Healing of corneal epithelial wounds in marine and freshwater fish

Healing and mucosal immunity in the skin of experimentally wounded gilthead seabream (Sparus aurata L)

Skin lesions are very common in fisheries, increasing the risk of pathogens entering through the wounded skin of the fish. In the present assay, the progression of wound healing was studied over a 7 day period in gilthead seabream (Sparus aurata L.) after making experimental wounds in two different locations: above (group A) or below (group B) the lateral line. Macroscopic observation confirmed faster wound healing of the wounds of fish from group B. Furthermore, several immune-related components were studied in the skin mucus of wounded fish to ascertain whether wounding altered the mucus composition compared with the values obtained from non-wounded fish (group C, control). Significant variations were detected depending on both the site of the wound and the studied parameter. At the same time, the gene expression profile of several immune-relevant genes, including pro-inflammatory (il1b,il6, tnfa), anti-inflamamtory (tgfb, il10), immunoglobulins (ighm, ight), involved in oxidative stress (sod, cat) and in skin regeneration (krt1and grhl1) were studied in the three groups of fish (A, B and C). The results throw further light on the complex process of skin wound healing in fish, since substantial changes in the skin mucus and in the skin gene expression originated by the presence of wounds were observed. This work underline some important differences depending on the place of the fish body where the wound is located. Of particular note was the fact that such changes depended on the site of the wound.

Distribution of carnosine-like peptides in the nervous system of developing and adult zebrafish (Danio rerio) and embryonic effects of chronic carnosine exposure

Carnosine-like peptides (carnosine-LP) are a family of histidine derivatives that are present in the nervous system of various species and that exhibit antioxidant, anti-matrix-metalloproteinase, anti-excitotoxic, and free-radical scavenging properties. They are also neuroprotective in animal models of cerebral ischemia. Although the function of carnosine-LP is largely unknown, the hypothesis has been advanced that they play a role in the developing nervous system. Since the zebrafish is an excellent vertebrate model for studying development and disease, we have examined the distribution pattern of carnosine-LP in the adult and developing zebrafish. In the adult, immunoreactivity for carnosine-LP is specifically concentrated in sensory neurons and non-sensory cells of the olfactory epithelium, the olfactory nerve, and the olfactory bulb. Robust staining has also been observed in the retinal outer nuclear layer and the corneal epithelium. Developmental studies have revealed immunostaining for carnosine-LP as early as 18 h, 24 h, and 7 days post-fertilization in, respectively, the olfactory, corneal, and retinal primordia. These data suggest that carnosine-LP are involved in olfactory and visual function. We have also investigated the effects of chronic (7 days) exposure to carnosine on embryonic development and show that 0.01 microM to 10 mM concentrations of carnosine do not elicit significant deleterious effects. Conversely, treatment with 100 mM carnosine results in developmental delay and compromised larval survival. These results indicate that, at lower concentrations, exogenously administered carnosine can be used to explore the role of carnosine in development and developmental disorders of the nervous system.

Wound management in teleost fish: biology of the healing process, evaluation, and treatment

Wound healing, although similar to terrestrial vertebrates, occurs faster in fish species in a proper aquatic environment. Wound management must involve identification and correction of potential noninfectious and/or infectious causes of disease. Wound evaluation includes assessment of the wound as well as systematic examination of the patient, water quality conditions, and husbandry practices. Diagnostic evaluation should, at a minimum, include physical examination, skin/cornea (if indicated) scraping, and lesions cultures. The clinician should also consider full thickness wound biopsies, gill and fin biopsies, blood collection, and radiographs for systemic evaluation as well. Local wound management should follow basic principles of wound care including cleaning and lavage, debridement, primary closure if indicated, and local and/or systemic antiinfectives. Monofilament absorbable or nonabsorbable sutures are commonly used for primary closure of wounds. Diagnostic results, patient and client compliance, and economic impact should guide systemic methods of treatment for wound care. Options for systemic therapy include oral or gavage, parenteral, bath, or prolonged immersion treatments. With bath or prolonged immersion therapies, aquatic systems must be properly prepared for treatment. Treatment of identified pathogens, proper water quality and husbandry, supportive care and nutrition must all be provided to promote an ideal wound healing environment for the teleost fish.

