Corticotropin-releasing hormone-receptor 1 (CRH-R1) and CRH-binding protein (CRH-BP) are expressed in the gills and skin of common carp Cyprinus carpio L. and respond to acute stress and infection

Contains fulltext : 35966.pdf (publisher's version ) (Open Access)We established that corticotropin-releasing hormone (CRH), CRH-binding protein (CRH-BP) and CRH-receptor 1 (CRH-R1) are expressed in the gills and skin of common carp Cyprinus carpio, an early vertebrate. Immunoreactive CRH was detected in macrophage-like cells in gills and skin, in fibroblasts in the skin and in endothelial cells in the gills. The involvement of the CRH system in gills and skin was investigated in response to infection and in an acute restraint stress paradigm. Carp were infected with the protozoan leech-transmitted blood flagellate Trypanoplasma borreli and subjected to acute restraint stress by netting for 24 h. The expression of CRH-BP and CRH-R1 genes in the gills and in the skin is downregulated after both infection and restraint. Thus the peripheral CRH system reacts to infection and stress. The gills and skin separate the internal from the external environment and are permanently exposed to stress and pathogens. Because of their pivotal role in maintaining the homeostatic equilibrium, these organs must act locally to respond to diverse stresses. Clearly, the CRH system is involved in the response of the integument to diverse stresses at the vulnerable interface of the internal and external milieu

Opercular epithelial cells: A simple approach for in vitro studies of cellular responses in fish

Contains fulltext : 35264.pdf (publisher's version ) (Closed access)This study evaluated the efficacy of fish opercular external (skin) and inner (opercular membrane) epithelium as an in vitro model for toxic and other substances studies. The rainbow trout (Oncorhynchus mykiss) operculum was cultured in 12-well dishes containing sterile Leibovitz 15 (L-15) supplemented with glutamine medium during 24 h at 9 ◦C, and the effect of copper, a toxic agent, and/or cortisol, an endogenous agent, on the epithelial cells was analyzed using light microscopy techniques. The opercula were submitted to four treatments: (i) control (Cont), L-15 medium only, (ii) 0.28 _Mcortisol (Cort), (iii) 100 _MCuSO4 (Cu), and (iv) 0.28 _M cortisol + 100 _M CuSO4 (Cort–Cu). The tissue condition after 24 h incubation was analyzed by staining the mucous cells for neutral and acid mucosubstances. Cellular necrosis was evaluated by measuring the lactate dehydrogenase (LDH) leakage at 12 and 24 h incubation. Cellular proliferation, apoptosis, metallothionein (MT) and glucocorticoid receptor (GR) expression were evaluated by immunohistochemistry. TheLDHleakagewas higher and the proliferating cell nuclear antigen (PCNA) positive-stained cells were lower in Cu treatment in both, epidermis and opercular membrane. Apoptotic cells in the opercular membrane were higher in the Cort and Cort–Cu treatments while, in the epidermis, they were higher in Cu and Cort–Cu treatments. GR-positive stained cells decreased significantly in all treatments in both epithelia and the MT-positive cells increased in the Cu and Cort–Cu treated groups. Copper showed to be a potent toxic stressor killing the cells via necrosis, decreasing the number of PCNA-positive cells and inducing MT synthesis while cortisol did not affect the MT synthesis, although it might stimulate apoptosis. The results are evidence that the opercular epithelia serve as a suitable model for studying in vitro effects of toxic agents, as well as endogenous factors on the cellular responses without interference of the physiological state of fish being useful to predict in vivo toxicity

A short-term in vitro gill culture system to study the effects of toxic (copper) and non-toxic (cortisol) stressors on the rainbow trout, Oncorhynchus mykiss (Walbaum)

Contains fulltext : 13848.pdf (publisher's version ) (Closed access

Corticosteroid receptors involved in stress regulation in common carp, Cyprinus carpio

Contains fulltext : 72105.pdf (publisher's version ) (Open Access)15 p

The first appearance of Rodlet cells in carp (Cyprinus carpio L.) ontogeny and their possible roles during stress and parasite infection

