Effect of Yinxing Mihuan Oral Solutionon P2RX7/NLRP3 Signaling Pathway in Depression Model Rats Induced by Isolation Combined with Chronic Unpredictable Mild Stress / 中国实验方剂学杂志

ABSTRACT

Objective:To explore the antidepressant mechanism of Yinxing Mihuan oral solution （YMO） by investigating its effect on depression model rats. Method:The depression rats were induced by isolation combined with chronic unpredictable mild stress （CUMS） and then randomly divided into model group， fluoxetine group （10 mg·kg^-1） and high-dose （618 mg·kg^-1） and low-dose （309 mg·kg^-1） YMO groups. A blank control group was also set up and ten rats were included in each group. Modeling lasted for 21 consecutive days， and rats were administered the 8th day after stimulation at a dose of 10 mL·kg^-1 for 14 days， except those in the blank control and model groups which were given distilled water. Afterward， the sucrose preference test， open field test， tail suspension test were carried out. The pathological changes of hippocampus in depression rats were observed after hematoxylin-eosin （HE） staining. The content of interleukin-1<italic>β </italic>（IL-1<italic>β</italic>）， interleukin-6 （IL-6） and tumor necrosis factor-<italic>α </italic>（TNF-<italic>α</italic>） in the hippocampus of rats in each group and the expression of NOD-like receptor 3 （NLRP3） and other proteins in its related activation signaling pathways were detected with multi-factor detection （Luminex） and Western blot. Result:After 14 days of continuous administration， compared with the blank control group， the model group witnessed significantly reduced sugar water consumption rate and the times of rearing and significantly prolonged cumulative time of immobility during tail suspension （<italic>P</italic><0.05， <italic>P</italic><0.01）. Compared with the model group， the fluoxetine group and the high-dose YMO group saw increases in the times of rearing， times of crossing and sugar water consumption rate and a significant decrease in the cumulative time of immobility during tail suspension （<italic>P</italic><0.05， <italic>P</italic><0.01）. The results of HE staining showed that the neurons in the hippocampus of rats in the high-dose YMO group were arranged in order and slightly loosened， without obvious microglia infiltration observed. The levels of IL-1<italic>β</italic>， IL-6 and TNF-<italic>α</italic> in the hippocampus of the model group increased significantly as compared with the blank control group （<italic>P</italic><0.05， <italic>P</italic><0.01）， and their content in the high-dose YMO group was significantly lowered in the comparison with the model group （<italic>P</italic><0.05， <italic>P</italic><0.01）. Molecular biology experiments demonstrated that compared with the results of blank group， the expression of purinergic receptor P2X7 （P2RX7）， NLRP3， apoptosis-associated speck-like protein （ASC）， Caspase-1 and IL-1<italic>β</italic> remarkably increased in the model group （<italic>P</italic><0.05， <italic>P</italic><0.01）. Additionally， the expression of P2RX7， NLRP3， ASC， Caspase-1 and IL-1<italic>β </italic>was significantly inhibited in the fluoxetine group and the high-dose YMO group compared with the model group （<italic>P</italic><0.05， <italic>P</italic><0.01）. Conclusion:YMO can improve the depression-like behaviors of rats induced by isolation combined with CUMS， and its mechanism of action is related to the regulation of the P2RX7/NLRP3 signaling pathway.