The African catfish Clarias gariepinus was used as a model for wound healing and tissue regeneration in a scale-less fish. A temporal framework of histological and cell proliferation markers was established after wound induction in the dorsolateral cranial region, by removing the epidermal and dermal layers, including stratum adiposum (SA). Wound closure and epidermis formation was initiated within 3 h post-procedure (hpp) with migration and concomitant proliferation of epidermal cells from the wound borders. The wound was covered by this primary epidermal front 12 hpp and fusion of the opposing epidermal fronts occurred within 24 hpp. Attachment of the newly formed epidermal layer to the underlying dermis was observed 48 hpp concomitant with a second wave of cell proliferation at the wound edge. Normal epidermal thickness within the wound was achieved 72 hpp. Formation of a basement membrane occurred by 120 hpp with concomitant emergence of the SA from the wound borders. Wound healing in C. gariepinus skin involved closure of the wound and re-epithelization through cell migration with a single wave of early cell proliferation not documented in other species. Furthermore, covering of the wound by epithelium as well as the reappearance of the basement membrane and SA occurred sooner than in other fish species.

The skin histology of Clarias gariepinus, a scaleless teleost from south central Africa, is described. The African catfish epidermis is composed of epithelial cells representing 62.3% of volumetric density (Vv), club cells (Vv = 25.7%), mucous cells (Vv = 10.5%) and melanocytes (Vv = 1.4%). Its thickness amounts to approximately 240 microm. The dermis is distinguished by two well differentiated layers, the stratum adiposum, containing prominent amounts of adipose tissue, which forms large, oblong compartments circumscribed by dense connective tissue, and the stratum compactum, which is rich in compacted collagen fibres. Compared with other catfish species the dermis thickness is considerably thicker ranging from 1.3 to 2.3 mm. The function of this type of skin is discussed.

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In cattle, the oviduct plays a major role in the reproductive process; however, molecular control of oviduct receptivity to the embryo is poorly understood. A model for receptivity based on size of the pre-ovulatory follicle (POF) was used to compare oviductal morphology, cellular proliferation, and candidate transcript abundance. Growth of the POF of Nelore (Bos indicus) cows was manipulated to produce two groups: a large POF-large corpus luteum (CL) group (LF-LCL; greater receptivity) and a small POF-small CL group (SF-SCL). Samples of the ampulla and isthmus ipsilateral and contralateral to CL were collected 4 days after GnRH-induced ovulation. Tissues were either embedded in paraffin for Harris-Hematoxylin and Eosin and periodic acid-Schiff staining and KI67 immunostaining, followed by morphological analyses, or stored at -80 °C for RNA extraction, cDNA synthesis, and qPCR analyses. The effects of group (LF-LCL and SF-SCL), region (ampulla and isthmus), and side (ipsilateral and contralateral) were analyzed using three-way nested ANOVA. The ipsilateral ampulla of the LF-LCL group presented more primary mucosal folds, a greater mucosal-folding grade and luminal perimeter, and more secretory cells and proliferating cells when compared with the ampulla of the SF-SCL group and with the contralateral ampulla of both groups. There were no morphological differences in the isthmus between groups and sides. Changes in transcript abundance are suggestive of LF-LCL-stimulated secretory activity. In summary, ovulation of a larger POF generates a periovulatory endocrine milieu that modulates morphological and functional features of the bovine oviduct which may support embryo survival and development.

Background: Approximately 30% of all breast tumors do not express estrogen receptor (ER) and patients with these tumors present poor prognosis and respond poorly to hormone therapy. Calcitriol through its vitamin D receptor (VDR) exerts antiproliferative, apoptotic and pro-differentiating effects in cancer. Calcitriols effects upon ER expression in breast cancer cells is controversial. Therefore, in order to clarify this issue, the aim of the present study was to determine if calcitriol induces ERα expression in ERα-negative breast cancer cells and could restore antiestrogen responses. The evaluation of calcitriol effects was performed in terms of proliferation and regulation of the following genes: Cyclin D1, involved in cell cycle, and Ether-à-go-go 1 (Eag1), related to cell proliferation and tumor progression. Methods: Cultured cells derived from ERα-negative breast tumors and an established ERα-negative breast cancer cell line (SUM 229) were used in this study. These cells were treated with calcitriol and reverse transcription-PCR or western blotting analyses were performed to assess ERα expression. Growth assays with XTT were used to evaluate the antiproliferative response to the antiestrogens fulvestran and tamoxifen. Gene expression analysis for Cyclin D1 and Eag1 was evaluated by real time PCR in cells treated simultaneously with calcitriol plus estradiol or fulvestran. Results: The treatment with calcitriol in ER-negative breast cancer cells resulted in the induction of ERα. This effect was specifically mediated through the vitamin D3 receptor (VDR), since the VDR antagonist TEI-9647 effectively inhibited the ability of calcitriol to stimulate ERα gene expression. Consequently, the induction of ERα by calcitriol restores the response to antiestrogens in breast cancer cells by inhibiting cell proliferation. Co-treatment of calcitriol and antiestrogens down-regulated Cyclin D1 and Eag1 gene expression. Conclusion: Calcitriol induced the expression of ERα and restored antiestrogenic responses in ERα-negative breast cancer cells. Moreover, fulvestran down regulated mRNA expression of Cyclin D1 and Eag1 when ERα-negative cells were pre-treated with calcitriol. These results suggest that the combined treatment with calcitriol and antiestrogens could be a new therapeutic strategy for ERα-negative breast cancer patients. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-29.