Synchrotron radiation(SR) X-ray has significant potential for medical applications. However, the mechanisms underlying the effects of SR X-ray on biological tissues remain unclear. Because increasing evidence has indicated critical roles of cluster of differentiation 38(CD38) in various cellular functions and cell survival, in this study we used rodent testes as a model to determine the effects of SR X-ray irradiation on the CD38 level of the testes. We found that SR X-ray irradiation led to a significant increase in the CD38 level of rodent testes one day after the irradiation. In contrast, the SR X-ray irradiation did not produce a significant increase in the CD38 level of the testes from the rats that were administered with the antioxidant N-acetyl cysteine, thus suggesting that oxidative stress plays a significant role in the SR X-ray irradiation-induced increase in the CD38 levels. Our study has also provided evidence suggesting that poly(ADP-ribose) polymerase(PARP) activity is not involved in the SR X-ray irradiation-produced effect on the CD38 levels. Collectively, this study has provided first in vivo evidence indicating that CD38 levels can be increased by ionizing radiation, in which oxidative stress plays an important role. Because oxidative stress occurs in ionizing radiation as well as such diseases as cerebral ischemia and Parkinson's disease, oxidative stress may produce pathological effects by inducing increased CD38 levels.
