Fig. 1

Histopathological analysis of mouse gut and mammary tissues after microbiota transplantation. A Pathological changes in mammary gland surface, where different abdominal mammary glands were found as swollen and red in the mastitis (CM) group of mice on Day 27 after FMT (fecal microbiota transplantion) and MMT (milk microbiota transplantion). Mammary glands of mouse are highlighted by red circles. B Representative photomicrographs of mammary epithelial tissue after haematoxylin and eosin staining (×100 magnification). The lesion in the mammary epithelial cells is characterised by a central area of necrosis, broken lobules, damaged acinuses and destroyed epithelial cells, with with large numbers of inflammatory cells, predominantly neutrophils (dark bluish) and macrophages (red) (yellow arrows), in the mammary lobule, supporting connective tissue and linning of the epithelium. C Representative photomicrographs of colon (crypts, lamina propria, muscularis mucosae and submucosa) tissue after haematoxylin and eosin staining (×100 magnification). Histopatholaogical changes in the colon tissue include moderate to severe inflammatory cell infiltration into mucosa and submucosa, disorder in mucosal structure: epithelial necrosis, extension of the subepithelial space, and structural damage of villi (yellow arrows). Scale bars: 100 μm and 50 μm. D The tissue injury scores in the mammary gland and colon. The X-axis represents the groups of samples (CM and H) while the Y-axis denotes the injury scores as measured through Chiu Scoring System (×100 magnification)