To investigate the thoracic irradiation induced abscopal effect on distal testes and the underlying inflammatory factors, the rats were irradiated on right thorax with fractionated doses. It was found the testes structures were damaged including disorder of spermatogenic cell arrangement and decrease of sperm number. Moreover, the expressions of caspase-3 and caspase-8 in testis tissue were enhanced, and the concentrations of TGF-beta and TNF-alpha in the rat serum were increased. When TM4 cells were treated with the conditioned medium (CS) collected from irradiated rat, the cellular ROS and apoptosis was significantly increased. When the CS was neutralized with anti-TGF-beta, its toxic effects were reduced. These results suggest that the thoracic irradiation-induced TGF-beta was involved in the above abscopal damage of testes, which reinforces the necessity of new prevention strategy development of radiotherapy in avoiding any abnormal genetic consequence. (C) 2019 Elsevier Inc. All rights reserved.