Histopathology of mammary glands of rats fed different diets and challenged with different stimulus. Hematoxylin and eosin stained slides were made with mammary tissues collected from rats fed the SO diet (B) or FO diet (C) and challenged with saline or LPS. PMN prevalence (A) in alveoli was estimated by using light microscopic (Olympus BH2, Japan) analysis at a magnification of 400×. Statistics are shown as means ± SE. Statistics with no common letters differ significantly (P < 0.05).