大肠埃希菌感染小鼠外周血中性粒细胞与淋巴细胞比值的动态变化

Dynamic changes of neutrophil/lymphocyte ratio in peripheral blood of mice infected by Escherichia coli

目的通过观察大肠埃希菌感染小鼠模型不同时间段外周血中,中性粒细胞与淋巴细胞比值的动态变化,分析外周血中中性粒细胞/淋巴细胞比值与大肠埃希菌感染炎症程度的关系,以及中性粒细胞与淋巴细胞在大肠埃希菌感染时的可能作用机制。方法将麦氏浊度为2.73约为1×109CFU/m L大肠埃希菌通过尾静脉注射建立ICR小鼠感染模型44只、空白对照4只及阴性对照4只。实验组按1、3、6、12、24、48、72、96、120、144和168 h,共11个时间段,每次取4只小鼠,抽取外周血800μL,利用SYSMEX2100检查白细胞总数、中性粒细胞计数、淋巴细胞计数、中性粒细胞/淋巴细胞比值变化情况。结果大肠埃希菌ICR小鼠感染组1~24 h白细胞总数比对照组降低(0.01<P<0.05),第2天时与对照组比较差异无统计学意义,第3天至第7天白细胞总数比对照组高且差异有统计学意义(P<0.01),并在第7天时略有回落;感染组中性粒细胞计数值在感染12 h到第7天比对照组高,差异有统计学意义;中性粒细胞/淋巴细胞比值对照组为0.06±0.03,感染1 h为0.07±0.04,与对照组比较差异无统计学意义(P>0.05),3 h、6 h两组与对照组比较差异有统计学意义(0.01<P<0.05),12 h开始到第7天感染组与对照组比较差异有统计学意义,且第7天时为最高值(1.52±0.38)。结论中性粒细胞/淋巴细胞比值,比白细胞总数计数、中性粒细胞计数在大肠埃希ICR小鼠感染模型组中判断小鼠感染状况敏感,中性粒细胞/淋巴细胞比值结合白细胞总数计数、中性粒细胞计数能为临床大肠埃希菌感染的状况提供更灵敏的诊断参考数据,且易在临床推广。

Objective To analyze the relationship between neutrophil/lymphocyte ratio in peripheral blood and inflammation degree in mice infected by Escherichia coli, and the possible mechanism of action of neu- trophil and lymphocyte upon being infected by Escherichia coll. Methods 44 ICR mice were injected with 1 ×10^9 CFU/mL Escherichia coli to build the models, with 4 mice as the blank controls and 4 as the negative controls. The quantities of white blood cells, neutrophils, lymphocytes and neutrophil/lymphocyte ratio were detected by using SYSMEX2100 at eleven time points. Results The quantity of white blood cells in the model group was lower than that in control group （0.01〈P〈0.05） in 1 to 24 hours after infection, showed no obvious difference from that in control group on the second day, was significantly higher than that in con- trol group from the third day to the seventh day, and then declined on the seventh day. The quantity of neu- trophils was statistically higher than that in control group from the 12th hour to 7th day. The neutrophil/ lymphocyte ratio in control group was 0.06±0.03, not obviously different from the 0. 074-0.04 in the mod el group at 1 hour after infection （P〉0.05） but from those at 3 hours and 6 hours after infection （0.01〈 P〈0.05） ; and the ratios in the model group were significantly different from that in the control group from the 12th hour to the 7th day after infection, which reached the highest value at Day 7 （1.52 ±0.38） . Conclusion Compared to quantities of white blood cells and neutrophil, neutrophil/lymphocyte ratio is a more sensitive indicator for Escherichia coli infection in mice, and when used in combination with the for- mer, it can provide more sensitive reference data for the clinical diagnosis of Escherichia coli infection.