title: Apoptosis in thymus of teleost fish.
abstract: The presence and distribution of apoptotic cells during thymus development and in adult were studied by in situ end-labelling of fragmented DNA in three temperate species carp (Cyprinus carpio), sea bass (Dicentrarchus labrax) and dusky grouper (Epinephelus marginatus) and in the adult thymus of three Antarctic species belonging to the genus Trematomus spp. During thymus development some few isolated apoptotic cell (AC) firstly appeared in the central-external part of the organ (carp: 5 days ph; sea bass: 35 days ph grouper: 43 days ph). Initially the cells were isolated and then increased in number and aggregated in small groups in the outer-cortical region of the thymus larvae. The high density of apoptotic cells was observed in the junction between cortex and medulla from its appearance (border between cortex and medulla, BCM). ACs decreased in number in juveniles and adult as well as the ACs average diameter. In late juveniles and in adulthood, the apoptosis were restricted to the cortex. In Antarctic species the thymus is highly adapted to low temperature (high vascularisation to effort the circulation of glycoproteins enriched plasma and strongly compact parenchyma). The apoptosis process was more extended (4-7 fold) as compare with the thymus of temperate species, even if the distribution of ACs was similar in all examined species. Data suggested a common process of T lymphocyte negative-selection in BCM of thymus during the ontogeny. The selection process seems to be still active in adult polar fish, but restricted mainly in the cortex zone.
authors: Department of Ecology and Biology, Tuscia University, Viterbo, Italy. nromano@unitus.it
authors: Nicla
authors: N
authors: Romano
authors: Giuseppina
authors: G
authors: Ceccarelli
authors: Cecilia
authors: C
authors: Caprera
authors: Elisabetta
authors: E
authors: Caccia
authors: Maria Rosaria
authors: MR
authors: Baldassini
authors: Giovanna
authors: G
authors: Marino
mesh_terms: D000818:Animals; D000864:Antarctic Regions; D017209:Apoptosis; D003531:Cypriniformes / Q000254:growth & development / Q000502:physiology*; D053938:DNA Fragmentation; D004777:Environment; D005821:Genetic Techniques; D007814:Larva / Q000254:growth & development / Q000502:physiology; D010473:Perciformes / Q000254:growth & development / Q000502:physiology*; D013045:Species Specificity; D013950:Thymus Gland / Q000502:physiology*
keywords: Antarctic fish; Apoptosis; Fish; Thymus; Thymus ontogeny