Effects Of All-transretinoic Acid On Vascular Smooth Cell Apoptosis Of Carotid Atherosclerosis And The Expression Of Fas In Rabbit

Objective: to observe the effects of all-transretinoic acid on vascular smooth cell apoptosis of carotid atherosclerosis and the expression of Fas in rabbit.Methods: Forty-eight New Zealand rabbits were divided randomly 4 groups: normal diet group (NOR n=12), control group (CON n=12), surgery group (SUR n=12) and atRA treat group (TRE n=12). The last three groups were fed by high cholesterol forage. The SUR and TRE groups were made up atherosclerotic model by air desiccation endothelial injury. The TRE group was fed by all-transretinoic acid. On the 4th and 6th week, the target vessel was taken out. The intima hyperplasia was observed by microscopy through HE . Cell apoptosis was determined by TUNEL stain and Fas was observed by immunostaining.Results: In SUR group, there were distinct neointima formation and narrow luminal area at 4th and 6th week . Histomorphometry revealed that the area of lumina was distinct between TRE and SUR (at 4^th week, TRE=0.332 nun², SUR=0.612 mm² ,p<0.01). The area of neointima was the highest in SUR, second TRE and the lowest CON groups (at 4th week, IA=0.389 mm² , 0.113 mm², 0.102 mm² respectively, p<0.01). The positive staining of TUNEL in TRE was significantly abundant than in SUR and CON in neointima (positive cell ratio:18.40%,1.02%,1.07% respectively, p<0.01). The expression of Fas in TRE was more than the other groups (positive cell ratio : 16.72% , 9.21%, 1.34% respectively, p<0.01).Conclusion: all-transrotinoic acid may induce apoptosis of VSMC in atherosclerosis and suppress the proliferation of intima in vessel injury .the mechanism of apoptosis of VSMC is Fas/FasL approach.