Construction of a rat model with open traumatic brain injury combined with intracranial infection after immersion in seawater

HOU Pengwei; YANG Yang; YE Dan; ZHANG Hao; CAI Shumei; WEI Liangfeng; WANG Shousen

Abstract：Objective By constructing a rat model of open traumatic brain injury combined with intracranial infection after immersion of seawater,we aimed to detect the incidence rate and bacterial species of intracranial infection in rats following immersion of natural seawater.Methods A total of 17 000ml seawater was collected from Guanyinao port,Pingtan,Fujian Province,for bacterial culture,metagenome sequencing and animal model making.Sixty-six male SD rats were randomly divided into 3 groups:TBI+sterile group with artificial seawater immersion(ASI)(n=6)、control(sham)+group with natural seawater immersion(NSI)(n=30)and TBI+NSI group(n=30).Subsequently,cerebrospinal fluid was collected from the cisterna magna for bacterial culture,and the infection rate and pathogenic bacteria species were counted according to outcomes of the culture.Results Outcomes of seawater metagenome sequencing indicated that structures at genus level of bacterial flora were Vibrio,Pseudoxanthomonas,Pelagibacter,Psychrophilic bacteria,etc.There were Vibrio parahaemolyticus,Vibrio alginolyticus,Vibrio vulnificus,Escherichia coli,Staphylococcus aureus,Klebsiella pneumoniae and so on in the sample seawater according to above-mentioned bacterial cultivation of seawater.In the TBI+NSI group,quantities of subjects infected with Vibrio parahaemolyticus,Escherichia coli,Vibrio alginolyticus,and Pseudomonas aeruginosa were 6,6,5 and 1 respectively,Some rats showed mixed infections(3).A total of 21 mice were infected in the TBI+NSI group,with an infection rate of 70％(21/30),compared to the sham+NSI group(P＜0.01).In the sham+TBI group,numbers of subjects infected with Vibrio parahaemolyticus,Escherichia coli,Vibrio alginolyticus,and Klebsiella pneumoniae were 2,1,1 and 1 respectively,with the infection rate of 17％(5/30).By contrast,SD rats in the TBI+ASI group were not infected.Conclusion In this study,a rat model of open craniocerebral injury combined with intracranial infection after seawater immersion was successfully established,and the fact that the majority of pathogenic bacteria in open traumatic brain injury combined with intracranial infection after seawater immersion were Gram-negative bacteria was preliminarily defined.Additionally,involved bacteria were primarily Marine Vibrio and intestinal flora.