Protective effects of dihydromyricetin against radiation-induced injury to the hematopoietic system

To investigate the potential protective effects of dihydromyricetin (DHM), a primary bioactive compound derived from Ampelopsis grossedentata , against radiation-induced hematopoietic damage. The in virto antioxidant capacity of DHM was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2ʹ-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) assays. Survival rate and hematopoietic damage experiments were conducted on 130 mice. To assess the protective effects of DHM, a lethal dose of 7.5 Gy was delivered to 60 mice, and their 30-d survival rates were assessed and changes in their survival time were recorded. The mice were divided into 6 groups in survival analysis: DHM-only (200 mg/kg), IR, IR + low-dose DHM (50 mg/kg), IR + moderate-dose DHM (100 mg/kg), IR + high-dose DHM (200 mg/kg), and IR+amifostine (200 mg/kg). Subsequently, a hematopoietic injury model was established by subjecting 70 mice to whole-body irradiation (WBI) at a dose of 4 Gy. The mice were divided into 7 groups in the hematopoietic damage experiment: control, DHM-only (200 mg/kg), IR, IR + low-dose DHM (50 mg/kg), IR + moderate-dose DHM (100 mg/kg), IR + high-dose DHM (200 mg/kg), and IR+amifostine (200 mg/kg), with 10 mice in each group. The effects of DHM on body weights, blood routine indices, femoral nucleated cell counts, organ indices, and splenic nodules were analyzed. Using hematoxylin and eosin (H&E) staining, the effects of DHM on the spleen and bone marrow were examined. Furthermore, the antioxidant effects of DHM were evaluated by measuring biochemical markers including glutathione (GSH) and superoxide dismutase (SOD). DHM exhibited strong in vitro antioxidant activity (92.17% in the ABTS assay and 90.75% in the DPPH assay). It significantly improved both the survival time and rates of mice exposed to irradiation at a lethal dose (20% for the IR + low-dose DHM group, 40% for the IR + moderate-dose DHM group, and 50% for the IR + high-dose DHM group; P < 0.05). In the hematopoietic injury experiment, DHM greatly improved blood routine indices, including the white blood cell count and the lymphocyte percentage ( P < 0.01). Moreover, DHM considerably increased organ indices, the number of splenic nodules, and the nucleated cell count in the femoral bone marrow. H&E staining revealed that DHM significantly alleviated radiation-induced damage to the spleen and bone marrow. Additionally, DHM treatment greatly enhanced the hepatic GSH and SOD levels of the irradiated mice, reaching 219.01 and 199.53, respectively ( P < 0.05). Owing to its free radical scavenging potential, DHM can enhance the survival rates of mice exposed to radiation at a lethal dose and mitigate radiation-induced damage to the hematopoietic system. This study serves as a valuable reference for the application of traditional Chinese medicine in radioprotection.