Rat carotid arteriotomy: c-myc is involved in negative remodelling and apoptosis.
OBJECTIVE
c-myc is the main proto-oncogene responsible for restenosis in cardiovascular surgery. The aim of our study was to evaluate the effects of c-myc antisense (AS) phosphorothioate oligodeoxynucleotides (ODNs) in the remodelling process induced by surgical carotid arteriotomy on an experimental rat model.


METHODS
Fifty-five rats with carotid stenosis and apoptosis induced by arteriotomy were submitted to gene expression analysis 4 h after surgery, to TUNEL assay 48 h after surgery and to histological analysis 30 days later.


RESULTS
AS ODNs induced a 60% decrease in target c-myc mRNA in injured carotid arteries compared to control sense and scrambled ODN-treated carotid arteries (P < 0.05). Histological evaluation revealed that stenosis stimulated by arteriotomy was mainly due to adventitial constrictive remodelling rather than to neointimal hyperplasia, observed only in a limited number of samples. Morphometric analysis showed that lumen area in c-myc AS ODN-treated carotid arteries was 35% greater than in control arteries (P < 0.05), whereas the media/lumen area ratio showed a 63% reduction in AS ODN-treated carotid arteries in comparison to control arteries (P < 0.05). Surgical injury affected the expression of apoptosis-related genes Bcl-2, Bax, Bcl-xL and Bcl-xS, inducing a mean 3.5-fold decrease in the Bcl-2/ Bax ratio and a 9-fold decrease in the Bcl-xL/S ratio 4 h after injury as compared with uninjured carotid arteries. TUNEL assay experiments revealed increased apoptosis in AS ODN-treated carotid arteries in comparison to control carotid arteries.


CONCLUSIONS
c-myc AS ODNs reduce the negative remodelling induced by arteriotomy. The imbalance between proliferative stimulus represented by surgery and the c-myc mRNA decrease induced greater apoptosis in AS ODN-treated carotid arteries without further affecting mRNA levels of Bcl-2, Bax, Bcl-xL and Bcl-xS genes.
De Feo
Marisa
M
Department of Cardiothoracic Sciences, Second University of Naples, Naples, Italy.
Forte
Amalia
A
Onorati
Francesco
F
Renzulli
Attilio
A
Cipollaro
Marilena
M
Cotrufo
Maurizio
M
Rossi
Francesco
F
Cascino
Antonino
A
D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D016893:Carotid Stenosis / Q000188:drug therapy* / Q000235:genetics* / Q000601:surgery; D015870:Gene Expression; D020287:In Situ Nick-End Labeling; D008297:Male; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D016271:Proto-Oncogene Proteins c-myc; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
D016376:Oligonucleotides, Antisense; D016271:Proto-Oncogene Proteins c-myc