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Melatonin decreases mRNA for histone H4 in thymus of young rats
R M Sáinz1, J C Mayo, M Kotler
1Departamento de Morfología y Biología Celular, Universidad de Oviedo, Spain.
Abstract:
The antiproliferative properties of melatonin have been previously demonstrated for several normal and tumoral tissues. In a recent report we have shown that melatonin is able to inhibit programmed cell death in thymus both, in vivo and in vitro. Given that other authors have related programmed cell death and cell proliferation and that no previous reports on melatonin and cell division exist on thymus, we decide to study the possible antiproliferative effect of melatonin in this organ measured as the levels of mRNA for the histone H4. We found that melatonin inhibits cell division on thymus when administered chronically both, at high (500 microg/body weight) and low (50 microg/body weight) dose. We also found a circadian rhythm of the mRNA for histone H4, opposed to the one previously described for melatonin, supporting the negative regulation by this hormone of cell division on thymus. A single dose of melatonin (50 microg/body weight) was not able to decrease the levels of mRNA for H4 in the time-points studied but after two hours of its administration. Finally, we report the inhibitory effect of melatonin in the cell proliferation of Harderian gland, brain, lung and kidney.
Insights
Melatonin inhibits thymus cell division, as measured by histone H4 mRNA levels. This hormone also shows an antiproliferative effect on other organs, impacting cell proliferation.
Area of Science:
- Endocrinology
- Cell Biology
- Molecular Biology
Background:
- Melatonin exhibits antiproliferative properties in various tissues.
- Previous research demonstrated melatonin's inhibition of programmed cell death in the thymus.
- The relationship between programmed cell death and cell proliferation is established, yet melatonin's effect on thymus cell division was unexplored.
Purpose of the Study:
- To investigate the antiproliferative effect of melatonin on thymus cell division.
- To measure changes in histone H4 mRNA levels as an indicator of cell division.
- To explore potential circadian rhythms in melatonin's regulation of thymus cell proliferation.
Main Methods:
- Chronic administration of melatonin (high and low doses) to assess its impact on thymus cell division.
- Measurement of histone H4 mRNA levels to quantify cell proliferation rates.
- Analysis of the effects of single melatonin doses at various time points.
- Examination of melatonin's antiproliferative effects on Harderian gland, brain, lung, and kidney.
Main Results:
- Chronic melatonin administration significantly inhibited cell division in the thymus at both high (500 microg/body weight) and low (50 microg/body weight) doses.
- A circadian rhythm in histone H4 mRNA levels was observed, opposing known melatonin rhythms, suggesting negative regulation of thymus cell division by melatonin.
- A single dose of melatonin (50 microg/body weight) did not significantly decrease histone H4 mRNA levels within the studied time points, except after two hours.
- Melatonin demonstrated an inhibitory effect on the cell proliferation of Harderian gland, brain, lung, and kidney.
Conclusions:
- Melatonin exerts an antiproliferative effect on thymus cell division, indicated by reduced histone H4 mRNA levels.
- The findings suggest that melatonin negatively regulates cell division in the thymus, potentially through a circadian mechanism.
- Melatonin's antiproliferative effects extend to other organs, including the Harderian gland, brain, lung, and kidney.