Item does not contain fulltextThe origin and function of rodlet cells (RCs) are still a matter of discussion. Whereas the exogenous hypothesis considers them parasites, the endogenous hypothesis regards them as a genuine fish cell population with a secretory and/or leukocyte function. In order to shed more light on these questions we focused on the location and appearance of RCs during carp (Cyprinus carpio) ontogeny. Typical RCs were seen at 5days post fertilisation (dpf) between kidney and intestine, at 6dpf in the intestine and at 8dpf in both anterior and posterior kidney and in the abdominal cavity among the mesothelial cells. The RC number increased with age and after 14dpf they were also present in gills. The early appearance of the RCs during carp ontogeny support the endogenous hypothesis stating that RCs are genuine constituents of fish tissue and suggest that they are 'immune cells'. The fact that the RCs of the gills secrete their content into the surrounding water, combined with the strategic location around blood vessels in kidney and within intestinal epithelium, would also support an important role in host defense. To investigate whether RC numbers in gills and kidney are related to typical fluctuations in the physiology during stress and infection we counted their number in gills and kidney after parasite infection and stress. In the gills the number of RCs increased after infection but did not change after stress while in the kidney their number increased after stress and no significant changes were observed after infection

Regulation of the stress response in early vertebrates

Contains fulltext : 32920.pdf (publisher's version ) (Closed access)The acute stress response is a key regulatory system for the maintenance of homeostatic equilibrium that is activated upon an imminent or ongoing disturbance of the "milieu interieur". In general, the stress response in bony fish is similar to that of mammals. The recent cloning and characterization of corticotropin-releasing hormone-binding protein (CRH-BP) in carp (Cyprinus carpio L.) reflects the conservation of the CRH signaling system throughout vertebrates. Now, we can start to investigate the processes that are mediated by the factors that make up this system. The stress response is only one of these processes

Alterações histológicas em brânquias de tilápia nilotica Oreochromis niloticus causadas pelo cádmio Histological alterations in gills of Nile tilapia Oreochromis niloticus caused by cadmium

Os efeitos histopatológicos do cádmio nas brânquias de tilápia Oreochromis niloticus foram estudados por microscopia óptica, usando 25mgl-1 de CdCl2 durante quatro dias, com o objetivo de identificar seus efeitos agudos na estrutura das brânquias. A morfologia geral das brânquias de O. niloticus é idêntica à de outros teleósteos, apresentando quatro pares de arcos branquiais com filamentos bem desenvolvidos. Situadas lateralmente, encontram-se as lamelas provenientes do eixo central dos filamentos. No epitélio filamentar foi possível identificar células de cloro, pavimentosas e mucosas. Os peixes expostos ao cádmio mostraram sinais de lesões epiteliais; edema intersticial, vasodilatação das lamelas, destacamento do epitélio lamelar e proliferação do epitélio filamentar. As alterações observadas também incluíram fusão nas lamelas como resultado de hiperplasia e hipertrofia epitelial, ruptura do sistema de células pilar, aneurismas e necroses.<br>The histopathogical effects of cadmium on the gills of tilapia Oreochromis niloticus were studied by light microscopy, using 25mgl-1 of CdCl2 during four days to identified the effects of short-term exposure on gills structure. The general morphology of O. niloticus gills is similar to the other teleostean fishes, showing four pairs of gills arches with well developed filaments. Bilaterally situated, secondary lamellae branches are found from the central axis of the filaments. The filamentar epithelium showed the chloride cells, the pavement cells and mucous cells. Fish exposed to cadmium showed signs of epithelial lesion, namely the interstitial edema, swollen of the lamellae, lifting and cellular proliferation of the filamentar epithelium. The changes of the gills also included lamellar fusion as a result of epithelial hyperplasia and hypertrophy, the breakdown of pillar cell system, and aneurisms with some ruptures and necrosis, especially in the filamentar epithelium