OBJECTIVE: To probe into the effects of berberine hydrochloride on the inflammatory signaling pathway of NOD-like receptor protein 3（ NLRP3） in rats with trigeminal neuralgia（ TN） and its protective effect on TN rats. METHODS: TN rat model was made by chronic constriction injury of infraorbital nerve model（ ION-CCI）method. The successfully modeled rats were randomly divided into the model group

low-dose group

medium-dose group and high-dose group of berberine hydrochloride（ 25 mg/kg

50 mg/kg

100 mg/kg）

with 15 rats in each group. Another 15 rats（ only the infraorbital nerve was isolated

without ligation） were taken as the sham operation group. The sham operation group and the model group were given the same amount of normal saline by gavage. The other groups received the corresponding dose of berberine hydrochloride by gavage with the volume of 10 ml/kg

once a day for 14 d. The mechanical pain threshold of facial innervation at different time points were measured by electronic pain tester. The levels of interleukin-1β（ IL-1β）

tumor necrosis factor-α（ TNF-α） in trigeminal ganglia of rats were detected by enzyme-linked immunosorbent assay（ ELISA）. The expression level of calcitonin gene-related peptide（ CGRP）

NLRP3

apoptosis-related speckle-like protein（ ASC） and caspase-1 mRNA in the trigeminal ganglion tissues of rats were detect by real-time fluorescent quantitative polymerase chain reaction（ qRT-PCR）. And the expression level of CGRP

NLRP3

ASC and caspase-1 protein in trigeminal ganglia were detected by Western Blot.RESULTS: Before modeling of 3 d and 1 d

there was no statistically significant difference in mechanical pain threshold among four groups（ P > 0. 05）. After modeling of 3 d and 1 d

compared with the sham operation group

the mechanical pain threshold in the model group decreased

with statistically significant difference（ P < 0. 05）

and there was no statistically significant difference between the model group and low-dose group

medium-dose group and highdose group of berberine hydrochloride（ P > 0. 05）. After modeling of 5 to 14 d

compared with the sham operation group

the mechanical pain threshold in the model group decreased

with statistically significant difference（ P <0. 05）; compared with the model group

the mechanical pain threshold of low-dose group

medium-dose group and high-dose group of berberine hydrochloride increased in turn with dose-dependent（ P < 0. 05）. On the 15 th d after surgery

compared with the sham operation group

the level of IL-1β

TNF-α and the expression level of mRNA and protein in CGRP

NLRP3

ASC and caspase-1 in trigeminal ganglion tissue of the rats in the model group increased

with statistically significant difference（ P < 0. 05）; compared with the model group

the level of IL-1β

TNF-α and the mRNA and protein expression level of CGRP

NLRP3

ASC and caspase-1 in the trigeminal ganglion tissue of the rats in the low-dose group

medium-dose group and high-dose group of berberine hydrochloride decreased in turn with dose-dependent（ P < 0. 05）. CONCLUSIONS: Berberine hydrochloride may reduce the release of inflammatory factors by down-regulating the signal pathway of NLRP3 inflammatory corpuscle

decrease the expression level of CGRP in trigeminal ganglion tissues

and increase the mechanical pain sensitivity threshold of the neurofacial sensory area

so as to reduce the injury of TN on rats.