摘要
目的:早在阿波罗11号任务中,宇航员携带月尘(lunar dust,LD)进入返回舱后出现眼部、皮肤和上呼吸道刺激症状,这引起了人们对其潜在生物毒性的关注。然而,LD通过消化系统暴露所造成的影响尚缺乏研究。本研究旨在评估月尘模拟物(lunar dust simulant,LDS)经消化系统暴露对小鼠肠道菌群、肠道、肝、肾、肺及骨骼造成的影响。方法:以8周龄C57BL/6J雌性小鼠为研究对象,使用LDS代替LD,选择陕西黄土代表地尘(Earth dust,ED)。将小鼠随机分成磷酸盐缓冲液(phosphate buffered saline,PBS)组、ED组(500 mg/kg)和LDS组(500 mg/kg),设置第7、14和28天3个暴露时长。每3 d灌胃1次,每次灌胃前称量小鼠体重。在干预结束后,采用16S核糖体RNA(ribosomal RNA,rRNA)测序技术分析小鼠粪便中肠道微生物多样性和组成;采用实时反转录聚合酶链反应(real-time reverse transcription PCR,real-time RT-PCR)检测肠道、肝、肺组织中炎症因子白细胞介素(interleukin,IL)-1β、IL-6和肿瘤坏死因子(tumor necrosis factor,TNF)-α的mRNA表达水平;采用苏木精-伊红(hematoxylin and eosin,HE)染色观察小鼠肺、肝和肠道的病理改变;采用糖原过碘酸-雪夫(periodic acid-Schiff,PAS)染色评估肠道黏膜屏障完整性,免疫组织化学染色检测黏蛋白2(mucin 2,MUC2)的表达情况;采集小鼠血液检测肝肾功能;采用微计算机断层扫描(micro-computed tomography,micro-CT)检测小鼠股骨骨量,免疫组织化学染色进行骨钙素(osteocalcin,OCN)染色来检测成骨细胞数目,抗酒石酸酸性磷酸酶(tartrate-resistant acid phosphatase,TRAP)染色检测破骨细胞数目;采用流式细胞术检测小鼠骨髓中免疫细胞的比例。结果:在暴露第10天,ED组和LDS组小鼠体重增长减缓,第22天和第28天时ED组和LDS组小鼠体重均明显低于PBS组(均P<0.05)。16S rRNA测序结果显示,在暴露第7天,LDS组小鼠粪便微生物物种丰富度和多样性均高于PBS组;与PBS组和ED组相比,LDS组小鼠粪便中脱铁杆菌门、脱硫弧菌门、弯曲菌门相对丰度升高,厚壁菌门相对丰度降低,其中盲肠螺杆菌的比例升高,约氏乳杆菌和鼠乳杆菌的比例降低。结肠HE与PAS染色结果显示LDS组黏膜结构破坏和杯状细胞减少更为严重;此外,免疫组化结果显示其MUC2表达也显著下调(P<0.05)。3组小鼠的肝脏HE染色结果均未见明显病理改变,且均无明显肝肾功能损伤。ED组和LDS组肺HE染色结果显示肺血管周围炎症细胞浸润增多。Real-time RT-PCR结果显示LDS组小鼠肺组织和肠道的炎症因子表达水平相较PBS组明显升高。Micro-CT结果显示,在暴露第28天,ED组和LDS组小鼠骨量较PBS组明显减低。免疫组织化学染色结果显示,ED组和LDS组小鼠成骨细胞减少,破骨细胞增加。流式细胞术结果显示LDS暴露第7天和第28天骨髓中巨噬细胞的比例较PBS组均明显降低(均P<0.05)。结论:LDS可引起肠道有益菌丢失和有害菌增加、肠道屏障损伤,以及肺部炎症反应、骨量丢失和骨髓免疫失衡。因此,在未来的月球任务中,应高度重视LD对健康的潜在危害;靶向补充有益菌以预防LD暴露所致的健康危害,或可成为一种具有应用前景的干预策略。
Objective:As early as the Apollo 11 mission,astronauts experienced ocular,skin,and upper airway irritation after lunar dust(LD)was brought into the return cabin,drawing attention to its potential biological toxicity.However,the biological effects of LD exposure through the digestive system remain poorly understood.This study aimed to evaluate the impact of digestive exposure to lunar dust simulant(LDS)on gut microbiota and on the intestine,liver,kidney,lung,and bone in mice.Methods:Eight-week-old female C57BL/6J mice were used.LDS was used as a substitute for lunar dust,and Shaanxi loess was used as Earth dust(ED).Mice were randomly divided into a phosphate buffered saline(PBS)group,an ED group(500 mg/kg),and a LDS group(500 mg/kg),with assessments at days 7,14,and 28.Mice were gavaged once every 3 days,with body weight recorded before each gavage.At sacrifice,fecal samples were analyzed by 16S ribosomal RNA(rRNA)sequencing;inflammatory cytokine expression[interleukin(IL)-1β,IL-6,and tumor necrosis factor alpha(TNF-α)]in intestinal,liver,and lung tissues was measured by real-time reverse transcription PCR(real-time RT-PCR);hematoxylin and eosin(HE)staining was performed on lung,liver,and intestinal tissues;Periodic acid-Schiff(PAS)staining was used to assess the integrity of the intestinal mucus