人工模拟寒冷环境对呼吸道合胞病毒感染幼鼠肺组织中病毒载量及肺损伤的影响

Effects of artificial simulated cold environment on viral load and lung injury in lung tissue of young rats with respiratory syncytial virus infection

目的探讨寒冷环境因素对感染呼吸道合胞病毒(RSV)幼龄大鼠肺组织中RSV载量及肺损伤的影响。方法选取18只SD幼龄大鼠,随机分为对照组、RSV感染组、RSV感染+寒冷环境组,每组6只。对照组幼鼠给予生理盐水滴鼻;RSV感染组幼鼠给予RSV滴鼻感染;RSV感染+寒冷环境组幼鼠给予RSV滴鼻感染后4 h放入制备寒冷环境气候的人工气候箱刺激7 d。实验结束后,RT-PCR法检测各组大鼠肺组织中病毒载量,根据肺湿干重计算肺湿干比,苏木素-伊红染色(HE染色)法观察肺组织病理改变并计算肺组织病理评分,ELISA法检测肺泡灌洗液中白细胞介素-8(IL-8)、肿瘤坏死因子-α(TNF-α)含量。结果RSV感染组、RSV感染+寒冷环境组大鼠肺组织中RSV载量、肺湿干比、肺组织病理损伤评分及肺泡灌洗液中IL-8、TNF-α含量均明显高于对照组(P均<0.05),且RSV感染+寒冷环境组均明显高于RSV感染组(P均<0.05)。对照组肺组织未见异常变化;RSV感染组肺泡壁轻度或中度充血、水肿,管腔内可见炎性渗出物;RSV感染+寒冷环境组肺泡壁重度充血、水肿,管腔内见大量炎性渗出物。结论鼻腔滴鼻RSV可成功建立幼鼠RSV肺炎模型;寒冷环境下RSV感染肺组织病毒载量更高,肺组织损伤更为明显,肺损伤相关细胞因子含量明显增高。

Objective It is to investigate the effects of cold environmental on the respiratory syncytial virus(RSV)load and lung injury in lung tissue of young rats with RSV infection.Methods Eighteen young SD rats were randomly divided into control group,RSV infection group,RSV infection+cold environment group,with 6 rats in each group.The young rats in the control group were given normal saline by nasal drip,the young rats in RSV infection group were infected with RSV by RSV nasal drip,the young rats in RSV infection+cold environment group were put into the artificial climate box to prepare cold environment climate stimulation for 7 days after RSV infection.After the experiment,the viral load in the lung tissue of rats in each group was detected by RT-PCR method,the lung wet-dry ratio was calculated according to the lung wet-dry weight,the lung pathological changes were observed and the lung pathological score was calculated by hematoxylin-eosin staining(HE staining)method,and the contents of interleukin-8(IL-8)and tumor necrosis factor-ɑ(TNF-ɑ)in the alveolar lavage fluid were measured by ELISA method.Results The RSV load,lung wet-dry ratio,lung pathological injury scores and the contents of IL-8 and TNF-ɑin alveolar lavage fluid in RSV infection group and RSV infection+cold environment group were significantly higher than those in the control group(all P<0.05),and these indexes in the RSV infection+cold environment group were significantly higher than those in RSV infection group(all P<0.05).No abnormal change in lung tissue was found in the control group;In RSV infection group,the alveolar wall was slightly or moderately congested and edematous,and inflammatory exudates could be found in the lumen;In RSV infection+cold environment group,the alveolar wall was severely congested and edematous,and a large number of inflammatory exudates were found in the lumen.Conclusion RSV intranasal drip can successfully establish RSV pneumonia model in young rats,the viral load of RSV infected lung tissue is higher,the lung tissue injury is more obvious,and the content of cytokines related to lung injury is significantly higher in cold environment.