Chaihu Longgu Muli Decoction relieving temporal lobe epilepsy in rats by inhibiting TLR4 signaling pathway through miR-146a-3p and miR-146a-5p

Objective

To explore the effect and mechanism of Chaihu Longgu Muli Decoction (柴胡龙骨牡蛎汤, CHLGMLD) in rats with temporal lobe epilepsy (TLE).

Methods

A total of 80 Sprague-Dawley (SD) male rats were randomized into control (CON), model (MOD), carbamazepine (CBZ, 0.1 g/kg), CHLGMLD low dose (CHLGMLD-L, 12.5 g/kg), and high dose (CHLGMLD-H, 25 g/kg) groups, with 16 rats in each group. TLE rat models were established in the four groups with the use of lithium-pilocarpine except for the CON group. After the successful establishment of TLE models, all drugs were administered through gavage, and distilled water was given to rats in the CON and MOD groups for four weeks. The frequency and duration of seizures before and after treatment were recorded for the evaluation of the alleviation degree. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression levels of miR-146a-3p and miR-146a-5p. The expression levels of toll-like receptor 4 (TLR4), interleukin-1 receptor-associated kinase 1 (IRAK1), tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6), TAK1-binding protein (TAB), nuclear factor-kappa B (NF-κB), and interleukin-1 beta (IL-1β) in hippocampus were tested by immunofluorescence assay. Correlation analysis between the above factors and expressions of miR-146a-3p and miR-146a-5p were performed separately.

Results

CHLGMLD decreased the frequency (P < 0.05) and duration (P < 0.01) of seizures in rats. CHLGMLD down-regulated the expression levels of miR-146a-5p and miR-146a-3p (P < 0.05), and inhibited the expression levels of TLR4, IRAK1, TRAF6, TAB, NF-κB, and IL-1β (P < 0.01). The correlation analysis revealed that the expression levels of TLR4, IRAK1, TRAF6, TAB, NF-κB, and IL-1β were positively correlated with the expression levels of miR-146a-3p and miR-146a-5p detected by qRT-PCR, respectively (P < 0.01).

Conclusion

CHLGMLD can inhibite the TLR4 signaling pathway by lowering the expression levels of miR-146a-3p and miR-146a-5p to alleviate hippocampal dentate gyrus inflammation in TLE rats, thus relieving seizures.