Ochratoxin A cytotoxicity on Madin–Darby canine kidney cells in the presence of alpha‐tocopherol: Effects on cell viability and tight junctions

Ochratoxin A (OTA) is a potent nephrotoxic fungi metabolite that affects animal and human health. At the cellular level, OTA is able to alter functions and viability by several mechanisms of action. Several strategies to counteract its toxicity have been studied. We investigated the role of α‐tocopherol in counteracting OTA oxidative damage in Madin–Darby canine kidney (MDCK) cells by pre‐incubating the cells for 3 hr with the antioxidant (1 nm , 10 μm ) and then adding OTA (0–1.2 μg/ml) for the following 24 hr. Cell viability, lactate dehydrogenase (LDH) release, TUNEL staining and occludin and Zo1 localization by immunofluorescence were determined. Here, 1 nm α‐tocopherol was shown to significantly reduce (p < .05) the cytotoxicity, LDH release and apoptotic rate induced by OTA. The presence of the antioxidant at the same concentration maintained the localization of occludin and Zo1 in the rim of the MDCK cells after the 24‐hr OTA exposure. These results indicate that a low concentration of α‐tocopherol could block OTA toxicity, supporting its defensive role in the cellular membrane.     

Effect of local scrotal heating on the expression of tight junction‐associated molecule Occludin in boar testes

The aim of this study was to determine whether local scrotal heating (42°C, for 1 hr) had an effect on the expression of tight junction (TJ)‐associated molecule Occludin in boar testes. Adult boars (Landrace, n = 6) were used and randomly divided into two groups (n = 3 each). Three boars were given local scrotal exposure to 42°C for approximately 1 h with a home‐made electric blanket of controlled temperature as local scrotal heating group, the other three boars received no heat treatment and were left at standard room temperature as control group. After 6 hr, all boars were castrated and the testes were harvested. qRT‐PCR, Western blotting and immunohistochemistry were used to explore the expression and localization of Occludin. qRT‐PCR and Western blotting showed that the protein and mRNA levels of Occludin significantly decreased in local scrotal heating group as compared to the control. Furthermore, immunoreactivity staining of Occludin was localized at the sites of the blood–testis barrier (BTB) and formed an almost consecutive and strong immunoreactivity strand in the control, while Occludin was limited to Sertoli cells (SCs) and no obvious immunoreactivity strand was present in local scrotal heating group. These data indicated that local scrotal heating decreased the expression of TJ‐associated molecule Occludin, which may be involved in heat‐induced spermatogenesis damage.     

益生菌调控肠道闭锁蛋白表达的机制

紧密连接是肠上皮细胞间的主要连接方式,参与维持上皮细胞极性与调节肠屏障的通透性。闭锁蛋白(OCLN)是紧密连接相关蛋白中最具代表性的蛋白之一,是形成紧密连接的基础结构。OCLN的功能主要包括栅栏功能和细胞旁屏障功能,研究发现其表达量降低时可引起肠黏膜屏障功能受损,后者是多种消化道疾病发生发展的一个重要过程。益生菌被认为是抗生素的重要替代物之一,其作用于宿主可产生多种有益作用。大量研究表明给予患者或者为疾病模型动物提供益生菌可有效改善肠黏膜屏障功能。本文就益生菌对肠道OCLN蛋白表达调控机制的研究作一综述,以期为OCLN相关研究和疾病的治疗策略提供理论参考。     

补肾祛痰活血汤对缺血再灌注损伤大鼠Occludin、ZO-1蛋白的调节作用

目的 观察补肾祛痰活血汤对预处理脑缺血再灌注损伤的大鼠脑组织水肿、血脑屏障通透性及损伤区咬合蛋白（Occludin）、闭锁小带蛋白（zonula occludens-1,ZO-1）的影响。方法 SD成年雄性大鼠50只,按随机数字表法分为正常组、模型组、假手术组、治疗组、对照组,每组10只。治疗组给补肾祛痰活血汤、对照组给消栓通络胶囊,正常组、模型组、假手术组给与相应量的双蒸馏水。采用线栓法复制脑缺血再灌注损伤模型,72 h后,干湿重法测定脑含水量反映脑水肿程度,用免疫组织化学方法测定损伤区Occludin、ZO-1蛋白的表达量,并对各结果进行相关性分析。结果 与正常组、假手术组比较,模型组、治疗组、对照组72 h时间点大鼠脑组织含水量较正常组、假手术组要增高一些,脑组织损伤区周围Occludin、ZO-1蛋白表达明显降低（P<0.01）。脑组织含水量与脑组织损伤程度正相关,脑组织损伤区周围Occludin、ZO-1蛋白与脑组织损伤程度呈负相关。结论 补肾祛痰活血汤对缺血性脑损伤发生后损伤区Occludin、ZO-1蛋白含量降低有抑制作用,抑制血脑屏障通透性增高,减轻脑水肿形成。     

Dietary glutamine supplementation enhances expression of ZO-1 and occludin and promotes intestinal development in Min piglets

Forty-eight Min piglets at 7 days of age were randomly divided into two groups which were fed with 0% and 0.8% glutamine, respectively. Supplementation with 0.8% l-glutamine, the average daily gain (ADG) were significantly increased, and the concentrations of glutamine, glutamate, arginine and citrulline in plasma were significantly improved (P?P?P?occludin mRNA and protein (P?相似文献   

团头鲂糖皮质激素受体基因组织表达分布及其在应激中的表达变化

为了解团头鲂糖皮质激素受体(GR)在应激反应中的调控机制,本研究以皮质醇注射模拟应激事件,采集组织样品,常规检测血糖、血清皮质醇水平;利用荧光定量PCR检测了gr在不同组织中的表达丰度及其参与调控的功能基因的表达变化;并通过常规石蜡切片开展了组织病理学研究。结果显示,gr1在脾脏、鳃、头肾等组织中有较高的表达量,gr2则在肝、垂体、肠等组织中具有较高的表达丰度。应激恢复过程中,下丘脑gr1表达量存在波动,gr2在0 h表达显著上调,gr1/gr2值逐渐增大;垂体中gr1和gr2均呈现先升后降的趋势,gr1/gr2值在2 h达到峰值水平;头肾中gr1表达量有波动,而gr2在0 h和2 h的表达量显著低于其他检测点的表达量,gr1/gr2值逐渐减小;肝脏中gr1的表达量在0 h和2 h的表达量显著高于其他检测点,gr2表达有上下波动的现象,gr1/gr2值有减小的趋势,而pepck表达则出现了显著上调,在2 h达到峰值;皮肤中gr1先升高后降低,gr2在0 h和2 h的表达量显著低于其他检测点,gr1/gr2值在2～8 h维持在较大值,而occ表达呈现先增加后降低的变化趋势;鳃中gr1与gr2均在2 h时发生了显著上调,gr1/gr2值在2～8 h维持在较大值,occ表达峰值出现在2 h。组织学研究显示鳃丝有增生现象,肾间组织中类淋巴细胞增多,其他所检视组织无明显病理改变。应激反应过程中gr在不同组织不同亚型间存在不同的表达变化,以及和不同组织器官中相关功能基因的相关性显示了GR在相关调控中的复杂性,而组织学研究结果则表明了应激反应存在诱发病理变化的风险。