On the mechanisms of melatonin in protection of aluminum phosphide cardiotoxicity

Aluminum phosphide (AlP), one of the most
commonly used pesticides worldwide, has been the leading
cause of self-poisoning mortalities among many Asian
countries. The heart is the main organ affected in AlP poisoning.
Melatonin has been previously shown to be beneficial
in reversing toxic changes in the heart. The present
study reveals evidence on the probable protective effects of
melatonin on AlP-induced cardiotoxicity in rats. The study
groups included a control (almond oil only), ethanol 5%
(solvent), sole melatonin (50 mg/kg), AlP (16.7 mg/kg), and
4 AlP + melatonin groups which received 20, 30, 40 and
50 mg/kg of melatonin by intraperitoneal injections following
AlP treatment. An electronic cardiovascular monitoring device was used to record the electrocardiographic (ECG)
parameters. Heart tissues were studied in terms of oxidative
stress biomarkers, mitochondrial complexes activities,
ADP/ATP ratio and apoptosis. Abnormal ECG records as
well as declined heart rate and blood pressure were found
to be related to AlP administration. Based on the results,
melatonin was highly effective in controlling AlP-induced
changes in the study groups. Significant improvements
were observed in the activities of mitochondrial complexes,
oxidative stress biomarkers, the activities of caspases 3 and
9, and ADP/ATP ratio following treatment with melatonin
at doses of 40 and 50 mg/kg. Our results indicate that melatonin
can counteract the AlP-induced oxidative damage in
the heart. This is mainly done by maintaining the normal
balance of intracellular ATP as well as the prevention of
oxidative damage. Further research is warranted to evaluate
the possibility of using melatonin as an antidote in AlP
poisoning.