barrier,and immunohistochemical staining was performed to evaluate the expression of mucin-2(MUC2).Serum biochemical tests assessed hepatic and renal function.Femoral bone mass was analyzed by micro-computed tomography(micro-CT);osteoblasts and osteoclasts were assessed by osteocalcin(OCN)and tartrate-resistant acid phosphatase(TRAP)staining.Bone marrow immune cell subsets were analyzed by flow cytometry.Results:At day 10,weight gain was slowed in ED and LDS groups.At days 22 and 28,body weight in both ED and LDS groups was significantly lower than controls(both P<0.05).LDS exposure increased microbial species richness and diversity at day 7.Compared with the PBS and ED groups,mice in the LDS group showed increased relative abundance of Deferribacterota,Desulfobacterota,and Campylobacterota,and decreased Firmicutes,with increased Helicobacter typhlonius and reduced Lactobacillus johnsonii and Lactobacillus murinus.HE and PAS staining of the colon showed that mucosal structural disruption and goblet cell loss were more severe in the LDS group.In addition,immunohistochemistry revealed a significant downregulation of MUC2 expression in this group(P<0.05).No obvious pathological alterations were observed in liver HE staining among the 3 groups,and none of the groups exhibited notable hepatic or renal dysfunction.HE staining of the lungs in the ED and LDS groups showed increased perivascular inflammatory cell infiltration(both P<0.05).Conclusion:LDS exposure via the digestive route induces gut dysbiosis,intestinal barrier disruption,pulmonary inflammation,bone loss,and bone marrow immune imbalance.These findings indicate that LD exposure poses potential health risks during future lunar missions.Targeted restoration of beneficial gut microbiota may represent a promising strategy to mitigate LD-related health hazards.
作者
陈一霄
刘祎伟
何诗月
龚晓晓
程琦云
陈娅
胡新月
王振兴
谢辉
CHEN Yixiao;LIU Yiwei;HE Shiyue;GONG Xiaoxiao;CHENG Qiyun;CHEN Ya;HU Xinyue;WANG Zhenxing;XIE Hui(Department of Orthopaedic Surgery,Xiangya Hospital,Central South University,Changsha 410008;Movement System Injury and Repair Research Center,Xiangya Hospital,Central South University,Changsha 410008;Department of Respiratory and Critical Care Medicine,Branch of National Clinical Research Center for Respiratory Disease,Xiangya Hospital,Central South University,Changsha 410008;Department of Pathology,Xiangya School of Basic Medical Sciences,Central South University,Changsha 410078;National Clinical Research Center for Geriatric Disorders(Xiangya Hospital),Changsha 410008,China)
出处
《中南大学学报(医学版)》
北大核心
2025年第8期1290-1305,共16页
Journal of Central South University (Medical Science)
基金
湖南省科技厅湖湘青年英才项目(2023RC3075)
中南大学中央高校基本科研业务费专项资金(2024ZZTS0887)。
关键词
探月工程
月尘模拟物
肠道菌群
肠道屏障
骨质疏松
肺炎
lunar exploration
lunar dust simulant
gut microbiota
intestinal barrier
osteoporosis
pneumonia
