含葡聚糖颗粒物暴露致小鼠肺部GSNO还原酶活化的研究

动物实验和体外研究都已表明,空气中有机颗粒物可引起肺部炎症反应,该反应的显著特点为细胞因子表达上调和分泌增多.葡聚糖是霉菌和细菌代谢及裂解的产物,当颗粒物受到霉菌和细菌污染之后,就会含有葡聚糖.最近的研究表明,含葡聚糖颗粒物的暴露会影响鼻腔和肺部的功能,并伴随炎症反应.然而,含葡聚糖颗粒物的暴露对一氧化氮合酶(NOS)和亚硝基谷胱甘肽还原酶(GSNOR)的影响仍不太清楚.本研究旨在检测含葡聚糖颗粒物暴露对呼吸道中NO信号通路的影响.本实验力小鼠被分别暴露于20μL PBS(空白组),20μL浓度为25μg/20μL的OVA和20μL浓度为100μL/20μL的含葡聚糖颗粒物环境中,暴露持续12d.暴露结束后在肺组织匀浆中检测NOS和GSNOR的活性.同时测定肺组织中谷胱甘肽(GSH)浓度和SOD活性用以评估氧化应激水平.另外,检测肺组织中的IL–6浓度确定炎症反应的发生与否.结果显示,12天OVA和葡聚糖颗粒物暴露并未明显影响NOS活性、GSH含量、SOD活性和IL-6浓度.然而,含葡聚糖颗粒物12d的暴露却明显增加GSNOR的活性和表达.我们的研究结果表明,含葡聚糖颗粒物暴露会激活呼吸道中的GSNOR,但不激活NOS.由于GSNOR在NO信号通路中起着举足轻重的作用,我们的研究结果具有一定的临床重要性.

Induction of GSNO Reductase in the Lungs of Mice Exposed to Glucan-Spiked Dust

Both animal experiment and in vitro studies have suggested that airborne organic dusts may induce inflammatory responses in the lungs,characterized by typical patterns of cytokine up-regulation and secretion.Glucan is the product of mildew and bacteria’s metabolism and cracking.When the particulate is polluted by mildew and bacteria,it will contain beta-glucan.Recent work showed that exposure to glucan-spiked dust might influence nasal and pulmonary function,without an accompanying inflammatory response.However,effects of glucan-spiked dust exposure on NOS and GSNO reductase（enzymes important to NO signaling） remain less clear.This study aims to determine the effects of simultaneous exposure to glucan-spiked dust on NO signaling pathway in the airway.Mice were exposed to 20μL PBS（controls）,20 μL 25 μg/20 μL OVA and 20 μL 100 μg/20 μL glucan-spiked dust,respectively,daily for 12 days.NOS and GSNO reductase activity were measured in lung homogenate.Glutathione concentration and SOD activity in lung tissue were also determined to evaluate changes in oxidative stress.IL-6 concentration was measured in lungs to quantify the inflammatory response.Results showed that 12 day OVA and glucan-spiked dust exposure did not significantly influence NOS activity,GSH concentration,SOD activity,or IL-6 concentration.An insignificant increase in GSNOR activity and expression was observed in 12 day OVA-exposed mice,whereas glucan-spiked dust exposure significantly increased GSNOR activity and expression.Our results suggested that repeated glucan-spiked dust exposure to the airway could activate GSNO reductase but not NOS.Since GSNO reductase plays a pivotal role in NO signaling,these results may have clinical reference.