Inhibition of mitochondria responsible for the anti-apoptotic effects of melatonin during ischemia-reperfusion.
OBJECTIVE
To investigate a possible mechanism responsible for anti-apoptotic effects of melatonin and provide theoretical evidences for clinical therapy.


METHODS
Ischemia-reperfusion mediated neuronal cell injury model was constructed in cerebellar granule neurons (CGNs) by deprivation of glucose, serum and oxygen in media. After ischemia, melatonin was added to the test groups to reach differential concentration during reperfusion. DNA fragmentation, mitochondrial transmembrane potential, mitochondrial cytochrome c release and caspase-3 activity were observed after subjecting cerebellar granule neurons to oxygen-glucose deprivation (OGD).


RESULTS
The results showed that OGD induced typical cell apoptosis change, DNA ladder and apoptosis-related alterations in mitochondrial functions including depression of mitochondrial transmembrane potential (its maximal protection ratio was 73.26%) and release of cytochrome c (its maximal inhibition ratio was 42.52%) and the subsequent activation of caspase-3 (its maximal protection ratio was 59.32%) in cytoplasm. Melatonin reduced DNA damage and inhibited release of mitochondrial cytochrome c and activation of caspase-3. Melatonin can strongly prevent the OGD-induced loss of the mitochondria membrane potential.


CONCLUSIONS
Our findings suggested that the direct inhibition of mitochondrial pathway might essentially contribute to its anti-apoptotic effects in neuronal ischemia-reperfusion.
Han
Yi-xiang
YX
Institute of Medical Science, First Affiliated Hospital, Wenzhou Medical College, Wenzhou 325000, China. yxhan2001@163.com
Zhang
Sheng-hui
SH
Wang
Xi-ming
XM
Wu
Jian-bo
JB
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002531:Cerebellum / Q000473:pathology; D045304:Cytochromes c / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D053938:DNA Fragmentation; D005947:Glucose / Q000378:metabolism; D015151:Immunoblotting; D008550:Melatonin / Q000378:metabolism / Q000494:pharmacology*; D008564:Membrane Potentials; D008928:Mitochondria / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015424:Reperfusion; D015427:Reperfusion Injury; D013997:Time Factors
D045304:Cytochromes c; D052248:Nitric Oxide Synthase Type I; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D005947:Glucose; D008550:Melatonin; D010100:Oxygen