Abstract: Objective To investigate the therapeutic mechanism of gastrodin injection for alleviating lung injury caused by focal cerebral ischemia in rats and the role of the NGF-TrkA pathway in mediating this effect.Methods Forty SD rats were equally randomized into normal group, sham-operated group, model group and gastrodin group, and in the latter two groups, rat models of focal cerebral ischemia were established by embolization of the right middle cerebral artery. After successful modeling, the rats were treated with intraperitoneal injection of gastrodin injection at the daily dose of 10 mg/kg for 14 days. After the treatment, the wet/dry weight ratio of the lung tissue was determined, the pathological changes in the lung tissue were observed using HE staining, and the levels of IL-10 and TNF- α in the arterial blood were detected with ELISA. The expressions of NF-κB p65 and TNF-α in the lung tissue were detected with Western blotting, and the expressions of NGF and TrkA were detected using immunohistochemical staining and Western blotting. Results Compared with the normal control and sham-operated groups, the rats in the model group showed obvious inflammatory lung injury, significantly increased wet/dry weight ratio of the lungs (P<0.01), increased TNF-α level in arterial blood (P<0.01), and significantly up-regulated protein expressions of NF- κB p65 (P<0.01), TNF- α (P<0.01), NGF (P<0.05) and TrkA(P<0.05) in the lung tissue. Treatment with gastrodin injection obviously alleviated lung inflammation, decreased the wet/dry weight ratio of the lungs (P<0.05), and significantly lowered TNF-α level (P<0.01) and increased IL-10 level in the arterial blood in the rat models (P<0.01); gastrodin injection also significantly decreased the protein expressions of NF- κB p65 and TNF- α (P<0.05) and up-regulated the expressions of NGF and TrkA in the lung tissue of the rats (P<0.05).Conclusion The NGF/TrkA pathway may participate in cerebral ischemia-induced inflammatory lung injury, which can be obviously alleviated by gastrodin through the activation of the anti-inflammatory pathway mediated by the NGF/TrkA pathway.

Key words: gastrodin; NGF/TrkA; cerebral ischemia; lung injury