Oestrogens are responsible for the sexual dimorphism in adult mice lung tissue, and this difference is most notable at sexual maturity. Oestrogen receptor-alpha (ERα) and the oestrogen receptor-beta (ERβ) are the two receptors that mediate oestrogen action, but adult mice lung tissue only expresses ERβ, and it is probably through this receptor that oestrogens exert their action. The goal of our study was to detect the expression of ERα and ERβ in mouse foetal lung tissues and identify possible gender differences. The foetal lung tissue was collected between developmental days E15-E19, processed for histology and the expression of oestrogen receptors was detected by immunohistochemistry. Over the 5 days of lung development that were evaluated ERα was not expressed in the foetal lung tissues of neither male nor female mice. In contrast, ERβ was detected in both sexes, although the immunoreactivity differed for each developmental day whilst the staining intensity observed for ERβ also indicated differences between male and female lung tissues. The results demonstrate the existence of a gender difference in the foetal expression of ERβ in lungs of mice.

In this work, we evaluate the lung retinoids content to study the possible difference between male and female mice during prenatal development and to comprehend if the vitamin A metabolism is similar in both genders. The study occurred between developmental days E15 and E19, and the retinol and retinyl palmitate lung contents were determined by HPLC analysis. We established two main groups: the control, consisting of foetuses obtained from pregnant females without any manipulation, and vitamin A, composed of foetuses from pregnant females submitted to vitamin A administration on developmental day E14. Each of these groups was subdivided by gender, establishing the four final groups. In the lung of control group, retinol was undetected in both genders and retinyl palmitate levels exhibited a sexual dimorphism. In the vitamin A group, we detected retinol and retinyl palmitate in both genders, and we observed a more evident sexual dimorphism for both retinoids. Our study also indicates that, from developmental day E15 to E19, there is an increase in the retinoids content in foetal lung and a gender difference in the retinoids metabolism. In conclusion, there is a sexual dimorphism in the lung retinoids content and in its metabolism during mice development.

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This study analyzes an experimental model for the study of reactions from gastric tissue exposed to enteric environment. Morphological studies were performed by histological, histochemical and immunohistochemical methods, using formalin-fixed biopsies of full-wall-thickness gastric implants in a whole-wall jejunal defect. These grafts suffered severe lesions, characterized by chronic atrophic gastritis, foveolar hyperplasia, glandular cystic transformation, and intestinal metaplasia. Increase in acidic mucins was also observed. There was no proliferating cell nuclear antigen (PCNA) overexpression. The results suggest that this model can be useful to investigate the heterotopic grastropathy and can be applied in further research studies.

We determined retinoids liver content in male and female mice fetuses to study a possible sex difference during prenatal development, and to ascertain if vitamin A metabolism is similar in both sexes. The study was performed between developmental days E15-E19, and the fetuses were collected from two main groups: control (no manipulation) and vitamin A (administration of vitamin A on developmental day E14). Each group was subdivided by sex and retinoids were analyzed by high performance liquid chromatography (HPLC). The control group did not have any retinol in the liver of both sexes. Fetuses from the vitamin A group began to accumulate retinol on day E16, until E19 and sexual dimorphism was exhibited. Retinyl palmitate content in the control group showed sexual dimorphism on some developmental days, and in the vitamin A group these differences were more significant. In conclusion, our study showed sexual dimorphism in the retinoids liver content during mice development and evidences a sex difference in vitamin A metabolism, with different capacities to store and metabolize retinoids.