Hypercholesterolemic diet induces vascular smooth muscle cell apoptosis in sympathectomized rats via intrinsic pathway.
In this study, we intend to investigate the role of hypercholesterolemic diet, a high risk factor for atherosclerosis, on vascular cell apoptosis in rats that have been previously sympathectomized. Thus, newborn male Wistar rats received injections of guanethidine for sympathectomy. Sham received injections of vehicle. The two groups were fed 1% cholesterol diet for 3months. Sympathectomy alone group was also exploited. Apoptosis in abdominal aortic tissue was identified by TUNEL method and conventional agarose gel electrophoresis to detect specific DNA fragmentation. Caspases 3 and 9, Bcl-2, Bax and cytochrome c were examined by immunoblotting. Oil Red O staining was used to reveal lipid in the arterial wall. Vascular smooth muscle cells (VSMCs) and macrophages were identified by immunostaining for α-smooth muscle actin and rat macrophage marker (ED1), respectively. The efficacy of sympathectomy was evaluated by analysis of perivascular sympathetic fibers. Our study showed that hypercholesterolemic diet, when performed in rats with neonatal sympathectomy, 1) increased aortic TUNEL-positive cells compared to sham and sympathectomy alone groups, 2) illustrated a typical apoptotic DNA ladder on agarose gel electrophoresis, 3) induced Bax translocation from cytosol to mitochondria, 4) enhanced cytochrome c release from mitochondria to cytosol, 5) increased expression of active caspases 3 and 9, and 6) decreased Bcl-2 expression. VSMCs are identified as the major cell type exhibiting apoptosis in this model. Taken together, it can be concluded that hypercholesterolemic diet, when performed in rats with neonatal sympathectomy, induces vascular cell apoptosis in an intrinsic pathway.
Laboratoire d Étude de Pathologies Vasculaires, Unité de Physiologie Intégrée, Faculté des Sciences de Bizerte, 7021 Jarzouna, Tunisia; Laboratoire d Étude de la Microcirculation (EA 3509), Université Paris 7, France; Laboratoire de Biochimie, Hôpital Lariboisière, Paris, France. Electronic address: rafik.hachani@fsb.rnu.tn.
Rafik
R
Hachani
Laboratoire d Étude de Pathologies Vasculaires, Unité de Physiologie Intégrée, Faculté des Sciences de Bizerte, 7021 Jarzouna, Tunisia.
Houcine
H
Dab
Laboratoire d Ecophysiologie Animale, Faculté des Sciences de Sfax, 3000, Tunisia.
Anouar
A
Feriani
Faculté de Médecine de Sfax, 3000, Tunisia.
Sami
S
Saber
Laboratoire d Étude de Pathologies Vasculaires, Unité de Physiologie Intégrée, Faculté des Sciences de Bizerte, 7021 Jarzouna, Tunisia.
Mohsen
M
Sakly
Laboratoire d Étude de la Microcirculation (EA 3509), Université Paris 7, France.
Eric
E
Vicaut
Laboratoire de Biochimie, Hôpital Lariboisière, Paris, France.
Jacques
J
Callebert
Laboratoire d Étude de la Microcirculation (EA 3509), Université Paris 7, France.
Richard
R
Sercombe
Laboratoire d Étude de Pathologies Vasculaires, Unité de Physiologie Intégrée, Faculté des Sciences de Bizerte, 7021 Jarzouna, Tunisia.
Kamel
K
Kacem
D000199:Actins / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001012:Aorta, Abdominal / Q000503:physiopathology*; D017209:Apoptosis / Q000502:physiology*; D053938:DNA Fragmentation; D004032:Diet / Q000009:adverse effects; D004195:Disease Models, Animal; D006145:Guanethidine; D006937:Hypercholesterolemia / Q000503:physiopathology*; D008264:Macrophages / Q000502:physiology; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000503:physiopathology*; D032389:Myocytes, Smooth Muscle / Q000502:physiology*; D017208:Rats, Wistar; D015398:Signal Transduction; D013563:Sympathectomy, Chemical; D013564:Sympathetic Nervous System / Q000503:physiopathology
D000199:Actins; D006145:Guanethidine
Aorta; Apoptosis; Hypercholesterolemia; Intrinsic pathway; Rat; Sympathectomy