Establishment of mouse alveolar macrophage extraction standard and its application in the evaluation of efficacy in lung metastasis of colorectal cancer

Objective: Alveolar macrophages (AMs) are involved in the development and progression of a variety of lung diseases. It is of great significance to explore the pathogenesis of diseases and evaluate the efficacy of drugs. However, there is no standard process for extracting primary AM. Nitidine chloride (NC) is an alkaloid extracted from Zanthoxylum nitidum ( Roxb .) DC ., which has an anti-tumour pharmacological effect. However, there is no evidence that NC has a direct effect on colorectal cancer cell lung metastasis. The purpose of this study was to establish a standard for the extraction of primary AM from mice and to investigate the pharmacodynamics of NC in mice with lung metastases to colorectal cancer. Methods: The standard for the extraction of mouse primary AM by lavage was established. Western blot and polymerase chain reaction were used to detect the regulatory mechanism of NC in the treatment of lung metastasis in mice by macrophage phenotype and glycolysis level. Results: The results showed that sufficient quantity and quality of primary AM could be obtained by optimizing extraction steps, and AM obtained by this method could accurately reflect disease progression. At the same time, NC can effectively reduce colorectal cancer lung metastasis in mice. From the mechanism, NC can inhibit the expression of M2 macrophage markers and the levels of mRNA and proteins of the glycolysis-limiting enzyme. Conclusions: Our results show that primary AM that accurately reflects disease and assesses pharmacological effects can be obtained using our established criteria. The inhibitory effect of NC on colorectal cancer lung metastasis may be attributed to its regulation of macrophage phenotype and glycolysis.