SBL-1 treatment before total body irradiation countered radiation induced oxidative stress, DNA damage and histological changes in jejunum of conditioned rats

Conditioned taste aversion (CTA) in experimental rats is considered to be parallel to behavioural changes (nausea and vomiting) in humans. There is a need to develop medical countermeasures which can counter the radiation induced nausea and vomiting. The standardized radioprotective preparation from leaves of Hippophae rhamnoides (Seabuckthorn, SBL-1) was also demonstrated to counter ⁶⁰Co γ-irradiation (2 Gy) induced CTA in experimental Sprague-Dawley rats. This study investigated the time dependent changes in oxidative stress, DNA damage (γH2AX assay) and histology of rats jejunum in SBL-1 (12 mg/kg b.w., i.p, ∼ 30 min) treated irradiated rats and compared it with the non SBL-1 treated irradiated rats. In comparison to untreated controls (DC), the irradiated animals showed significant increase (p<0.05) in levels of nitric oxide (NOx), lactate dehydrogenase (LDH) and γH2AX foci at 5 h and malondialdehyde (MDA) at 24 h; but decrease in total thiols (GSH), superoxide dismutase (SOD) and catalase (CAT); villi and crypt numbers per circumference as well as villi and crypt lengths at 5 h. The treatment with SBL-1 prior to irradiation countered the radiation induced increase in levels of MDA, NOx, LDH and γH2AX foci; decrease in GSH, SOD and CAT; villi and crypt numbers per circumference and villi and crypt lengths at 5 h. In irradiated group, on day 5 the levels of MDA, NOx, LDH, GSH, SOD and γH2AX foci were not different than UC but significant decrease persisted in levels of CAT, number of villi and crypts, and also villi length. In SBL-1 treated irradiated group, on day 5, there was significant reduction in MDA levels (p<0.05); increase of SOD levels to match the UC; the increase of villi and crypt numbers/circumference by 15-20%, in comparison to irradiated animals. The observations indicated that SBL-1 could counter the radiation induced oxidative stress, DNA damage and changes in tissue histology within 5 h. This may have been an important reason for amelioration of CTA reported earlier. More studies are in progress to understand the effects of radiation and SBL-1 observed at day 3 onwards. (author)