title: [Effect of axonal developmental disorders in the corpus callosum on the neurological function after birth in septic neonatal rats].
abstract: OBJECTIVE
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Critical Care and Emergency, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, Guangdong, China (Deng YY, Han QP, Chen MM, Zeng HK); Department of Rheumatology, the First Affiliated Hospital, Shantou University Medical College, Shantou 515000, Guangdong, China (Shen FC). Corresponding author: Deng Yiyu, Email: yiyudeng666@163.com.
authors.forename: Yiyu
authors.initials: Y
authors.lastname: Deng
authors.forename: Qianpeng
authors.initials: Q
authors.lastname: Han
authors.forename: Fengcai
authors.initials: F
authors.lastname: Shen
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Chen
authors.forename: Hongke
authors.initials: H
authors.lastname: Zeng
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology*; D003337:Corpus Callosum / Q000502:physiology*; D008070:Lipopolysaccharides; D000071074:Neonatal Sepsis / Q000473:pathology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D008070:Lipopolysaccharides