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ABSTRACT Atherosclerosis (AS) is the principle cause of cardiovascular disease. For many years, AS was regarded as irreversible. However, recent accumulated evidence suggests that AS can regress with proper manipulation. Studies from animal models show that low cholesterol diet can induce obvious regression of AS plaques; Drugs, such as probucol, clolestyramine, lovastatin, isradipine, fosinopril, etc, can reverse the AS respectively by manipulating plasma lipoprotein, scavenging free radicals, blocking calcium channel or inhibiting an-giotensin converting enzyme. Clinical trials furthersubstantiate that good lifestyle and effective control of plasma lipoprotein can reduce clinical events and cause AS plaques regression. Although, AS plaques can regress is no longer in doubt, the mechanism is still unknown. The HDL-mediated reverse cholesterol transport system, apoptosis of the plaque cells may play an important role.
ABSTRACT
AIM To observe the effects of the combination of heparinoid, aspirin and losartan on the experimental vascular intima hyperplasia induced by squeezing carotid artery in rats. METHODS Rats except the normal control group were under operation after two days oral administration once a day. At the second hour after injury, blood coagulation time(CT), time of arterial thrombus formation by electrical stimulus(ATFTES) and the level of TXB_2 in plasma were measured. At the fourteenth day after the surgery, the following indexes were examined: intima/media ratio, intima area ratio, PDGF-B and PCNA immunohistochemistry in carotid artery. RESULTS CT, TATFES increased and the level of TXB_2 decreased in the groups of Hep, Asp and Hep+Asp. The PDGF-B content, the positive ratio of PCNA and the inti- ma/media ratio also decreased in the groups of Hep, Asp, Los, Hep+Asp, Hep+Los and Asp+Los. Compared with single drug or two drugs combination, PDGF-B, positive ratio of PCNA, intima/media ratio and intima area ratio decreased significantly in the group of three drugs combination( P
ABSTRACT
AIM To establish a model of vascular intima hyperplasia for study the restenosis after angioplasty. METHODS Carotid artery of rat was exposed under general anesthesia. Two pieces of steel slides(13 mm?5 mm?1 mm) were set on and under the carotid artery separately. Then the slides were squeezed by two surgical forceps paralleling to the artery for 25 min. Histomorphological study was performed at the second hour or on the fourteenth day after operation. RESULTS At the second hour after operation, the loss of endothelial integrity and platelet deposition were seen under the scanning electromicroscopy. Under the light microscopy, there were infiltration of inflammatory cells in vessel wall andthrombus formation in the vessel cavity. At the fourteenth day after operation, PCNA positive cells in vessel wall of squeezed artery were significantly higher, the ratios of intima, medium and intima areas of squeezed artery were significantly increased and the ratio of cavity area of squeezed artery was significantly decreased compared with those of uninjured artery.The vascular intima hyperplasia and PCNA positive cells in squeezed arterial wall were inhibited by oral administration of heparinoid and aspirin. CONCLUSION With squeezing carotid artery in rats the vascular intima hyperplasia as restenosis after angioplasty was established.