[Effects and activity of paeoniflorin in zebrafish model of epilepsy induced by pentylenetetrazol].

This study aimed to investigate the neuroprotective effects of paeoniflorin in a pentylenetetrazol(PTZ)-induced zebrafish model of epilepsy. Zebrafish at four days post-fertilization with normal development were randomly divided into a control group, a model group, a positive control group(sodium valproate), and paeoniflorin treatment groups(200, 400, and 800 μmol·L~(-1)). Behavioral analysis was performed to evaluate changes in locomotor activity. Fluorescence microscopy was employed to evaluate neuronal discharge in the brain, cellular apoptosis, and the accumulation of neutrophils and macrophages. The levels of reactive oxygen species(ROS) and malondialdehyde(MDA) in the brain were measured to assess antioxidant capacity. Quantitative real-time polymerase chain reaction(RT-qPCR) was used to detect the mRNA expression levels of epilepsy-related genes(c-fos, brain-derived neurotrophic factor [BDNF], and galanin [GALN]) and inflammation-related genes(interleukin [IL]-1β, IL-6, and tumor necrosis factor-α [TNF-α]). Furthermore, the TLR4 receptor agonist lipopolysaccharide(LPS) was used for intervention. Behavioral analysis and RT-qPCR were conducted to detect the mRNA expression levels of Toll-like receptor 4(TLR4), myeloid differentiation factor 88(MyD88), nuclear factor-κB(NF-κB), and IL-1β, in order to verify the role of the related signaling pathway. The results demonstrated that, compared with the model group, paeoniflorin improved PTZ-induced epileptic behaviors, reduced the total swimming distance and velocity of zebrafish, and significantly downregulated the mRNA expression levels of epilepsy-related genes c-fos, BDNF, and GALN. Meanwhile, paeoniflorin significantly inhibited PTZ-induced abnormal neuronal discharge in the brain, suppressed cellular apoptosis, and reduced ROS levels and MDA content. In addition, paeoniflorin significantly attenuated the PTZ-induced accumulation of macrophages and neutrophils in the brain and downregulated the expression of inflammatory genes IL-1β, IL-6, and TNF-α. Further findings demonstrated that LPS intervention significantly attenuated the ameliorative effects of paeoniflorin on PTZ-induced epileptiform behaviors in zebrafish. RT-qPCR results showed that LPS treatment markedly reversed the inhibitory effects of paeoniflorin on the mRNA expression levels of TLR4, MyD88, NF-κB, and IL-1β in PTZ-induced zebrafish. In conclusion, this study indicates that paeoniflorin may exert its neuroprotective effects in a PTZ-induced zebrafish epilepsy model primarily by suppressing the activity of the TLR4/NF-κB signaling pathway, thereby reducing oxidative stress and inflammatory responses in the brain, suppressing neuronal apoptosis, and alleviating abnormal neuronal discharge.