Radioprotective effects of N-acetylcysteine on rats' brainstem following megavoltage X-irradiations.

Purpose: This study aimed to determine the radioprotective effect of N-acetylcysteine (NAC) on the radiation-induced oxidative stress (OS) in the rats' brainstem.

Materials And Methods: Eighty rats in four identical groups, including vehicle control (VC), irradiation alone (RAD), irradiation with 1 g/kg of NAC treatment (RAN), and NAC treatment without radiation (NAC) were used. Whole-brain irradiation was performed with a single dose of 25 Gy. The rats received the treatments via intraperitoneal (IP) injection 1 h before the irradiation process. Nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC), and glutathione peroxidase (GPx) were measured in the rats' brainstem and compared between the groups. Furthermore, the pathological study was performed to assess tissue damage after 24 h, 72 h, and 5 days of irradiation.

Results: The levels of NO and MDA in the brainstem tissue for the RAD group were 60.37 ± 3.35 μmol/L and 45.10 ± 2.48 μM, respectively, which were higher than those of VC group (NO: 30.41 ± 1.83 μmol/L; MDA: 31.02 ± 1.71 μM). The level of SOD, CAT, TAC, and GPx declined in the RAD compared to the VC group. Pre-treatment with NAC decreased the level of NO and MDA and also enhanced the antioxidant activities. The greatest pathological changes in the rats' brainstems were seen in RAD animals compared to the VC group at 24 h, 72 h, and 5 days. Furthermore, the pathological changes were not observed in the NAC group in all the assessed times.

Conclusion: Based on the results, NAC can decrease the irradiation-induced oxidative stress and pathology damages in the rats' brainstem. It can be concluded that NAC can be an appropriate radioprotection candidate for the human brainstem.