This study aimed to evaluate the histopathological and ultrastructural changes in sciatic nerve barriers after exposure to different doses of nicotine. Twenty-seven adult male rats were divided into 2 groups; group I served as control (n = 9) and group II that received nicotine (n = 18) was subdivided into two equal subgroups; group IIa and group IIb that were injected subcutaneously daily for one month with nicotine at a dose of 3 mg/kg and 6 mg/kg body weight, respectively. Specimens of sciatic nerve were processed for light and electron microscopy. Immunohistochemical expression of ZO-1 and vascular endothelium growth factor (VEGF) were investigated. Abundance of mRNA for VEGF was determined via qRT-PCR. Total antioxidant capacity (TAC), malondialdehyde (MDA), alanine transaminase (ALT) and aspartate transaminase (AST) were measured. Group IIb showed increased perineural fibrosis and myelin abnormalities. ZO-1 expression was significantly decreased. Schwann cells showed features of apoptosis and blood capillaries showed disrupted lining. High statistical difference in the level of mRNA expression of VEGF between group IIb and group I was found. There was decreased level of TAC and increased MDA, ALT and AST. A dose-dependent nicotine-induced oxidative stress on the sciatic nerve occurred via disruption of nerve barriers, altered VEGF and ZO-1 levels.

中文翻译：

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尼古丁诱导的氧化应激通过调节ZO-1和VEGF表达改变大鼠坐骨神经屏障。

这项研究旨在评估不同剂量尼古丁暴露后坐骨神经屏障的组织病理学和超微结构变化。将二十七只成年雄性大鼠分为两组。第一组作为对照组（n = 9），第二组接受烟碱（n = 18）分为两个相等的亚组。IIa组和IIb组每天分别皮下注射尼古丁，剂量分别为3 mg / kg和6 mg / kg体重。坐骨神经标本进行了光学和电子显微镜检查。研究了ZO-1和血管内皮生长因子（VEGF）的免疫组织化学表达。通过qRT-PCR确定VEGF的mRNA丰度。测量总抗氧化剂能力（TAC），丙二醛（MDA），丙氨酸转氨酶（ALT）和天冬氨酸转氨酶（AST）。IIb组显示神经周围纤维化和髓鞘异常增加。ZO-1表达明显降低。雪旺氏细胞表现出凋亡特征，毛细血管表现出内膜破坏。发现IIb组和I组之间VEGF mRNA表达水平有高度统计学差异。TAC水平降低，MDA，ALT和AST升高。剂量依赖性烟碱诱导的坐骨神经氧化应激是通过破坏神经屏障，改变VEGF和ZO-1水平而发生的。TAC水平降低，MDA，ALT和AST升高。剂量依赖性烟碱诱导的坐骨神经氧化应激是通过破坏神经屏障，改变VEGF和ZO-1水平而发生的。TAC水平降低，MDA，ALT和AST升高。剂量依赖性烟碱诱导的坐骨神经氧化应激是通过破坏神经屏障，改变VEGF和ZO-1水平而发生的。