| Exercise-induced fatigue can be divided into central fatigue and peripheral fatigue. The central fatigue is related to protective restraints of central nervous system. A large amount of nerve impulse reaches the nerve cell with corresponding cortex while working, make it long-term excited, the ones that have caused and "consumed" increased. In order to avoid consuming excessively, protective restraints are produced when consuming to certain extent and 5-hydroxytryptamine (5-HT) of the central nervous system participate in such tired production. Chinese medicine has certain function to improve endurance performance and eliminate fatigue. The purpose of this study lies in discussing the molecular mechanism of exercise-induced fatigue and the effects of Chinese medicine through observing the effects of semen astragali complanati on contents of 5-HT and related substance and the expressions of tryptophan hydroxylase (TPH) and monoamine oxidase A (MAO-A) mRNA in rat brain with sport fatigue.The methods: 72 male SD rats were randomly divided into 4 groups. They are Sedentary Group, Model Group, Drill Group and Treatment Group. They were given 7 weeks of endurance treadmill training (speed from 15m/min gradually increased to 32m/min, 20 to 30 min/d duration with the slope at 0 degree). Free amino acids in serum, hippocampus and diencephalon were tested by amino acid automatic analytical instrument, the concentration of 5-hydroxytryptophan (5-HTP), 5-HT, 5-hydroxyindole acetic acid (5-HIAA) were tested by high performance liquid chromatography with fluorescence detection and the gene expression of TPH, MAO-A were tested by RT-PCR.The results showed: 1) The content of serum branched chain amino acid (BCAA) decreased and aromatic amino acid (AAA) especially free-tryptophan (f-Trp) increased after long term treadmill exercise. Semen astragali complanati could enhance the concentration of serum BCAA and lessen the concentration of serum AAA compared with drill group. 2) The ratios of f-Trp/BCAA and AAA/BCAA in serum increased significantly after long term treadmill exercise. It is because the metabolim of blood protein was quickened during exercise and the BCAA dispelled to supply energy andthe AAA increased. Semen astragali complanati could restrain the increase, which suggested that semen astragali complanati could benefit the balance of BCAA and AAA in brain then suspend exercise fatigue. 3) The concentration of Trp in hippocampus and diencephalon of rats increased after long term treadmill exercise, semen astragali complanati could control the increase. 4) The 5-HTP and 5-HT in hippocampus and diencephalon of rats increased after treadmill exercise, which led to exercise-induced fatigue, the extent aggravated after long term high intensity treadmill exercise. It showed that the metabolism of Trp strengthed during exercise especially after long term high intensity exercise. Semen astragali complanati could reduce the concentration of 5-HT and the precursor of it compared with drill group. 5) The concentration of 5-HIAA in hippocampus and diencephalon of rats increased after moderate intensity exercise and high intensity exercise, but both showed no significant differences compared with sedentary group. We presumed that it was because the rats had adaptability after many times repeated stimulations. Semen astragali complanati could enhance the concentration of 5-HIAA compared with drill group. 6) A significant increase expression of TPH mRNA in hippocampus was observed in drill group compared with sedentary group and drill group. But the expression of TPH mRNA decreased in diencephalon after the last exercise of model group, it hints that the expression of TPH mRNA has bidirectional change in different region of brain. The expression of TPH mRNA weakened in treatment group compared with drill group, which showed that semen astragali complanati could prevent the exercise-induced central fatigue. It conferred that the reason is the concentration of TPH receptor proteins increased. 7) An increase of MAO-A mRNA in hippocampus an... |
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