Objective: To investigate the effect of Dachengqi Decoction (DCQD) on the key signaling molecules in lung and large intestine of mice with endotoxemia for exploring the exterior-interior relation between Fei and Dachang.
Methods: A total of 32 BALB/c mice were randomly and equally allocated into four groups: mice in Group C and D were made into endotoxemia model by intraperitoneal injection of 10 mg/kg lipopolysaccharide (LPS); while those in Group A and B were not modeled but given intraperitoneal injection of saline instead. Thirty min after then, saline to Group A and C, and DCQD to Group B and D were given by gastric infusion, and mice were sacrificed 6 h later. Their tissues of lung and large intestine were taken for observing pathological changes by inverted microscopy with HE staining; detecting expressions of tumor necrosis factor-alpha (TNF-alpha) by LiquiChip system; determining gene transcription and protein expression of toll-like receptor 4 (TLR4) using reverse transcription-polymerase chain reaction (RT-PCR) and Western blot, and the correlation of TNF-alpha and TLR4 levels in the lung and the large intestine tissue was analyzed. RESULTED: Compared with Group C, hemorrhage, pathologic toxemic features, including pulmonary edema and inflammatory cell infiltration as well as intestinal wall congestion and neutrophil infiltration, were significantly alleviated in Group D. Levels of TNF-alpha expression, TLR4 protein expression and gene transcription raised significantly in the modeled mice (P < 0.01), but comparison between the two modeled groups showed that the three parameters were lower in Group D than in Group C (P < 0. 01 or P < 0.05) respectively. Correlation analysis showed that the levels of TNF-alpha expression, TLR4 protein expression and gene transcription in pulmonary tissues were positively correlated with those in large intestinal tissues respectively (r = 0.973, P < 0.01, r = 0.906, P < 0.01, and r = 0.880, P < 0.01).
Conclusions: The effects of DCQD in alleviating pulmonary and large intestinal inflammation induced by endotoxemia might be correlated to its reduction on levels of TNF-alpha expression, TLR4 protein expression and gene transcription. Levels of the three parameters in the lung are correlated with the corresponding levels in the large intestine, which suggested the existence of exterior-interior relation between Fei and Dachang.