Total flavonoids in Scutellaria barbata prevents NLRP3 inflammasome expression in tumor cells by affecting autologous pathway / 中国中药杂志

ABSTRACT

This paper was aimed to investigate the relationship between autophagy and NLRP3 inflammasome activation by studying the effect oftotal flavonoids in Scutellaria barbata (TF-SB) on autophagy in tumor cells and NLRP3 inflammasome, and to provide experimental evidence for further study of the anti-tumor mechanism of TF-SB. Mielanoma models were established by inoculating B16-F1 cell line to mice, and then were randomly divided into 5 groups (n=10 in each group) model control, positive control control(Rap, 1.5 mg•kg⁻¹), and TF-SB low, middle and high groups (50, 100 and 200 mg•kg⁻¹). Meanwhile, healthy C57BL/6J mice were used as normal control group (n=10). The drugs were given once daily for 2 weeks consecutively. Thirty minutes after last treatment, the determinations at endpoint were performed; pathological changes of tumor tissue were evaluated by using HE staining; protein expressions of LC3-II/LC3-I or NLRP3inflammasome/caspase-1/IL-1β and IL-18 in tumor tissues were detected by using Western-blot; and serum levels of IL-1β and IL-18 were detected by using Elisa kit. The results showed that the tumor cells in model group showed obvious atypia and malignant proliferation; the invasion of tumor tissue was significantly reduced, the tumor necrosis area was significantly increased, and the inflammatory reaction was significantly alleviated in positive control group and various TF-SB groups. As compared with model control group, LC3-II/LC3-I was significantly increased, while NLRP3/caspase-1/IL-1βand IL-18 protein expressions were significantly decreased in positive control group and TF-SB groups. Serum IL-1β and IL-18 levels in model control group were found higher than those in control group (P<0.001), but they were significantly lowered in positive control group and TF-SB groups (P<0.05, P<0.01 or P<0.001). Taken together, total flavonoids in S. barbata could effectively alter the tumor growth micro-environment by inhibiting the expression of NLRP3 inflammasome, and its anti-tumor effect may be associated with the induction of tumor cell autophagy.