Effect of Sinisan on NLRP3 Inflammasomes and Depression-like Behaviors in Depressed Rats / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo observe the effects of Sinisan on behaviors and NOD-like receptor protein 3 （NLRP3） inflammasomes of depressed rats induced by chronic unpredictable mild stress （CUMS） and further explore the anti-depressant mechanism of Sinisan. MethodFifty male rats were randomly divided into a normal group， a model group， an NLRP3 inhibitor （MCC950） group （10 mg·kg-1）， and low- （2.5 g·kg-1） and high-dose （5 g·kg-1） Sinisan groups， with 10 rats in each group. The depression model was induced by 42 d CUMS in rats except for those in the normal group. Drug intervention was performed on the 22nd day of modeling by gavage in the Sinisan groups and by intraperitoneal injection in the MCC950 group. Except for the MCC950 group， the remaining four groups received 10 mg·kg-1 physiological saline by intraperitoneal injection， while the rats in the model group， the normal group， and the MCC950 group were administered with 3 mL of physiological saline by gavage. Twenty-one days later， the sucrose preference test and open field test were performed. Western blot was used to detect the protein expression of NLRP3， apoptosis-associated speck-like protein containing a CARD （ASC）， cysteinyl aspartate-specific protease-1 （Caspase-1）， B-cell lymphoma-2 （Bcl-2）， Bcl-2 associated X protein （Bax）， ionized calcium-binding adapter molecule 1 （Iba1）， and CD68 in the hippocampus of rats in each group. Enzyme-linked immunosorbent assay （ELISA） was used to detect the levels of interleukin-1β （IL-1β） and interleukin-18 （IL-18） in the hippocampus of rats. Nissl staining and TUNEL were used to assess the pathological changes and apoptosis level in the hippocampal CA1 region of rats， respectively. ResultThe sucrose preference rate and consumption volume in the sucrose preference test， the total distance， the percentage of central movement distance， and the percentage of residence time in the open field test of rats in the model group were lower than those in the normal group （P<0.01）. Compared with the model group， the Sinisan groups and the MCC950 group showed improved depression-like behaviors， apoptosis level in the hippocampal CA1 region， and neuron loss to varying degrees. Sinisan could reduce the levels of IL-1β， IL-18， Bax， Iba1， and CD68 in the hippocampus （P<0.05， P<0.01）， increase the level of Bcl-2 （P<0.05， P<0.01）， and inhibit the protein expression of NLRP3， ASC， and Caspase-1 related to NLRP3 inflammasomes （P<0.05， P<0.01）. ConclusionSinisan can improve the depression-like behaviors and pathological damage of hippocampal neurons in CUMS-induced rats， and the mechanism may be related to the inflammatory response mediated by the NLRP3 inflammasome signaling pathway.