Exploration of the Effect of Icariin on Nude Mice with Lung Cancer Bone Metastasis via the OPG/RANKL/RANK System

Epimedium is a traditional Chinese medicine that is most commonly prescribed by practitioners of Chinese medicine for the clinical treatment of malignant tumor bone metastasis. The main component of Epimedium is icariin (ICA). Studies have shown that ICA inhibits bone resorption of osteoclasts through the OPG/RANKL/RANK signaling pathway. Osteoclasts are the only cells in the body that have a bone-destroying capability. The OPG/RANKL/RANK system consists of cytokines that play major roles in osteoclast formation. Therefore, our study selected the OPG/RANKL/RANK system as the research target to investigate the effect of ICA on nude mice with lung cancer bone metastasis. We established the model of bone metastasis in nude mice, intervened the model with icariin and zoledronic acid, and detected the levels of OPG and RANKL by ELISA and western blot. The results showed that ICA had a significant inhibitory effect on bone metastases in nude mice. ICA achieved its antibone metastasis effect in nude mice with lung cancer via inhibiting RANKL expression and simultaneously increasing OPG expression. ICA not only alleviated osteolytic bone destruction caused by bone metastases, but it also reduced weight loss in tumor-bearing nude mice at the late stage of the experiment. The role of ICA in preventing bone metastasis of lung cancer merits further investigation.