大气污染物颗粒物黑碳对小鼠泪膜功能的损害作用

Detrimental effects of soot from air pollution on tear film function in mice

目的观察不同浓度大气污染物颗粒物来源黑碳混悬溶液点眼对小鼠泪膜功能的损害作用。方法选取28只6~8周龄SPF级雄性BALB/c小鼠,按照随机数字表法随机平均分为0.5 mg/ml组、1 mg/ml组、5 mg/ml组和对照组,每组7只,分别采用0.5 mg/ml、1 mg/ml、5 mg/ml黑碳混悬液和磷酸盐缓冲溶液点右眼,每次4μl,每天3次。于处理前及处理后4、7、10、14 d对小鼠行泪液分泌量、泪膜破裂时间(TBUT)检测及角膜荧光染色(CFS)和结膜充血情况评估。结果在处理后第14天,0.5 mg/ml组、1 mg/ml组、5 mg/ml组和对照组泪液分泌量分别为(2.74±0.74)、(2.73±0.76)、(2.31±0.67)和(5.31±0.36)mm,TBUT分别为(4.87±0.28)、(4.00±0.76)、(3.23±0.43)和(6.22±0.22)s,CFS分别为4(3,4)、5(5,6)、7(7,8)和0(0,1)分,结膜充血评级分别为2(2,3)、2(2,3)、3(2,3)和0(0,1)。0.5 mg/ml组、1 mg/ml组、5 mg/ml组和对照组不同时间点泪液分泌量总体比较,差异均有统计学意义(F_(组别)=83.325,P<0.001;F时间=86.551,P<0.001;F交互作用=5.181,P<0.001),其中0.5 mg/ml组、1 mg/ml组、5 mg/ml组各时间点泪液分泌量均明显低于相应时间点对照组,组内处理后4、7、10、14 d泪液分泌量均明显低于处理前,差异均有统计学意义(均P<0.05)。各组不同时间点TBUT总体比较,差异均有统计学意义(F_(组别)=75.130,P<0.001;F时间=56.265,P<0.001;F交互作用=6.103,P<0.001),其中0.5 mg/ml组、1 mg/ml组和5 mg/ml组各时间点TBUT明显短于相应时间点对照组,组内处理后4、7、10、14 d TBUT均较处理前明显缩短,1 mg/ml组和5 mg/ml组处理后14 d TBUT均较处理后4、7、10 d明显缩短,差异均有统计学意义(均P<0.05)。各组不同时间点CFS评分和结膜充血分级比较差异均有统计学意义,组别与测量时间交互作用差异均无统计学意义(CFS:H_(组别)=59.249,P<0.001;H时间=49.959,P<0.001;H_(交互作用)=15.980,P=0.192.结膜充血分级:H_(组别)=57.622,P<0.001;H时间=42.062,P<0.001;H_(交互作用)=12.565,P=0.401),其中0.5 mg/ml组、1 mg/ml组和5 mg/ml组处理后各时间点CFS评分和结膜充血分级明显高于相应时间点对照组,组内处理后4、7、10、14 d CFS评分和结膜充血分级均明显高于处理前,差异均有统计学意义(均P<0.05)。结论大气污染物颗粒物来源黑碳眼表暴露可造成BALB/c小鼠泪膜功能的损伤和眼表炎症,并在一定程度上对眼表的损伤呈浓度及时间依赖性。

Objective To observe the detrimental effect of airborne black carbon suspension solution of different concentrations on the tear film function of mice.Methods Twenty-eight SPF-grade male BALB/c mice,aged 6-8 weeks,were randomly divided into four groups,0.5 mg/ml group,1 mg/ml group,5 mg/ml group,and control group,with 7 mice in each group.The right eyes of mice were dropped by 4μl of 0.5 mg/ml,1 mg/ml,5 mg/ml black carbon suspension,or phosphate buffer solution,3 times a day according to grouping.Tear volume,tear break-up time(TBUT),corneal fluorescein staining(CFS),and conjunctival congestion were assessed before treatment and 4,7,10,and 14 days after treatment.The use and care of experimental animals complied with the Regulations for Administration of Laboratory Animals in Peking Union Medical College Hospital(No.XHDW-2022-053).Results At 14 days after treatment,the tear volumes of 0.5 mg/ml group,1 mg/ml group,5 mg/ml group and control group were(2.74±0.74),(2.73±0.76),(2.31±0.67),and(5.31±0.36)mm,respectively.TBUT of the four groups were(4.87±0.28),(4.00±0.76),(3.23±0.43),and(6.22±0.22)seconds,respectively.CFS of the four groups were 4(3,4),5(5,6),7(7,8)and 0(0,1)points,respectively.Conjunctival congestion grades of the four groups were 2(2,3),2(2,3),3(2,3)and 0(0,1),respectively.There were statistically significant differences in tear volume among the four groups at different time points(F_(group)=83.325,P<0.001;F_(time)=86.551,P<0.001;F interaction=5.181,P<0.001).Before and at each time point after treatment,tear volumes were significantly lower in 0.5 mg/ml group,1 mg/ml group,and 5 mg/ml group than in control group,and tear volumes in 0.5 mg/ml group,1 mg/ml group,and 5 mg/ml group were significantly lower at 4,7,10,and 14 days after treatment than before treatment(all at P<0.05).There were statistically significant differences in TBUT among the four groups at different time points(F_(group)=75.130,P<0.001;F_(time)=56.265,P<0.001;F interaction=6.103,P<0.001).Before and at each time point after treatment,TBUT was significantly shorter in 0.5 mg/ml group,1 mg/ml group,and 5 mg/ml group than in control group,and the TBUT was significantly shorter in 0.5 mg/ml group,1 mg/ml group,and 5 mg/ml group at 4,7,10,and 14 days after treatment than before treatment,shorter in 1 mg/ml group and 5 mg/ml group at 14 days after treatment than 4,7 and 10 days after treatment(all at P<0.05).There were statistically significant differences in CFS score and conjunctival congestion grades among the four groups at different time points,but the interactions between concentration group and measurement time were not statistically significant(CFS:H_(group)=59.249,P<0.001;H time=49.959,P<0.001;H interaction=15.980,P=0.192.conjunctival congestion grade:H_(group)=57.622,P<0.001;H time=42.062,P<0.001;H interaction=12.565,P=0.401).Before and at each time point after treatment,the CFS scores and conjunctival congestion grades were significantly higher in 0.5 mg/ml group,1 mg/ml group,and 5 mg/ml group than in control group,and CFS scores and conjunctival congestion grades were significantly higher in 0.5 mg/ml group,1 mg/ml group,and 5 mg/ml group at 4,7,10,and 14 days after treatment than before treatment(all at P<0.05).Conclusions The exposure of airborne black carbon on the ocular surface causes damage to tear film function and ocular surface inflammation in BALB/c mice.Within a certain concentration and time range,the tear secretion decreases,TBUT shortens,CFS and conjunctival congestion increase.