Contamination, infection and inflammation control in an experimental mucosal cyst model using athymic nude mice
Year: 2007
Type: dissertation
Abstract: Various experimental cyst models have been developed in animals to study the epithelial-mesenchymal interactions and the etiology, pathogenesis, growth and behaviour of cysts.An artificial cyst model constructed from human vaginal mucosa in athymic nude mice has been suggested as an in vivo biotest system to study oral mucosal diseases.However, previous investigators have rarely provided information on the identification of microbiological contaminants and infection control.This study therefore identified the common pathogens and risk factors.The effects of Terramycin in drinking water and subcutaneous injections of Gentamicin (twice daily) were examined.The silk and nylon sutures were randomly used to construct the artificial cysts and stitch the skin wounds of mice.Forty-three male athymic nude mice (MFI nu nu) were implanted with human vaginal mucosal cysts under general anaesthesia with Ketamine [25mg/kg] and Medetomidine [0.5mg/kg].Cysts in 37 mice were recovered after 9 weeks of growth.Twenty-three cyst linings had retained the original structure of the vaginal epithelium.No marked difference was present between the thickness of 9-week old cyst linings and donor vaginal epithelium.The contaminants isolated from the skin of mice before implantation were mainly normal commensals of healthy experimental animals.Coagulase negative Staphylococci (CNS) were the most frequently isolated contaminats (58.1%) from the implanted cyst site after 9 weeks of growth, followed by Enterococcus faecalis (22.6%).There was no distinct difference in the number of cases with intact cyst formation between the Terramycin/ vitamin cocktail group and the control group.The frequency of poor wound healing and/or murine epidermis ingrowth was three times higher in iv animals stitched with silk sutures than in those cases where nylon sutures were used.The inflammation around silk sutures was generally more severe than that around nylon sutures.A foreign body reaction and acute inflammatory infiltrate usually surrounded the silk sutures.The loss of three mice was attributed to the high irritation of peracetic acid.It is concluded that CNS and Enterococci were the most common pathogens found in the cyst model.Gentamicin proved to be more efficient against Gram-negative contaminants than Terramycin.Poor wound healing and murine epidermis ingrowth were the highest risk factors for failure of the implants.Nylon suture is an appropriate non-absorbable suture for minimising infection around experimental cysts.The prevention of microbiological contamination is compromised when the isolators are used in a substandard animal room.High irritative disinfectants and substandard animal housing must be avoided.
Author: Meng Wang
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2268187501