family has multiple physiological function and the function of DYN-A on central exercise fatigue is worth investigating. Electroacupunture(EA) is an effective and safe method to treat exercise-induced fatigue with a broad prospect of application. But it remains unclear whether EA can treat exercise fatigue through changing central DYN-A level. In this study, rats were electroacupunctured to prevent and treat the exercise-induced fatigue. The DYN-A immune activity and the biochemical indexes were determined to discuss the central mechanism of DYN-A participating in EA treatment on fatigue.Eighty four male Sprague Dawley rats aged 5 weeks, weighing 200 ± 20 g, were randomly divided into the control group(C), the exercise group(EX), the EA group(EA) and the exercise with EA group(EX+EA). Rats in the EA group were electroacupunctured in the bilateral Zusanli acupoint at 2/100 Hz for 15 min every two days from the first day on. Rats in the EX group underwent the 7-week treadmill training. Rats in the EX+EA group underwent the treadmill training and were electroacupunctured 3h after the training, and the method of exercise and EA were the same with the EX and the EA group. Rats in the C group were fed without EX or EA treatment. The adaptation and restraint of rats in the C and EX group were the same with the EA and EX+EA group. 7 rats in each group were sampled at week 5, week 6 and week 7 respectively to collect blood and to perfuse brain tissues.Biochemical reagents were used for detection of hemoglobin(HB), blood lactic acid(BLA) glucose(GLU) and blood urea nitrogen(BUN). The immune activity of DYN-A in the nucleus which included GP, CPu, ACB, ARH, NRM, PBN, NRD and SOL was determined by SABC immunohistochemistry.The results showed that HB in the EX group decreased significantly in comparison with the C group at week7(p=0.001).The content of HB in the EA group and the EX+EA group were significantly higher than the EX group at week7(p= 0.000, p=0.028). Compared with the C group, BLA in the EX group increased significantly at week 6 and week 7(p=0.007, p=0.000). The concentration of BLA in the EX+EA group decreased significantly at week7 comparing with the EX group(p=0.042).In comparison with the C group. BUN in the EX group increased significantly at week6 and week7(p<0.05). The concentration of BUN in the EA and the EX+EA group decreased significantly at week6(p=0.032) and week7(p=0.028) comparing with the EX group(p<0.05). In comparison with the C group, GLU in the EA group increased(p>0.05) at week 7 but decreased(p>0.05) in the EX groups. GLU in the EX+EA group had no obvious difference with other groups(p>0.05).Compared with the C group, DYN-A immune activity of NRM in the EX group reduced significantly(p<0.05). DYN-A immune activity of NRM and PBN in the EX+ EA group was higher than the EX group(p<0.05). DYN-A immune activity of PBN and SOL in the EX group reduced at week 6 and week 7. DYN-A immune activity of SOL in the EX+EA group was significantly higher than the EX group at week 6 and week 7(p<0.05).DYN-A immune activity of ACB、CPu and NRD in the EX and EA groupin comparison with the C group(p<0.05). DYN-A immune activity of ACB in the EX +EA group was significantly lower than the EX group. And DYN-A immune activity of CPu and NRD in the EX+EA group were lower than the EX group at week 6 and week 7(p<0.05).DYN-A immune activity of ARH and GP in the EX and EA group were higher than the C group at week 5 and week 7(p<0.05). DYN-A immune activity of ARH in the EX+EA group was higher than the EX group at week 6 and week 7(p<0.05). DYN-A immune activity of GP in the EX+EA group was higher than the EX group at week 5,6 and 7(p<0.05).The results exhibited the biochemical indexes and DYN-A immune activity of the exercise-induced fatigued rats treated by EA, which indicated that EA could decrease BUN and BLA as well as increase GLU and HB. EA can regulate the DYN-A level in ACB、GP、CPu、ARH、NRD、PBN、SOL and NRM, maintaining the dynamic level of DYN-A to adapt to exercise intensity. The result may help to clarify the endogenous mechanism of EA treatment on fatigue as well as the regulation mechanism of EOPs. It is helpful for better clinical use of EA on exercise-induced fatigue and the improvement of health and competition results.