A Reproducible Scoring System for Quantification of Histologic Lesions of Inflammatory Disease in Mouse Gastric Epithelium

Comparison of experimental groups by microscopic examination is a common and useful method for evaluating animal models of disease. Quantification of lesions is challenging, however, and differences in scoring systems hinder comparison of results from different laboratories. The purpose of this study was to validate a simple and reproducible scoring system for Helicobacter pylori-associated gastric disease in mice. The system is based on quantification of the percentage of microscopic fields in which lesions are present, rather than on subjective estimates of lesion severity. Linear regression analyses revealed good agreement between investigators in scoring of all 3 histologic criteria examined. The range of correlation coefficients between individual readers' scores and mean scores for the 3 histologic criteria examined were: neutrophilic inflammation, 0.845 to 0.935; gastritis sufficient to displace glands, 0.919 to 0.943; and epithelial metaplasia, 0.650 to 0.799. Comparison of scores in different experimental groups by analysis of variance and Fisher least significant difference tests revealed significant differences between infected and uninfected groups and between immunodeficient and immunocompetent groups. We propose that this system may be useful in standardizing the morphologic evaluation of rodent models of H. pylori and that a similar system could be devised for evaluation of other animal models of enteric disease.