Effect of Shenwei Ningyu Pills on Immunoinflammatory Response Mediated by TLR4/MyD88 Signaling Pathway in Hippocampus of Rats Exposed to Chronic Restraint Stress / 中国实验方剂学杂志

ABSTRACT

Objective:To explore the effects of Shenwei Ningyu pills （SNP）， a new Chinese medicine for depression， on the immunoinflammatory response mediated by Toll-like receptor 4 （TLR4）/myeloid differentiation factor 88 （MyD88） signaling pathway in the hippocampus of rats exposed to chronic restraint stress （CRS）. Method:Forty-four male Sprague Dawley rats were randomly enrolled into a normal group， a model group， an escitalopram group， and an SNP group. Except for the rats in the normal group， all rats were exposed to CRS and isolated rearing for 21 days continuously. Rats in the escitalopram group and the SNP group were administered with escitalopram （30 mg·kg^-1） and SNP （18 mg·kg^-1） one hour prior to CRS， respectively. The changes in body weight， sucrose preference index， horizontal movement scores， and vertical movement scores were observed by body weight assessment， sucrose preference test， and open field test. The expression of hippocampal TLR4 and MyD88 was detected by Western blot. The content of serum interleukin-1<italic>β</italic> （IL-1<italic>β</italic>）， IL-10， and tumor necrosis factor-<italic>α</italic> （TNF-<italic>α</italic>） was detected by enzyme-linked immunosorbent assay （ELISA）. Result:The results of the behavioral assessment showed that there was no significant difference in the changes of behavioral baselines among the groups before intervention. However， significant differences were found among the groups following different interventions. The body weight， sugar preference index， horizontal movement score， and vertical movement score of rats in the model group decreased after CRS for 21 days as compared with those in the normal group （<italic>P</italic><0.01）. The above indicators in the SNP<italic> </italic>group and the escitalopram group were higher than those in the model group （<italic>P</italic><0.01）， which indicated that SNP<italic> </italic>exerted an obvious antidepressant effect. The results of Western blot and ELISA showed that compared with the normal group， the model group showed elevated levels of hippocampal TLR4 and MyD88 and serum IL-1<italic>β</italic> and TNF-<italic>α </italic>（<italic>P</italic>˂0.01） and dwindled serum IL-10 （<italic>P</italic>˂0.01）， while SNP<italic> </italic>and escitalopram reversed the conditions in the model group （<italic>P</italic>˂0.01） except for TNF-<italic>α</italic>. Conclusion:The present study indicated that the antidepressant effect of SNP was presumedly achieved by inhibiting the immunoinflammatory response mediated by the TLR4/Myd88 signaling pathway in CRS rats.