Chapter 25 - Translocation of Gut Bacteria During Trauma

Abstract

This chapter investigates bacterial translocation in animal models of rats and mice subjected to thermal injury, hemorrhagic shock, endotoxemia, or zymosan challenge. To maintain a stable indigenous gut flora, all SPF animals are housed under barrier-sustained conditions with controlled temperature (22° C), humidity, and lighting. They are kept in autoclaved polystyrene cages with stainless steel lids covered with individual Fiberglas filter tops, fed with standard laboratory chow, and given acidified water (0.001 N HCl) adlibitum. The food, water, and bedding for these animals is vacuum sterilized in a bulk sterilizer chamber vacuum cycle in an AMSCO automatic sterilizer adapted with a vacuum pump. Anesthetized animals are exposed to various traumatic insults, which subsequently result in gut mucosal injury. After specific time periods, the animals are sacrificed and the degree of bacterial translocation is determined by culturing the MLN and other organs, such as the spleen, liver, lung, and kidney, as well as the portal and systemic blood. The materials required in this model include anesthetic agent, Oster animal hair clipper, skin disinfectant, scissors, fine-tipped and curved forceps, polyethylene tubing, suture material, blood pressure recording device, syringes and needles, and burn template. Mice are anesthetized with an intraperitoneal (i.p.) injection of thiopental sodium and additionally, 50 mg/kg of either pentobarbital sodium or ketamine plus xylazine can be used. Rats are also anesthetized with an i.p. injection of either pentobarbital sodium or ketamine plus xylazine. Complete anesthesia ensues in approximately 5 minutes and lasts between 30 minutes and 1 hour.