Melatonin protects mast cells against cytotoxicity mediated by chemical stimuli PMACI: Possible clinical use

- PMACI induces cytotoxicity on mast cells in a dose and time dependent manner.
- Melatonin protects the mast cells against PMACI chemical stimuli.
- Pharmacological doses of melatonin are the most effective for cytoprotection.
- The action of melatonin is mediated via dependent and independent membrane receptors.
- Melatonin could be a stabilizing cell molecule in various inflammatory conditions.

Melatonin has documented cytoprotective effects on a wide variety of immune cells. The mechanism of action on mast cells (RBL-2H3) still remains in the dark. We found that melatonin significantly attenuated phorbol 12-myristate 13-acetate plus calcium ionophore A23187 (PMACI)-induced cytotoxicity in a concentration and time-dependent manner. It appears that the effect of melatonin on mast cells is two-fold: dependent (MT1 and MT2) and independent membrane receptors. In conclusion, melatonin treatment reduced the cytotoxicity, mediated by PMACI, and could provide a useful therapeutic option in processes where an excessive activation of mast cells occurs.