摘要目的：观察脓毒症新生大鼠胼胝体内轴突发育情况，探讨其对后期神经功能的影响。方法按随机数字表法将出生1d的SD大鼠分为对照组和脓毒症组，每组24只。采用腹腔注射脂多糖（LPS）1mg/kg的方法制备脓毒症模型，对照组给予等量磷酸盐缓冲液（PBS）。两组分别于制模后7、14、28d处死幼鼠取大脑胼胝体，应用免疫荧光及蛋白质免疫印迹试验（WesternBlot）检测胼胝体内神经纤维丝蛋白重、中、轻链（NFH、NFM、NFL）的表达；28d时于电镜下观察胼胝体内轴突形态及数量，原位杂交实验观察胼胝体内髓鞘碱性蛋白（MBP）的阳性细胞数。结果脓毒症组制模后7、14、28d胼胝体内NFH、NFM、NFL免疫荧光表达强度较对照组明显减弱，WesternBlot结果也显示，NFH、NFM、NFL蛋白表达均较对照组明显降低〔NFH（灰度值）：7d为0.16±0.03比0.34±0.04，14d为1.75±0.11比2.42±0.17，28d为3.39±0.25比5.11±0.23；NFM（灰度值）：7d为0.34±0.04比0.53±0.04，14d为0.74±0.04比1.12±0.07，28d为0.92±0.06比1.52±0.07；NFL（灰度值）：7d为0.12±0.02比0.26±0.14，14d为0.32±0.03比0.81±0.04，28d为0.85±0.08比1.81±0.05；P＜0.05或P＜0.01〕。28d时，对照组胼胝体内轴突发生了明显的髓鞘化，郎飞节清晰可见、结构完整、边缘光滑；脓毒症组胼胝体内髓鞘化轴突数明显减少，轴突郎飞节明显受损，MBP阳性细胞数较对照组明显减少（个/LP：23.67±3.21比35.00±3.61，P＜0.01）。结论脓毒症新生幼鼠生后28d胼胝体内轴突发育受损，导致轴突低髓鞘化，可影响后期的神经功能。

abstractsObjective To observe the axonal development in the corpus callosum of septic neonatal rats, and its effect on the neurological function after birth. Methods Forty-eight 1-day-old Sprague-Dawley (SD) rats were randomly divided into two groups: control group and sepsis group, with 24 rats in each group. The rat model of sepsis was reproduced by intraperitoneal injection of 1 mg/kg lipopolysaccharide (LPS), and the rats in control group were injected with an equal volume of phosphate buffered saline (PBS). The corpus callosum in brain was harvested at 7, 14, and 28 days after model reproduction, and double immunofluorescence staining and Western Blot were used to observe the expression of neurofilament heavy chain (NFH), neurofilament medium chain (NFM) and neurofilament light chain (NFL) in the corpus callosum. The morphology and number of axon were observed in the corpus callosum of rats at 28 days using electron microscopy. The number of myelin basic protein (MBP) positive cells in the corpus callosum of rats was determined by in situ hybridization. Results The immunofluorescence intensities of NFH, NFM, and NFL in the corpus callosum of rats at 7, 14, and 28 days after model reproduction in sepsis group were significantly lower than those of control group. In addition, it was revealed by Western Blot results that the protein expression levels of NFH, NFM, and NFL in sepsis group were significantly lower than those of control group [NFH (gray value): 0.16±0.03 vs. 0.34±0.04 at 7 days, 1.75±0.11 vs. 2.42±0.17 at 14 days, 3.39±0.25 vs. 5.11±0.23 at 28 days; NFM (gray value): 0.34±0.04 vs. 0.53±0.04 at 7 days, 0.74±0.04 vs. 1.12±0.07 at 14 days, 0.92±0.06 vs. 1.52±0.07 at 28 days; NFL (gray value): 0.12±0.02 vs. 0.26±0.14 at 7 days, 0.32±0.03 vs. 0.81±0.04 at 14 days, 0.85±0.08 vs. 1.81±0.05 at 28 days; P < 0.05 or P <0.01]. In the control group, an obvious myelination was found in the corpus callosum of rats on the 28th day after the birth, and the nodes of Ranvier were clearly distinguishable, with intact structure and smooth edges. The number of myelinated axons was reduced and the nodes of Ranvier were impaired in the corpus callosum of rats at 28 days after LPS injection. The expression of MBP in the corpus callosum of rats at 28 days after LPS injection was obviously decreased compared with control group (cells/LP: 23.67±3.21 vs. 35.00±3.61, P < 0.01). Conclusion The axonal development in the corpus callosum of septic neonatal rats on the 28th day after the birth was impaired, and lead to reduced myelination and further deterioration of neurological function.