Fig. 2.

A: histological changes of the mammary gland of rats at day 49 after a full-term pregnancy (P) or exogenous hormone treatment (H) compared with the control (C) rats (scale bars = 100 μm). Each photomicrograph was randomly selected from an individual animal within the group. B: histological analyses of a mammary gland section using the free-hand area-of-interest (AOI) tool of Image Pro Plus for the areas of parenchyma (ii) or the areas of both parenchymal and stromal tissues (iii). i, The section of ii and iii without using the AOI tool.