Calcium channel blocker (diltiazem) inhibits apoptosis of vascular smooth muscle cell exposed to high glucose concentration through lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) pathway.
OBJECTIVE
to examine the role of diltiazem in the prevention of VSMC apoptosis exposed to high glucose through inhibition of LOX-1 expression.


METHODS
we performed experimental study on the primary culture of VSMCs. Expression LOX-1, and Caspase-3 activity (a key regulatory protease at which many signaling pathways merge for the execution of apoptosis) were measured by Elisa. Data were expressed as mean ± SEM. The statistical significance was assessed by one-way analysis of variance (ANOVA) followed by post hock analysis by Turckey test, p<0.05 was considered statistically significant.


RESULTS
chronic exposed VSMC to high glucose concentration (25 mM), increase cytosolic Ca++ concentration (3127 ± 413.89 v.s. 2011.81 ± 410.93 unit/cell, p<0.01), expression of LOX-1 ((506.80 ± 10.47 v.s. 458.40 ± 36.49 ng/ml, p<0.05), and caspase-3 activity (129.98 ± 5.97 v.s. 114.73 ± 10.84%, p<0.05) respectively, compare exposed to 5mM glucose concentration. LOX-1 was related to caspase-3 activity, pre-treated with inhibitor LOX-1 activity, k-carragenan before being exposed to glucose 25 mM, prevents the increasing of caspase-3 activity (96.41 ± 5.11 v.s. 129.98 ± 5.98 %, p<0.01). Pre incubation with 10μM of diltiazem before being exposed to 25 mM glucose concentration significantly inhibits the elevation of cytosolic Ca++ concentration (2149.61 ± 339.49 v.s. 3127 ± 413.89 unit/cell, p<0.01), LOX-1 expression (468,60 ± 14.44 v.s. 506.80 ± 10.47 ng/ml, p < 0.05), and caspase-3 activity (82.50 ± 9.90 v.s. 129.98 ± 5.97%, p<0.01).


CONCLUSIONS
overall, these results demonstrate that high glucose induces VSMCs apoptosis through caspase-3 pathway. This effect appears to be inhibited by diltiazem through decreasing LOX-1 expression and activity.
Rudijanto
Achmad
A
Department of Internal Medicine, Faculty of Medicine Brawijaya University - dr. Syaiful Anwar Hospital, Jl. Veteran, Malang 65145, Indonesia. perkeni_mlg@yahoo.com
D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D053148:Caspase 3 / Q000096:biosynthesis / Q000187:drug effects; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004110:Diltiazem / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005947:Glucose / Q000008:administration & dosage*; D006801:Humans; D007150:Immunohistochemistry; D007231:Infant, Newborn; D018613:Microscopy, Confocal; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D051127:Scavenger Receptors, Class E / Q000096:biosynthesis* / Q000187:drug effects; D015398:Signal Transduction
D002121:Calcium Channel Blockers; C495137:OLR1 protein, human; D051127:Scavenger Receptors, Class E; D053148:Caspase 3; D004110:Diltiazem; D005947:Glucose; D002118:Calcium