Radix Angelica Sinensis and Radix Hedysari Ultrafiltration Extract Protects against X‐Irradiation‐Induced Cardiac Fibrosis in Rats

Radiation‐induced myocardial fibrosis (RIMF) is the main pathological change associated with radiation‐induced heart toxicity after radiation therapy in patients with thoracic tumors. There is an antifibrosis effect of Radix Angelica Sinensis and Radix Hedysari (RAS‐RH) ultrafiltration extract from Danggui Buxue decoction (DBD) in X‐irradiation‐induced rat myocardial fibrosis, and this study aimed to investigate whether that effect correlated with apoptosis and oxidative stress damage in primary rat cardiac fibroblasts; further, the potential mechanisms were also explored. In this study, we first found that the RAS‐RH antifibrosis effect was associated with the upregulation of microRNA‐200a and the downregulation of TGF‐β1/smad3 and COL1α. In addition, we also found that the antifibrosis effect of RAS‐RH was related to the induction of apoptosis in primary rat cardiac fibroblasts and to the prevention of damage caused by reactive oxygen species (ROS). Interestingly, primary rat cardiac fibroblasts exposed to X‐ray radiation underwent apoptosis less frequently in the absence of RAS‐RH. Therefore, RAS‐RH has the ability to protect against fibrosis, which could be occurring through the induction of apoptosis and the resistance to oxidative stress in rats with X‐irradiation‐induced myocardial fibrosis; thus, in a model of RIMF, RAS‐RH acts against X‐irradiation‐induced cardiac toxicity.