Effects of Depilatory Cream Formulation and Contact Time on Mouse Skin.

Depilatory creams are widely used in research to remove hair in preparation for surgery, imaging, and other procedures. However, few studies have evaluated the effects of these creams on mouse skin. We sought to determine the cutaneous effects of 2 different depilatory formulations of a widely used brand as related to the duration of exposure. We compared a standard body formula [BF] and a facial formula [FF] that is marketed as being more gentle on skin. The cream was applied to one flank for 15, 30, 60, or 120 s; hair on the contralateral flank was clipped and used as a control. Treatment and control skin were scored for gross lesions (erythema, ulceration, and edema), degree of depilation, and histopathologic changes. C57BL/6J (B6) and Crl:CD-1(ICR) (CD-1) mice were used to allow comparison of an inbred/pigmented strain to an outbred/albino strain. BF caused significant cutaneous injury to both strains of mice, whereas FF produced significant cutaneous injury only in CD-1 mice. Both strains showed gross skin erythema, with the most severe erythema seen in CD-1 mice treated with BF. Contact time did not affect histopathologic changes or gross erythema. Both formulations produced depilation comparable to clipping in both strains when left on for a sufficient duration. In CD-1, mice, BF required at least 15 s of exposure, whereas FF required at least 120 s. In B6 mice, BF required at least 30 s of exposure, whereas FF required at least 120 s. The 2 mouse strains did not show statistically significant differences in erythema or histopathologic lesions. Overall, these depilatory creams were comparable to clippers for hair removal from mice but they produce cutaneous injury that may affect research outcomes.

Evaluation of Nutritional Gel Supplementation in C57BL/6J Mice Infected with Mouse-Adapted Influenza A/PR/8/34 Virus.

Mice are a common animal model for the study of influenza virus A (IAV). IAV infection causes weight loss due to anorexia and dehydration, which can result in early removal of mice from a study when they reach a humane endpoint. To reduce the number of mice prematurely removed from an experiment, we assessed nutritional gel (NG) supplementation as a support strategy for mice infected with mouse-adapted Influenza A/Puerto Rico/8/34 (A/PR/8/34; H1N1) virus. We hypothesized that, compared with the standard of care (SOC), supplementation with NG would reduce weight loss and increase survival in mice infected with IAV without impacting the initial immune response to infection. To assess the effects of NG, male and female C57BL/6J mice were infected with IAV at low, intermediate, or high doses. When compared with SOC, mice given NG showed a significant decrease in the maximal percent weight loss at all viral doses in males and at the intermediate dose for females. Mice supplemented with NG had no deaths for either sex at the intermediate dose and a significant increase in survival in males at the high viral dose. Supplementation with NG did not alter the viral titer or the pulmonary recruitment of immune cells as measured by cell counts and flow cytometry of cells recovered in bronchoalveolar lavage (BAL) fluid in either sex. However, mice given NG had a significant reduction in IL6 and TNFα in BAL fluid and no significant differences in CCL2, IL4, IL10, CXCL1, CXCL2, and VEGF. The results of this study show that as compared with infected SOC mice, infected mice supplemented with NG have reduced weight loss and increased survival, with males showing a greater benefit. These results suggest that NG should be considered as a support strategy and indicate that sex is an important biologic variable in mice infected with IAV.