Anti-inflammatory effect of Qingzaojiufei decoction on lung injury induced by SiO₂ in rats

Objective To explore the anti-inflammatory effect of Qingzaojiufei decoction (QD)on lung tissue damage induced by silicon dioxide(SiO₂)dust in rats.

Methods Totally 60 Wistar male rats were randomly divided into 6 groups, namely, negative control group(normal saline + normal saline), QD control groupnormal saline + QD(15 g/kg crude herb drugs), SiO₂ treated groupsSiO₂ treatment + saline and 3 QD intervention dose level(3.75, 7.5 and 15 g/kg crude herb drugs)groups, with 10 rats in each group. Rats were intratracheally given 1 mL of SiO₂ suspension(50 mg/mL), or 1 mL normal saline(as control)to establish an animal model of lung injury. Then the rats were intragastrically administrated with QD or normal saline once a day, 24 h after the modeling, for 28 consecutive days. After 28 days, the rats were sacrificed, and the lung tissues were harvested. Then HE staining and Masson staining were performed, the content of hydroxyproline (HYP) was determined by alkaline hydrolysis method, and the cytokine levels of TGF-β1, TNF-α, IL-1β, IL-10 and IFN-γ were in rat lung tissues were determined by ELISA.

Results Histopathological examination results showed that the damage of rat lung tissue in the three QD intervention groups was significantly alleviated. Compared with the SiO₂ model group, the lung wet weight and lung coefficient, the HYP content and the levels of TGF-β1, TNF-α and IL-1β in the lung tissue of the rats in QD intervention groups were significantly reduced (P < 0.05), and the levels of IL-10 and IFN-γ increased in different degrees (P < 0.05), with dose-response relationship.

Conclusions QD may reduce the damage of SiO₂ to the lung tissue of rats by inhibiting the proinflammatory factors TGF-β1, TNF-α, IL-1β and promoting the release of anti-inflammatory factors IL-10 and IFN-γ.