Role of betaine in liver injury induced by the exposure to ionizing radiation

Oxidative stress, apoptosis, and fibrosis may play a major role in the development of radiation-induced liver damage. Betaine, a native compound widely present in beetroot, was reported to possess hepato-protective properties. The objective of this study was to investigate the influence of betaine on radiation-induced liver damage. Animals were exposed to 9 Gy applied in 3 doses of 3 Gy/wk. Betaine (400 mg/kg/d), was orally supplemented to rats after the first radiation dose, and daily during the irradiation period. Animals were sacrificed 1 day after the last dose of radiation. The results showed that irradiation has induced oxidative stress in the liver denoted by a significant elevation in malondialdehyde, protein carbonyl, and 8-hydroxy-2-deoxyguanosine with a significant reduction in catalase activity and glutathione (GSH) content. The activity of the detoxification enzyme cytochrome P450 (CYP450) increased while GSH transferase (GSH-T) decreased. The activity of the apoptotic marker caspase-3 increased concomitant with increased hyaluronic acid, hydroxyproline, laminin (LN), and collagen IV. These alterations were associated with a significant increase of gamma-glutamyl transferase, alkaline phosphatase and alanine and aspartate aminotransferase markers of liver dysfunction. Betaine treatment has significantly attenuated oxidative stress, decreased the activity of CYP450, enhanced GSH-T, reduced the activity of caspase-3, and the level of fibrotic markers concomitant with a significant improvement of liver function. In conclusion, betaine through its antioxidant activity and by enhancing liver detoxification and reducing apoptosis may alleviate the progression of liver fibrosis and exert a beneficial impact on radiation-induced liver damage.