Inhibitory effect and the mechanism of Astragalus polysaccharide combined with cisplatin on growth of inplanted Lewis lung carcinoma in mice

Abstract Objective To observe the effect of Astragalus polysaccharides (APS) combined with cisplatin (DDP) on the expressions of cytochrome C (CytC) and high temperature required serine protease A2 (Omi/HtrA2) in the mice with Lewis lung carcinoma (LLC) transplantated tumors. Methods Ninty C57BL/6J mice were randomly divided into normal control group, model group, and (50, 100, 200) μg/mL APS groups, 6 mg/kg DDP group, 3 mg/kg DDP combined with (50, 100, 200) μg/mL APS groups. Each group included 10 mice. Except the mice in the normal group, the rest mice were inoculated subcutaneously with LLC cells (1×10(7) mL) at the right fore axillary fossa to establish tumor-bearing mouse models. In the second day of building models, the mice in the treatment group were given intraperitoneal injection of 0.3 mL of the drug. DDP was given once a week, and the other drugs once a day. The mice in the normal group and the model group were administrated the same amount of saline injection for continuous 20 days. All mice were killed at the 21st day. The pathological changes of tumor tissues were observed by HE staining. The expressions and location of CytC and Omi/HtrA2 proteins in the transplanted tumor tissues were detected by immunohistochemical staining and image analysis. Results The mass of tumor decreased in the mice of (100, 200) μg/mL APS group and 3 mg/kg DDP combined with (100, 200) μg/mL APS group. Compared with the model group, the necrosis of tumor tissues in 200 μg/mL APS combined with 3 mg/kg DDP group was the most obvious. The expressions of CytC and Omi/HtrA2 increased in the treatment groups, and the increase was the most remarkable in 200 μg/mL APS combined with 3 mg/kg DDP group. Conclusion APS and APS combined with DDP can restrain the growth of Lewis Lung cancer in C57BL/6J mice, which may be related to the increased expressions of CytC and Omi/HtrA2.