BACKGROUND Pseudorabies virus (PRV) infection induces apoptosis in swine cells both in vitro and in vivo; however, the mechanism associated with host-cell signaling has not been studied. This study investigated the role of free radicals caused by cellular oxidative stress after viral infection and examined whether the DNA damage response plays an important role in PRV-induced apoptosis. METHODS Several apoptosis assays and western blotting confirmed PRV-induced apoptosis. PRV-mediated oxidative stress was evaluated by reactive oxygen species (ROS) assay. RESULTS Our results showed that PRV caused apoptosis in a porcine kidney cell line, PK15, and induced expressions of proapoptotic Bcl family proteins in a dose- and time-dependent manner. Expressions of specific DNA damage sensors and phosphorylation of histone H2AX were also significantly increased, which subsequently activated the expressions of checkpoint kinase 1/2 and proapoptotic p53. Caffeine, a known DNA damage inhibitor, was found to inhibit caspase-3 activation and protect cells from PRV-induced apoptosis. Additionally, the antioxidant N-acetyl-L-cysteine was shown to prevent the production of cellular ROS, protecting DNA from cleavage. CONCLUSIONS Our results confirmed that oxidative stress and free radicals arising from PRV infection cause DNA damage, which consequently triggers apoptosis.

中文翻译：

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伪狂犬病病毒通过氧化应激和随后的DNA损伤信号诱导细胞凋亡。

背景伪狂犬病病毒（PRV）感染可在体内和体外诱导猪细胞凋亡。然而，尚未研究与宿主细胞信号传导相关的机制。这项研究调查了病毒感染后细胞氧化应激引起的自由基的作用，并研究了DNA损伤反应是否在PRV诱导的细胞凋亡中起重要作用。方法几种凋亡测定和Western blotting证实PRV诱导的凋亡。PRV介导的氧化应激通过活性氧（ROS）分析进行评估。结果我们的结果表明，PRV引起猪肾细胞系PK15凋亡，并以剂量​​和时间依赖性方式诱导凋亡的Bcl家族蛋白的表达。特异性DNA损伤传感器的表达和组蛋白H2AX的磷酸化也显着增加，随后激活了检查点激酶1/2和促凋亡p53的表达。咖啡因是一种已知的DNA损伤抑制剂，被发现可以抑制caspase-3活化并保护细胞免受PRV诱导的细胞凋亡。此外，抗氧化剂N-乙酰基-L-半胱氨酸被证明可以防止细胞内ROS的产生，从而保护DNA免受切割。结论我们的结果证实了PRV感染引起的氧化应激和自由基引起DNA损伤，从而引发细胞凋亡。此外，抗氧化剂N-乙酰基-L-半胱氨酸被证明可以防止细胞内ROS的产生，从而保护DNA免受切割。结论我们的结果证实了PRV感染引起的氧化应激和自由基引起DNA损伤，从而引发细胞凋亡。此外，抗氧化剂N-乙酰基-L-半胱氨酸被证明可以防止细胞内ROS的产生，从而保护DNA免受切割。结论我们的结果证实了PRV感染引起的氧化应激和自由基引起DNA损伤，从而引发细胞凋亡。