Cyclic variation of the oviduct structure of Boulengerula taitana, an oviparous species of Gymnophiona: morphological changes, proliferation and apoptosis

Functioning of the amphibian oviduct is the subject of many studies, but detailed understanding of caecilian reproduction exists for very few species. In this study, a description is made of morphological changes of the oviduct of the caecilian Boulengerula taitana throughout the year, using conventional histology and immunohistochemistry. The reproductive cycle of this little-known species, originating from the Taita Hills in southeast Kenya, is annual. During the reproductive period (November–February), both lamina propria and the epithelium of the oviduct exhibit a maximum degree of development. The epithelial mucosa is more secretory and the cilia cells are abundant. Histological analysis shows the distribution of the different type of cells according to a specific pattern in the pars recta, pars convoluta and pars utera. Evaluation of proliferative (Ki-67 positive cells) and apoptotic cells (TUNEL and Apostain assays) into the different tissues brings out cyclic modifications of the lamina propria and epithelial cells throughout a seasonal cycle. The results demonstrate that the balance between cell proliferation and apoptosis reflects the functionality of the oviduct during the sexual cycle

Annual variation of ovarian structures of Boulengerula taitana (Loveridge 1935), a Kenyan caecilian

The Kenyan caecilian, Boulengerula taitanus inhabits a climate characterised by two distinct dry and wet seasons, and a single thermal minimum in June. It is oviparous with direct development and a remarkable dermatophagous maternal care, but the female reproductive cycle until now remains unknown. The purpose of this work was to complete the knowledge about the reproductive modes of this species, using anatomical and histological studies of the ovaries. Quantitative variations of follicle categories showed a continuous folliculogenesis. Yet, young corpora lutea were only detected between November and February during the short rain season and the short dry season, indicating ovulation occurred during these four months during the thermal maximum. Oestrogen and progesterone detection allowed determination of three reproductive periods during the year: preparation in September and October, ovulation from November until February and quiescence from March until August. So, the female reproductive cycle of B. taitanus appears to be annual and synchronised with testicular evolution. Because the ovulation was observed following the second peak of follicle production (beginning of June), temperature is supposed to be the main regulating factor of reproductive pattern in this caecilian

Targeting the human βc Receptor inhibits contact dermatitis in a transgenic mouse model

Allergic contact dermatitis (ACD) is a prevalent and poorly controlled inflammatory disease caused by skin infiltration of T cells and granulocytes. The beta common (bc) cytokines GM-CSF, IL-3, and IL-5 are powerful regulators of granulocyte function that signal through their common receptor subunit bc, a property that has made bc an attractive target to simultaneously inhibit these cytokines. However, the species specificity of bc has precluded testing of inhibitors of human bc in mouse models. To overcome this problem, we developed a human bc receptor transgenic mouse strain with a hematopoietic cell‒specific expression of human bc instead of mouse bc. Human bc receptor transgenic cells responded to mouse GM-CSF and IL-5 but not to IL-3 in vitro and developed tissue pathology and cellular inflammation comparable with those in wild-type mice in a model of ACD. Similarly, Il3e/e mice developed ACD pathology comparable with that of wild-type mice. Importantly, the blocking antiehuman bc antibody CSL311 strongly suppressed ear pinna thickening and histopathological changes typical of ACD and reduced accumulation of neutrophils, mast cells, and eosinophils in the skin. These results show that GM-CSF and IL-5 but not IL-3 are major mediators of ACD and define the human bc receptor transgenic mouse as a unique platform to test the inhibitors of bc in vivo.Kwok Ho Yip ... Barbara J. McClure ... Angel F. Lopez ... Harshita Pant ... Hayley S. Ramshaw ... et. a