目的：探讨表皮葡萄球菌（Staphylococcus epidermidis，SE）感染对不同日龄新生小鼠的影响。方法出生后第1天（PND1）和第3天（PND3）新生小鼠共60只，分为SE组、生理盐水（NS）组、对照组，每组20只。SE组静脉注射108/ml的SE 50μl，NS组给予等量NS，对照组不作任何处理。第14天时取脑、肝、脾称重，脑组织石蜡包埋后连续切片，用于微管相关蛋白-2（microtubule associated protein-2，MAP-2）和髓鞘碱性蛋白（myelin basic protein，MBP）免疫组化染色，并计算脑灰质和白质面积和体积。结果 PND1小鼠SE组的死亡率为60.0%，NS组为40.0%，差异无统计学意义（P>0.05）；PND3小鼠SE组的死亡率10.0%，NS组无死亡，差异无统计学意义（P>0.05）。PND1和PND3组的体质量，体质量增长，肝、脾重量及脏器系数的差异无统计学意义（P均>0.05）。PND1小鼠SE组的脑灰质面积和体积明显低于NS组，脑白质面积和体积也低于NS组，差异有统计学意义（P均<0.05）；PND3小鼠SE组脑灰质及脑白质的面积和体积与NS组的差异无统计学意义（P均>0.05）。结论 SE感染可致PND1小鼠的脑组织损伤，而对PND3小鼠无明显影响。%Objectives To study the influence of Staphylococcus epidermidis (SE) on the neonatal mice of different ages. Methods A total of 60 neonatal mice including postnatal day 1(PND1) and postnatal day 3(PND3) were divided into SE group, normal saline (NS) group and control group, with 20 mice each. Mice in SE group were intravenously injected with 50μl SE (108/ml). Mice in NS group were given 50μl NS and mice in control group was not intervened. On postnatal day 14, the brain, liver and spleen obtained from mice were weighted. Serial sections of paraffin-embedded brain tissue were used for the detec-tion of microtubule associated protein-2 (MAP-2) and myelin basic protein (MBP) by immumohistochemical staining, and then the areas and volumes of grey and white matter were calculated. Result The mortality of PND1 mice in SE and NS group was 60.0%and 40.0%, respectively, and there was no difference between two groups (P>0.05). The mortality of PND3 mice in SE and NS group was 10.0%and 0.0%, respectively, and there was no difference between two groups (P>0.05). There were no dif-ferences in body weight, body weight gain, spleen and liver weights and organ coefficient between PND1 and PND3 mice (P>0.05). In PND1 mice, the areas and volumes of grey and white matter were significantly smaller in SE group than those in NS group (P<0.05). However, in PND3 mice, there was no differences in areas and volumes of grey and white matter between SE and NS group (P>0.05). Conclusions SE infection can result in brain injury in PND1 mice, but has no effect on brain tissues of PND3 mice.
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