Mechanisms of changes to the liver pigmentary component during the annual cycle (activity and hibernation) of Rana esculenta L
| Autor: | Carla Fenoglio, Rita Vaccarone, Franco Bernini, Annunzia Fraschini, Vittorio Bertone, Sergio Barni |
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| Rok vydání: | 2002 |
| Předmět: |
Male
Hibernation medicine.medical_specialty Histology Population Apoptosis Cell Count Biology Rana Melanin Internal medicine medicine Animals education Molecular Biology Ecology Evolution Behavior and Systematics Melanosome Melanins Analysis of Variance education.field_of_study TUNEL assay Cell growth Macrophages Rana esculenta Original Articles Cell Biology Immunohistochemistry Endocrinology Liver sense organs Anatomy Cell Division Developmental Biology |
| Zdroj: | Journal of Anatomy. 200:185-194 |
| ISSN: | 1469-7580 0021-8782 |
| Popis: | The present study was performed to elucidate the mechanisms responsible for the changes of melanin content/ distribution we had previously discovered in the liver parenchyma of Rana esculenta during natural hibernation. Melanomacrophagic component response was analysed using morphocytochemical methods. The results demonstrated that during the prehibernation period (October-November) the melanomacrophages reach the highest proliferative activity (BrdU, PCNA labelling) which is accompanied by an evident melanosynthesis (dopa-oxidase activity). In contrast, after hibernation, the decrease of liver pigmentation was the consequence of a partial cell loss by apoptotic mechanisms (TUNEL labelling, pyknosis-karyorhexis) accompanied by a decrease of melanosome content by autophagy and low melanosynthetic activity. On the basis of these findings, there is evidence that liver melanomacrophages represent a metabolically (melanin synthesis/degradation) and cytokinetically (proliferation/ death) active cell population during the annual cycle of the frog. The results are also discussed in relation to the functional synergism between hepatocytes and pigment cells in the adaptation to environmental changes. |
| Databáze: | OpenAIRE |
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