Study On Protective Effect Of Curcumin On¹²C⁶⁺ Ion Beams Induced Irradiation Damage In Mice

Curcumin (Cur) is one of the most effective active ingredient in turmeric. What’smore, Cur is recently proved to exert its effects partly radioprotection. To research thepossible protective effects and mechanisms of Cur, the healthy mice were exposure to12C6+ion beams. The investigation consist of Cur against the irradiation damage oftestis and brain in mice induced by12C6+ion beams.1. Protective effects of Cur against testicular damage induced by12C6+ion beamsin mice.Male Kun-ming mice were exposed to whole body uniformly irradiated with12C6+ion beams at4Gy after pretreated with Cur of different concentration. Thenhistological alterations were observed. Moreover, malonaldehyde (MDA) level,superoxide dismutase (SOD) activity and catalase (CAT) activity were also measuredat24hours after irradiation.The results showed that the middle dose pretreated with Cur have a good protectiveeffect in HE staining. And compared with irradiated group, MDA level decreasedsignificantly in the group of pretreatment with low dose Cur (p<0.05). On the contrary,SOD activity in the pretreated group with low dose Cur significantly increased(p<0.05). Similarly, CAT activity in the pretreated group with middle dose Cur significantly increased (p<0.05). All those results indicated Cur could activateantioxidant system of testis in mice against12C6+ion beams induced injury, and itplays an important beneficial role in protection against radiation damage. Themechanisms may attribute to its scavenging reactive oxidant species capability,improve the activity of antioxidant enzyme and protect lipid and protein.2. Protective effects of Cur against brain damage induced by12C6+ion beams inmice.The mice were exposed to whole body uniformly irradiated with12C6+ion beams at4Gy after pretreated with Cur. One month later, the cognitive ability of mice wasdetected by morris water maze (MWM). Malonaldehyde (MDA) level, superoxidedismutase (SOD) activity were measured after the MWM. At the same time, thechanges of nuclear erythroid2-related factor2(Nrf2) protein, heme oxygenase-1(HO-1), γ-glutamyl cysteine synthetase (γ-GCS), and NADP(H) quinineoxidoreductase1(NQO1) were detected and histopathologic changes were alsoobserved.The results showed4Gy heavy ion radiation-induced spatial strategy and memorydecline, augmentation of cerebral MDA, as well as the reduction of brain SOD activitylevels, were all consistently relieved by Cur. Furthermore, the cerebral cells Nrf2protein and three typically recognized Nrf2downstream genes, HO-1, γ-GCS, andNQO1were consistently up-regulated in curcumin pretreated mice. Our studyconfirmed the antagonistic roles of Cur to counteract radiation-induced cerebral injuryin vivo. On the one hand, Cur directly attenuates ROS production. On the other hand,Cur indirectly induces antioxidant enzymes via increasing the potent Nrf2, HO-1,γ-GCS, and NQO1activation capability, and enhances the ability to scavenging ROS.The above mechanisms might be valuable for the protective effects of Cur against12C6+ion beams radiation damage and provides a potential useful radioprotectiondietary component.