[Protective effects of spirulina on hippocampal injury in exercise-fatigue mice and its mechanism].

OBJECTIVE

To investigate the roles of BDNF/TrkB neurotrophic signaling in hippocampal injury for fatigue rats induced by incremental load exercise and the protective effects and mechanism of spirulina supplement.

METHODS

Sixty SD rats were randomly divided into normal control group (NC), normal plus spirulina group(NS), exercise model group (EM), exercise plus spirulina group (ES), and positive control group (PC), 12 rats in each group.Group EM, Group ES and Group PC were applied by treadmill running with high-intensity increasing for three weeks, and Group NC had not any intervention measures.Group ES and Group NS were treated with spirulina at a dose of 300 mg/kg.bw.by intragastric administration.Group PC was gavaged at the same volume of ginseng extract of 1.92 g/kg for three weeks.The expressions of brain-derived neurotrophic factor (BDNF), tyrosine kinase recptor (TrkB), phospho-tyrosine kinase recptor (p-TrkB) were tested by Western blot and immunohistochemical method, and micromorphology changes of hippocampal CA1 were observed by light microscope at the end of the experiment.The general situations of rats such as body weights were recorded during the experiment.

RESULTS

Compared with Group NC, Group EM showed significantly decrease in body weight and hippocampal CA1 neurons of the group loosely arrayed and disarrayed and some neurons were shrinked, and even some neurons disappeared.The expressions of BDNF, TrkB and p-TrkB in group EM were increased significantly(<0.01).Compared with Group EM, body weight of Group ES was increased significantly, and the above mentioned injuries of neurons were improved significantly:the number of neurons and nissl bodies were significantly increased and the neurons arrayed regularly and its morphology was more complete.The expressions of BDNF, TrkB and p-TrkB in the group were increased significantly(<0.05 or <0.01).And there was no difference between Group ES and Group PC.

CONCLUSIONS

BDNF/TrkB neurotrophic signal pathway could be involved in the repair process of hippocampal nervous damage caused by incremental load exercise for fatigue rats.Spirulina supplement had a protective effect on the damaged nervous through increasing the expressions of BDNF, TrkB and p-TrkB.