| Objective:The aim of the study was to investigate the effect and mechanism of over-training on the morphosis of the small intestinal mucosa in rats,and to research the intervention and mechanism of glutamine or soy protein isolate supplementation on the morphosis in rats with overtraining.Methods:41 healthy male SD rats were randomized to divide into four groups, including the control group (C group, n=11), the heavy-load training group ( HT group, n=10), the Gln intervention group (HT+Gln, n=10) and the SPI intervention group (HT+SPI, n=10) . The rats in HT group were submitted to exhaustive training for for 9 weeks, 6 times every week.The exercise time in the Gln intervention group and SPI intervention group was mean value in HT group. The intervention groups were supplemented separately with Gln(1.5g.kg-1 body weight) or SPI ( 0.5g.kg-1 body weight) before training for each time. 9 weeks later, plasma endotoxin concentration, Hb, serum testosterone(T) and cortisone (C) concentration and the ratio of T/C , as well as Gln, MDA concentration, SOD activity in small intestines tissue were examined, and the morphosis and ultrastructure of small intestine mucosa were observed.Result:①Compared with the control group, in the HT group, serum testosterone concentration reduced obviously, serum cortisone concentration elevated obviously, which induced the ratio of T/C to reduce obviously. Hb concentration and WBC count in the blood reduced obviously. In the Gln Supplemention group, Hb, serum testosterone concentration and the ratio of T/C elevated and serum cortisone concentration reduced significantly. In SPI intervention group, Hb, serum testosterone concentration increased obviously, but serum cortisone concentration and ratio of T/C were not significant change.②Comparesd with the control group, plasma endotoxin concentration in the HT group increased obviously (P <0.01). Although the plasma endotoxin concentration in the SPI intervention group was significantly higher than that in the Gln intervention group (P <0.01), the plasma endotoxin concentration both in the Gln intervention group and in the SPI intervention group were obviously lower than those in the HT group (P <0.01).③Compared with the control group, in the HT group, the arrangement of intestinal villus was disordered, the average height of villus had a decrease tendency, but the difference was not remarkable. Villus number drceased remarkably (p <0.01). Compared with the HT group, the arrangement of intestinal villus in the Gln intervention group and the SPI intervention group was still neat, the number and length had some increases, but they didn't have a significant difference.④Under the electron microscope, the microvillus arrangement in the surface of epithelial absorptive cell in the control group was close, rule and neat, the number of mitochondrion and rough endoplasmic reticulum in the cytoplasm were rich, and their morphosis was normal. The epithelial connection was normal. In the control group, the microvillus arrangement of epithelial cell in small intestine mucosa was disordered significantly, and the mitochondrion had the degeneration extremely, forming structure as myelin sheath. The morphosis of rough endoplasmic reticulum was normal basically, and the gap of epithelium cells was broaden. Meanwhile, there were some inflammatory cells infitrated in the disordered microvillus. In Gln intervention group, the microvillus arrangement of epithelial cell in small intestine mucosa was neat and close basically. The quantity of rough endoplasmic reticulum in the cytoplasm increased obviously, and massive cystids was in its neighbor.The mitochondrion was rich, and their morphosis was normal, spreadimg around the cell nucleus.The connection of epithelial cells was close and normal. In the SPI intervention group, the microvillus morphosis of epithelial cell in small intestine mucosa was fundamental rule, the mitochondrion and rough endoplasmic reticulum in cytoplasm were rich, and their morphosis was normal basically. The endoplasmic reticulum in cells near capillary was more rich and cystids in cytoplasm increased. Connection of epithelium cells was close.⑤Compared with C group, the Gln content in small intestine in the HT group and the SPI intervention group was obviously reduced. Compared with the HT group, the Gln content in intestines in the Gln intervention group increased obviously (P <0.01), the Gln content in small intestine in the SPI intervention group reduced, but there was not significant difference.⑥Compared with C group, the MDA content in small intestine in the HT group increased obviously, SOD activity decreased remarkably (P <0.01). Compares with the HT group, the MDA content in Gln intervention group decreased remarkably (P <0.05). SOD activity elevated, but it didn't have significance difference. The MDA content in intestines in the SPI intervention group reduced obviously (P <0.05), and the SOD activity elevated obviously (P <0.01) .Conclusion:①The rat model of over-training established in this research was successful. During training, supplementation with Gln or SPI might effectively prevent the occurrence of overtraining.②Over-training might increase the permeability of the small intestine mucosa in rats, but during training, supplementation with Gln or SPI had a influential role on maintaining the permeability of the small intestine mucosa .③Over-training might cause small intestine mucosa to atrophy and the intestines epithelial cell to damage, but supplementation with Gln or SPI during training to a certain extent might prevent the atrophy of small intestine mucosa and the damage of intestine epithelial cell effectively.④Over-training might cause the Gln content to reduce and the oxygen free radical metabolism to enhance in the small intestine, which possibly was the pathologic mechanism of the increase permeability and athophy of small intestine mucosa, and damage of intestine epithelial cell.⑤During training, supplemention with Gln can maintain the morphosis of small intestine mucosa by maintaining Gln content in small intestine and increasing the ability to resist oxidation possibly, but supplementation with SPI could maintain the morphosis of small intestine mucosa by increasing the ability to resist oxidation only. |
PDF Full Text Request