Al-Saleh Farah, Khashab Farah, Fadel Fatemah, Al-Kandari Nora, Al-Maghrebi May
Department of Biochemistry, Faculty of Medicine, Kuwait University, Jabriyah, Kuwait.
Saudi J Biol Sci. 2020 Aug;27(8):2174-2184. doi: 10.1016/j.sjbs.2020.04.024. Epub 2020 Apr 21.
Testicular torsion and detorsion (TTD) is a serious urological condition affecting young males that is underlined by an ischemia reperfusion injury (tIRI) to the testis as the pathophysiological mechanism. During tIRI, uncontrolled production of oxygen reactive species (ROS) causes DNA damage leading to germ cell apoptosis (GCA). The aim of the study is to explore whether inhibition of NADPH oxidase (NOX), a major source of intracellular ROS, will prevent tIRI-induced GCA and its association with endoplasmic reticulum (ER) stress. Sprague-Dawley rats (n = 36) were divided into three groups: sham, tIRI only and tIRI treated with apocynin (a NOX inhibitor). Rats undergoing tIRI endured an ischemic injury for 1 h followed by 4 h of reperfusion. Spermatogenic damage was evaluated histologically, while cellular damages were assessed using real time PCR, immunofluorescence staining, Western blot and biochemical assays. Disrupted spermatogenesis was associated with increased lipid and protein peroxidation and decreased antioxidant activity of the enzyme superoxide dismutase (SOD) as a result of tIRI. In addition, increased DNA double strand breaks and formation of 8-OHdG adducts associated with increased phosphorylation of the DNA damage response (DDR) protein H2AX. The ASK1/JNK apoptosis signaling pathway was also activated in response to tIRI. Finally, increased immuno-expression of the unfolded protein response (UPR) downstream targets: GRP78, eIF2-α1, CHOP and caspase 12 supported the presence of ER stress. Inhibition of NOX by apocynin protected against tIRI-induced GCA and ER stress. In conclusion, NOX inhibition minimized tIRI-induced intracellular oxidative damages leading to GCA and ER stress.
睾丸扭转与复位（TTD）是一种严重的泌尿系统疾病，影响年轻男性，其病理生理机制为睾丸缺血再灌注损伤（tIRI）。在tIRI过程中，氧自由基（ROS）的失控产生会导致DNA损伤，进而引发生殖细胞凋亡（GCA）。本研究的目的是探讨抑制细胞内ROS的主要来源——NADPH氧化酶（NOX）是否能预防tIRI诱导的GCA及其与内质网（ER）应激的关联。将36只Sprague-Dawley大鼠分为三组：假手术组、仅tIRI组和用夹竹桃麻素（一种NOX抑制剂）治疗的tIRI组。经历tIRI的大鼠先经受1小时的缺血损伤，然后再灌注4小时。通过组织学评估生精损伤，同时使用实时PCR、免疫荧光染色、蛋白质免疫印迹和生化分析来评估细胞损伤。由于tIRI，生精过程紊乱与脂质和蛋白质过氧化增加以及超氧化物歧化酶（SOD）的抗氧化活性降低有关。此外，DNA双链断裂增加以及8-OHdG加合物的形成与DNA损伤反应（DDR）蛋白H2AX的磷酸化增加有关。ASK1/JNK凋亡信号通路也因tIRI而被激活。最后，未折叠蛋白反应（UPR）下游靶点GRP78、eIF2-α1、CHOP和半胱天冬酶12的免疫表达增加支持了ER应激的存在。夹竹桃麻素抑制NOX可预防tIRI诱导的GCA和ER应激。总之，抑制NOX可将tIRI诱导的细胞内氧化损伤降至最低，从而减少GCA和ER应激。
