Ovarian Aging: Melatonin Regulation of the Cytometric and Endocrine Evolutive Pattern
Blanca E. Fernandez,
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.
Keywords: Aging, cell cycle, estradiol, melatonin, oocytes, ovarian aging, ovarian aging, ovary.
Rights & PermissionsPrintExport