title: Ovarian aging: melatonin regulation of the cytometric and endocrine evolutive pattern.
abstract: We have investigated the effect of melatonin administration on the cytometric and endocrine functions of the ovary during aging. Young cyclic (3 months old), middle-aged pre-acyclic (13 months old), and old acyclic (22 months old) female Wistar rats were used for two months, in both control and melatonin-treated groups. Cell cycle by flow cytometry: the percentage of ovarian cells in the G0-G1 phase was the highest in both control and melatonin-treated rats. However, melatonin treatment significantly reduced (P< 0.05) the percentage of cells in the G0-G1 phase compared to control rats. This reduction of cells in the G0-G1 phase is derived to the S phase in cyclic and acyclic rats. The possibility that a tumoral process leads to a proliferative effect observed in young and acyclic melatonin-treated rats was ruled out because no significant differences were found for p53 and Ki67 expression levels between control and melatonin groups. Density of oocytes: the oocyte number per ovary unit volume was not affected by melatonin treatment in the three age ranges studied. Melatonin treatment in middle-aged (pre-acyclic) rats resulted in significantly higher (P< 0.05) ovarian volume; higher oocyte volume, without significant differences, and oocytes in circular form were significantly (P< 0.05) higher than in control rats. Melatonin treatment during pre-acyclic age range could resynchronize the estrous cycle periodicity. Melatonin treatment was able to maintain the same levels of estradiol in the pre-acyclic age groups studied as those observed in the young cyclic rats. The present results indicate that melatonin administration to middle-aged female rats produces beneficial effects that extend the reproductive function of the ovary.
authors.affiliation: Departamento de Biología Funcional, Área de Fisiología, Facultad de Medicina, Universidad de Oviedo, Oviedo, Asturias, Spain. beatrizd@uniovi.es
authors.forename: Blanca E
authors.initials: BE
authors.lastname: Fernández
authors.forename: Elena
authors.initials: E
authors.lastname: Díaz
authors.forename: Carmen
authors.initials: C
authors.lastname: Fernández
authors.forename: Paula
authors.initials: P
authors.lastname: Núñez
authors.forename: Beatriz
authors.initials: B
authors.lastname: Díaz
mesh_terms: D000375:Aging / Q000473:pathology / Q000502:physiology*; D000818:Animals; D002452:Cell Count; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D004958:Estradiol / Q000097:blood; D004971:Estrus / Q000187:drug effects / Q000502:physiology; D005260:Female; D005434:Flow Cytometry; D019394:Ki-67 Antigen / Q000378:metabolism; D008550:Melatonin / Q000494:pharmacology / Q000502:physiology*; D009865:Oocytes / Q000166:cytology / Q000187:drug effects; D010053:Ovary / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012098:Reproduction / Q000187:drug effects / Q000502:physiology; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D019394:Ki-67 Antigen; D016159:Tumor Suppressor Protein p53; D004958:Estradiol; D008550:Melatonin