Ophthalmic disease of fish

Ocular disorders in fish are common and can occur as primary or secondary manifestations of systemic disease. Because most fish are sight feeders, visual impairments usually have fatal consequences for the individual fish and can lead to substantial economic losses for the client. This article encourages practitioners to perform a complete ocular examination as part of routine physical examinations in fish by providing a review of the functional anatomy of the teleostean eye, clinical work-up, ocular examination, ocular diseases, and treatment.

Evidence for gelsolin as a corneal crystallin in zebrafish

We have shown that gelsolin is one of the most prevalent water-soluble proteins in the transparent cornea of zebrafish. There are also significant amounts of actin. In contrast to actin, gelsolin is barely detectable in other eye tissues (iris, lens, and remaining eye) of the zebrafish. Gelsolin cDNA hybridized intensely in Northern blots to RNA from the cornea but not from the lens, brain, or headless body. The deduced zebrafish gelsolin is approximately 60% identical to mammalian cytosolic gelsolin and has the characteristic six segmental repeats as well as the binding sites for actin, calcium, and phosphatidylinositides. In situ hybridization tests showed that gelsolin mRNA is concentrated in the zebrafish corneal epithelium. The zebrafish corneal epithelium stains very weakly with rhodamine-phalloidin, indicating little F-actin in the cytoplasm. In contrast, the mouse corneal epithelium contains relatively little gelsolin and stains intensely with rhodamine-phalloidin, as does the zebrafish extraocular muscle. We propose, by analogy with the diverse crystallins of the eye lens and with the putative enzyme-crystallins (aldehyde dehydrogenase class 3 and other enzymes) of the mammalian cornea, that gelsolin and actin-gelsolin complexes act as water-soluble crystallins in the zebrafish cornea and contribute to its optical properties.

Kinematics of epithelial wound closure in the rabbit cornea

The kinematics of wound closure in the healing rabbit corneal epithelium are modelled. The analysis is able to model the movement of the wound edge on the corneal surface. A unified formalism is described which embeds the surface velocity of the wound margin within the computational algorithm to enable calculation of the surface velocity of the wound margin from the time course of (1) planar wound area, or (2) wound diameter. The procedure can be implemented with the standard least-squares estimation procedure. A polynomial velocity function is discussed, but the model allows for any appropriate velocity function to be used to suit particular conditions of wound closure. Corneal curvature effects are incorporated to avoid the errors associated with a planar representation of wound closure on a curved corneal surface. The approach offers greater flexibility by avoiding the theoretical flaws of previous models which are often limited in scope and nonbiological in nature.

Specular microscopy of vertebrate corneal endothelium: a comparative study

Central corneal endothelia in a variety of lower- and higher vertebrate animals were photographed with a widefield specular microscope and analysed with either fixed-frame or computer-assisted morphometric analysis. The endothelium of the dogfish shark, an elasmobranch, contained 2300 cells mm-2 and demonstrated a very delicate irregular 'reversal pattern'. The goldfish, a teleost, had 432 cells mm-2 and displayed a jigsaw-puzzle-like pattern. The bullfrog, an amphibian, and the gecko, a reptile, had 550- and 481 cells mm-2, respectively, and a relatively uniform polygonal endothelial pattern similar to that observed in mammals. The goose, a bird, had a cell density of 2410 cells mm-2 with a uniform hexagonal pattern (79%) which was similar to mammalian (rat, 58-76%; rabbit, 71%; dog, 78%; human, 61-75%) hexagonal patterns. The findings on the endothelial appearance in these vertebrate animals suggest that a correlation exists between endothelial morphology, vertebrate phylogeny and their respective functional and structural capacity.