Effects of Chlorine on Gut Microbiota in the Mouse Models

Goals / Objectives
Gut microbiota is closely related to human health and disease through modulating metabolic functions of nutrient absorption, trophic effects on the intestinal epithelium, and protection against non-commensal microbes. The addition of chlorine to drinking water has been found to alter the enteric environment and therefore potentially affect the biology and distribution of the gut microbiota. This in turn could affect many aspects of human health. In special animal studies, the chlorine in drinking water has shown to affect tumorigenesis. Here we seek to study the broad effects of chlorine on gut microbiota health in the mouse models.

Project Methods
Mice strains C57BL/6J and BALB/cJ will be ordered from Jackson Laboratory. Two sets of breeder mice will be ordered for each strain, 8 mice in total. Upon receiving the mice, they and their offspring will be maintained using a chlorine free diet and chlorine free water. The chlorine free diet and chlorine free water are provided by the Primary Investigator. The chlorine free diet will be purchased from PMI international and the chlorine free water will be purchased from deer park. After quarantine, the breeders will be paired, resulting in the addition of 2 generations of mice. The mice bred for this experiment will be maintained by the PIâ¿¿s staff, and therefore these mice will not require cage maintenance or feed/water replenishment by ULAR staff. C57BL/6J and BALB/cJ mice bred will be maintained under chlorine free conditions for at least two generations. To begin the experiment, experimental cohorts of mice (60 mice) will be fed with water and food prepared with chlorine (water up to 5 mg/liter, food 5g/kg). The control group (12 mice) will be feed with in chlorine free diet and chlorine free water. Food will be purchased from PMI international and water will be deer park water with chlorine added. The mice will be monitored over the course of 4-8 weeks. Once a week, fecal pellets will be collected and blood will be harvested from mice using retro-orbital eye bleeding while under anesthetic effects of isoflurane. At the end of the experiment mice will be sacrificed using CO2 followed by cervical dislocation. Blood, tissue and organs will be harvested post euthanasia and subject to analysis. The following analyses will be carried on the sample collected. 1. Metabolic component analysis. a. Major metabolic components will be analyzed. This will include chlorine. 2. Microbiota metagenomic analysis a. Component of microbiota will be analyzed and compared. 3. Microbiota transcriptome analysis a. The gene expression profile of microbiota will be analyzed by Helicos single molecule sequence and analyzed. Follow up studies: Based on the results of the above study, a second study will be planned to avoid the potential loss microbiota caused by chlorine experiments. Additional additives may be add to the water and food to neutralize the effect of chlorine.