Characters of bacterial growth in wound cavity and peripheral tissue in animals with crainocerebral injury under hyperthermia and high-humidity / 中国组织工程研究

ABSTRACT

BACKGROUND:Crainocerebral missile wound (CMW) is the common severe trauma of war. Environmental factor is the important factor that aggravates the development of sickness and threatens the life of the sick and wounded at early stage. The study on basic theory and treatment of CMW under hyperthermia and high-humidity is the major task in military medicine.OBJECTIVE: To observe the characters of bacterial growth in wound cavity and peripheral tissue after CMW in cats under hyperthermia and high-humidity so as to provide the reference data to the tissue repair and its functional recovery in CMW.DESIGN: Randomized controlled experiment.SETTING: Surgery Department of Neurology in Zhujiang Hospital affiliated to Southern Medical University(First Military Medical University).MATERIALS The experiment was performed in Department of Tropical Medicine and Hygiene in Southern Medical University from April to May 2003. In the experiment, 24 hybrid cats were employed, of clean grade, of either sex, body-weighted (2.5±0.2) kg, provided from Experimental Animal Center of Southern Medical University. The animals were randomized into 4 groups, named the control at common temperature (5 cats), common temperature group (8 cats), hyperthermia and high-humidity group (8 cats) and blank control (3 cats).METHODS: After weighted, the cat was injected abdominally with 30 g/L pentobarbitol sodium solution at 30 mg/kg. After successful establishment of craniocerebral blindgut wound model, in common temperature group, the cats were placed in simulated climatic cabin at 25 ℃ and 50% relevant humidity for 6 hours and in hyperthermia and high-humidity group, the cats were placed in the hyperthermia and high-humidity environment for 6 hours. With biopsy, the fragmented brain tissue in wound tract and the brain tissue on the wall of wound tract far from 0-5 mm and 5-10 mm were collected and preparedinto successively natural solution and homogenate, and counting was done in 24 hours of bacterial culture to calculate bacterial content in wound cavity and peripheral tissue. In blank control, the cats were sacrificed with anesthesia and the material was collected directly, the rest steps were same as the control at common temperature.MAIN OUTCOME MEASURES: Bacterial content in wound cavity and peripheral tissue in each group.RESULTS: Totally 23 animals were employed in outcome analysis. Bacterial contents in same regions were different remarkably in different groups (F=171.423, P=0.000). It was indicated in paired comparison that significant difference happens between the control at common temperature, common temperature group and hyperthermia and high-humidity group and blank control successively (P ＜ 0.01). The difference was not significant in the comparison among the control at common temperature, common temperature group and hyperthermia and high-humidity group (P ＞ 0.05). Bacterial contents at different distances from the wound cavity were different remarkably in each group (F=14.865, P = 0.000).CONCLUSION: Hyperthermia and high-humidity does not impact significantly the bacterial growth of CMW in 6 hours and bacterial reproduction has not entered high-rate increasing stage yet, due to which, it is still safe for debridement repair.