Tanreqing Injection Attenuates Lipopolysaccharide-Induced Airway Inflammation through MAPK/NF-kappa B Signaling Pathways in Rats Model

Background. Tanreqing injection (TRQ) is a commonly used herbal patent medicine for treating inflammatory airway diseases in view of its outstanding anti-inflammatory properties. In this study, we explored the signaling pathways involved in contributions of TRQ to LPS-induced airway inflammation in rats. Methods/Design. Adult male Sprague Dawley (SD) rats randomly divided into different groups received intratracheal instillation of LPS and/or intraperitoneal injection of TRQ. Bronchoalveolar Lavage Fluid (BALF) and lung samples were collected at 24 h, 48 h, and 96 h after TRQ administration. Protein and mRNA levels of tumor necrosis factor-(TNF-) alpha, Interleukin-(IL-) 1 beta, IL-6, and IL-8 in BALF and lung homogenate were observed by ELISA and real-time PCR, respectively. Lung sections were stained for p38 MAPK and NF-kappa B detection by immunohistochemistry. Phospho-p38 MAPK, phosphor-extracellular signal-regulated kinases ERK1/2, phospho-SAPK/JNK, phospho-NF-kappa B p65, phospho-IKK alpha/beta, and phospho-I kappa B-alpha were measured by western blot analysis. Results. The results showed that TRQ significantly counteracted LPS-stimulated release of TNF-alpha, IL-1 beta, IL-6, and IL-8, attenuated cells influx in BALF, mitigated mucus hypersecretion, suppressed phosphorylation of NF-kappa Bp65, I kappa B-alpha,IKK alpha/beta, ERK1/2, JNK, and p38 MAPK, and inhibited p38 MAPK and NF-kappa B p65 expression in rat lungs. Conclusions. Results of the current research indicate that TRQ possesses potent exhibitory effects in LPS-induced airway inflammation by, at least partially, suppressing the MAPKs and NF-kappa B signaling pathways, in a general dose-dependent manner.