ObjectiveTo investigate the therapeutic effect of Lycopi Herba extract on chronic prostatitis （CNP） and explore the underlying action mechanism via the inflammasome NOD-like receptor protein 3 （NLRP3） pathway. MethodNormal human prostatic stromal cells， namely WPMY-1 were induced by lipopolysaccharide （LPS） of 5 mg·L^-1， and the effects of Lycopi Herba extract of 3.125， 6.25， 12.5， 25， 50， and 100 mg·L^-1 on interleukin-6 （IL-6） level released by LPS-induced WPMY-1 cells were detected by enzyme-linked immunosorbent assay （ELISA）. The half-maximal inhibitory concentration （IC₅₀） was calculated. The expression of key proteins in the NLRP3 pathway was detected by western blot after Lycopi Herba extract of 50， 75， and 100 mg·L^-1 was administered to WPMY-1 cells. The rat model of CNP was established by injecting carrageenan salt solution into the abdominal lobe of the prostate gland. Hematoxylin-eosin （HE） staining was used to observe the histopathological changes in the prostate gland in rats. The prostate organ index of rats was measured. The level of 5α-dihydrotestosterone （5α-DHT） in serum， as well as the levels of IL-6， tumor necrosis factor-α （TNF-α）， transforming growth factor-β₁ （TGF-β₁）， cyclooxygenase-2 （COX-2）， prostaglandin E₂ （PGE₂）， and inducible nitric oxide synthase （iNOS） in prostate tissue were detected by ELISA. The key protein expressions of COX-2， TGF-β₁， and NLRP3 pathway in prostate tissue were detected by Western blot. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to detect the expressions of COX-2， IL-1β， TGF-β₁， and TNF-α mRNA in prostate tissue. ResultCompared with the normal group， the level of IL-6 and the protein expression levels of NLRP3， ASC， Caspase-1， and IL-1β of WPMY-1 cells in the model group were increased （P<0.05， P<0.01）. Compared with the model group， Lycopi Herba extract could inhibit the levels of IL-6 （P<0.01） released by LPS-induced WPMY-1 cells， with IC₅₀ of 38.26 mg·L^-1. The protein expression levels of NLRP3， ASC， and IL-1β in the low-， medium-， and high-dose groups of Lycopi Herba extract were significantly down-regulated （P<0.05， P<0.01）. The expression levels of Caspase-1 protein in medium- and high-dose groups of Lycopi Herba extract were significantly down-regulated （P<0.05， P<0.01）. Compared with the sham operation group， the prostate organ index of rats in the model group was significantly increased （P<0.01）， a large number of inflammatory cells were infiltrated in the prostate tissue， and the histopathological score was significantly increased （P<0.05）； the levels of 5α-DHT in serum， the levels of TNF-α， PGE₂， IL-6， TGF-β₁， NOS₂/iNOS， and COX-2 in prostate tissue， and expression levels of COX-2， IL-1β， and TGF-β₁ were significantly increased （P<0.05， P<0.01）. The mRNA expression levels of COX-2， TGF-β₁， NLRP3， Caspase-1， ASC， and IL-1β in prostate tissue were significantly up-regulated （P<0.05， P<0.01）. Compared with model group， the low and high doses of Lycopi Herba extract could alleviate the pathological changes in prostate tissue induced by carrageenan， significantly reduce the level of 5α-DHT in serum， levels of TNF-α， PGE₂， TGF-β₁， and iNOS in prostate tissue （P<0.05， P<0.01）， and mRNA expression levels of COX-2， IL-1β， and TGF-β₁ （P<0.05， P<0.01）. The protein expression levels of COX-2， Caspase-1， ASC， and NLRP3 in prostate tissue were significantly down-regulated （P<0.05， P<0.01）. The prostate organ index of the low-dose group of Lycopi Herba extract was significantly decreased （P<0.01）. The level of COX-2 in prostate tissue of the high-dose group of Lycopi Herba extract was significantly decreased， and the protein expression levels of TGF-β₁ and IL-1β were significantly down-regulated （P<0.05）. ConclusionLycopi Herba extract has an obvious therapeutic effect on CNP and may reduce inflammation by inhibiting the activation of the inflammasome NLRP3 signaling pathway.