Animals

Three-month old C57Bl/6J mice were used to test the effects of gut-derived LPS on anxiety-like and repetitive behaviors. For experiment 1, 14 male wild-type (C57Bl/6J) mice and 8 male Tlr4−/− (Tlr4^lps-del on C57Bl/6 background) mice were randomly selected from a colony bred in-house. Founder mice for this colony were sourced from Jackson Labs (Bar Harbor, ME). As this colony contained a negligible number of females, female subjects were not used in this experiment. For experiment 2, 64 male and 64 female C57Bl/6J mice were purchased at 10 weeks of age (Jackson Labs) and housed in our facility for 2 weeks prior to the study. For both experiments, all subjects were housed in same-sex pairs prior to the beginning of the study. The mice were housed in a room maintained in a 12:12 light-dark cycle, at 68–72 °F and approximately 50% humidity, and were fed ProLab 5001 diet ad libitum (LabDiet, St. Louis, MO). All experimental protocols were approved by the Institutional Animal Care and Use Committee at Georgia State University and were performed in accordance with the National Institutes of Health Guidelines for the Care and Use of Laboratory Animals. All procedures were designed to minimize subject discomfort and use the fewest animals necessary for statistical analysis.