大气可吸入颗粒物对大鼠心率变异性的影响

目的研究可吸入颗粒物对大鼠心率变异性的影响。方法24只SD大鼠,均为雄性,体重150~200 g。随机分为两组(实验组、对照组),每组12只。实验组大鼠按25 mg(1 ml)/kg体重经气管内缓慢注入颗粒物生理盐水悬液染毒,每周染毒2次,连续染毒4周;对照组以生理盐水代替颗粒物悬液。大鼠麻醉后经皮下引导电极连续采集心电信号,计算SDNN和r-MSSD。统计学处理采用SPSS统计学软件,组间比较用t检验或方差分析,P0.05为差异有统计学意义。结果2组大鼠首次和末次染毒之后30 min的心率均较染毒之前明显下降;两组大鼠首次染毒之前和末次染毒之前的心率差异无统计学意义;两组大鼠首次染毒之后和末次染毒之后30 min的心率差异无统计学意义。两组大鼠首次染毒之前和首次染毒之后30 min的心率变异性差异无统计学意义;末次染毒之前和末次染毒之后30 min的心率变异性差异无统计学意义;实验组末次染毒之前和末次染毒之后30min的心率变异性分别较首次染毒之前和首次染毒之后30 min时明显下降(P0.05);与对照组比较,实验组末次染毒之前和染毒之后30 min的心率变异性明显下降(P0.05)。结论本研究表明可吸入颗粒物能够导致心率变异性的降低。

Effect of particulate matter on heart rate variability in healthy rats

Objective To assess the effects of particulate matter on heart rate variability in healthy rats.Methods Twenty four healthy SD rats were instilled with solution of saline and particulate matter（25 mg/kg body weight,twice a week）respectively for four weeks.Particulate matter was collected in glass fiber filters using a high-volume sampler.Electrodes for obtaining electrocardiograms were implanted subcutaneously in a lead II configuration.Heart rate,the standard deviation of the intervals between normal beats（SDNN） and root mean square of standard diaviation of NN intervals（r-MSSD） were assessed immediately before and 30 min after treatment at the first and the last instillation.Results There was no significant difference in heart rates between two groups.However,the SDNN and r-MSSD decreased significantly after four weeks of instillation with particular matter in the particulate matter group than those after four weeks of instillation with saline in the control group.Conclusion Particulate matter induced the reduction of heart rate variability in healthy rats.