聚苯乙烯微塑料对小鼠生长发育和肝脏脂质代谢的影响

Effects of polystyrene microplastics on growth and development and hepatic lipid metabolism in mice

背景:塑料作为耐用、廉价、易于制造的有机合成高分子材料被广泛应用,同时塑料耐高温、耐酸碱、耐腐蚀的特性使其在自然界难以降解,最终形成数量庞大的微塑料污染威胁人类身体健康。目的:探究微塑料暴露对小鼠生长发育和肝脏脂质代谢的影响。方法:20只雄性C57BL/6J小鼠适应性喂养1周后,采用随机数字表法分为正常组与微塑料组,每组10只,正常组小鼠予以普通饮食,自由饮水,饮用4周;微塑料组小鼠予以普通饮食,自由饮用1000μg/L的微塑料(聚苯乙烯)水,饮用4周。饮水2,4周后,检测小鼠体质量与抓力、血脂与肝肾功能、肝脏超声形态及病理形态与肝脏脂质沉积情况。结果与结论:①随着时间的延长,两组小鼠体质量逐渐增加,微塑料组小鼠饮水2,4周后的体质量大于正常组(P<0.05);随着时间的延长,正常组小鼠抓力逐渐升高,微塑料组小鼠抓力先降低后升高,微塑料组饮水4周后的抓力低于正常组(P<0.05);②肝脏超声检查显示,与正常组比较,微塑料组小鼠饮水2,4周后的肝脏超声回声信号增强;③苏木精-伊红染色显示,微塑料组小鼠饮水2,4周后的肝细胞形态无明显变化,但可见炎性细胞浸润;油红O染色显示,微塑料组小鼠饮水2,4周后肝脏可见明显脂质沉积;④与正常组比较,微塑料组小鼠饮水2周后的血清高密度脂蛋白胆固醇、三酰甘油、天门冬氨酸氨基转移酶水平均降低(P<0.05),饮水4周后的血清三酰甘油浓度降低(P<0.05);⑤结果表明,微塑料可能导致小鼠体质量增加、体力下降及肝脏脂质代谢异常。

BACKGROUND:Plastic as a durable,inexpensive,easy to manufacture organic synthetic polymer materials are widely used.At the same time,plastic resistance to high temperatures,acid and alkali resistance,corrosion-resistant properties make it difficult to degrade in nature,and ultimately forming a huge number of microplastic pollution threatening human health.OBJECTIVE:To investigate the effects of microplastic exposure on growth and development and hepatic lipid metabolism in mice.METHODS:Twenty C57BL/6J male mice were adaptively fed for one week,and then randomly divided into normal and microplastic groups(n=10 per group).Mice in the normal group were given a normal diet and water,for 4 weeks.Mice in the microplastic group were given a normal diet and free drinking of microplastic(polystyrene)water with a concentration of 1000μg/L,for 4 weeks.At 2 and 4 weeks of drinking,body mass and grip strength,blood lipids and liver and kidney function,ultrasonic morphology and pathological morphology of liver and lipid deposition were detected.RESULTS AND CONCLUSION:(1)With the extension of time,the body mass of mice in the two groups gradually increased,and the body mass of mice in the microplastic group was greater than that in the normal group after 2,4 weeks of drinking water(P<0.05).With the extension of time,the grip strength of mice in the normal group gradually increased,and the grip strength of mice in the microplastic group first decreased and then increased,and the grip strength of mice in the microplastic group was lower than that in the normal group after drinking water for 4 weeks(P<0.05).(2)Liver ultrasound examination showed that compared with the normal group,the ultrasonic echo signal of the liver in the microplastic group was enhanced after 2 and 4 weeks of drinking water.(3)Hematoxylin-eosin staining showed that the morphology of liver cells in the microplastic group did not change significantly after 2 and 4 weeks of drinking water,but inflammatory cell infiltration could be seen.Oil red O staining showed that obvious lipid deposition was observed in the liver of microplastic group after 2 and 4 weeks of drinking water.(4)Compared with the normal group,the levels of serum high density lipoprotein cholesterol,triacylglycerol,and aspartate aminotransferase in the microplastic group were decreased after 2 weeks of drinking water(P<0.05),and the serum triacylglycerol concentration was decreased after 4 weeks of drinking water(P<0.05).(5)These findings confirm that microplastics may cause weight gain,loss of physical strength,and abnormal hepatic lipid metabolism in mice.