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Mechanism of sphingosine‐1‐phosphate induced cardioprotection against I/R injury in diabetic rat heart: Possible involvement of glycogen synthase kinase 3 β and mitochondrial permeability transition pore
Author(s) -
Rana Ajay,
Sharma Saurabh
Publication year - 2016
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/1440-1681.12516
Subject(s) - cardioprotection , mitochondrial permeability transition pore , endocrinology , lactate dehydrogenase , medicine , pharmacology , agonist , ischemia , chemistry , biochemistry , enzyme , receptor , apoptosis , programmed cell death
Summary There is growing evidence that diabetes mellitus causes attenuation of the bioactive metabolite of membrane sphingolipids, sphingosine‐1‐phosphate, and this may be a key mechanism in the decreased cardioprotective effect of ischaemic preconditioning ( IPC ) in the diabetic heart. Thus, this study has been designed to investigate the role and pharmacological potential of sphingosine‐1‐phosphate in diabetic rat heart. Diabetes was produced in Wistar rats by administration of a low dose of streptozotocin ( STZ ) (35 mg/kg, i.p., once) and feeding a high fat diet ( HFD ) for 6 weeks. Isolated rat heart was subjected to 30 min ischaemia followed by 120 min of reperfusion (I/R). The heart was subjected to pre‐ischaemic treatment (before ischaemia for 20 min) and pharmacological preconditioning with the S1P agonist FTY 720 (0.6 μ mol/L) with and without atractyloside (an mPTP opener; in the last episode of reperfusion before I/R). Myocardial infarction was assessed in terms of increase in lactate dehydrogenase ( LDH ), creatinine kinase‐ MB ( CK ‐ MB ), myeloperoxidase ( MPO ) level and infarct size (triphenyltetrazolium chloride staining). Immunohistochemistry analysis was done for assessment of tumour necrosis factor ( TNF )‐ α and glycogen synthase kinase ( GSK )‐3 β level in cardiac tissue. Pre‐ischaemic treatment and pharmacological preconditioning with FTY 720 significantly decreased I/R‐induced myocardial infarction, TNF ‐alpha, GSK ‐3 β level and release of LDH and CK ‐ MB as compared to control group. The cardioprotective effect of S1P agonist was significantly attenuated by atractyloside. It may be concluded that S1P agonist FTY 720 prevents the diabetic heart from ischaemic reperfusion injury, possibly through inhibition of GSK ‐3 β and regulation of opening of mitochondrial permeability transition pore.