抄録
The effects of porcine pancreatic elastase on rabbits fed high cholesterol diet were studied by histological and biochemical approach. Japanese white rabbits were fed with a 1% cholesterol diet every day for 20 weeks without or with 30mg i. p. of elastase injection. Plasma cholesterol levels at 20 weeks feeding of high cholesterol diet were 1, 558.9±100.1 and 981.8±78.4mg/dl in the control and elastase groups, respectively. Lipoprotein lipase (LPL) and postheparin lipolytic activities (PHLA) both in control and elastase groups were increased. However, the LPL and PHLA of the elastase group was significantly lower when compared to those of the control group. These increase of LPL and PHLA at 20 weeks-feeding of high cholesterol diet would be secondary response, because there were significant positive relationships between plasma or VLDL cholesterol and LPL (r=0.641, p<0.01, r=0.659, p<0.01, respectively).
ADP-induced platelet aggregation enhanced by the feeding on a high cholesterol diet was decreased in the elastase group. It would be suggested from this result that elatase decrease the ADP-induced platelet aggregation enhanced by high cholesterol diet.
The low sulfated glycosaminoglycans (GAG) of plasma, which reflect the tissue GAG contents, was lower in the elatase group than in the control group.
On the histological examination of the descending thoracic aorta just 2cm beneath aortic arch, the increase of elastic fibers, the accumulation of both in intima and media and duplication and rupture of internal elastic lamina in the elastase group were milder than those in the control group.
There was no differences of cholesterol content of aortic intima-media between both groups, while GAG content (mainly heparan sulfate and dermatan sulfate) of aortic intima-media in the elastase group were significantly lower than in the control group. The binding activity of aortic GAG to plasma LDL was significantly lower in the elastase group than in the control group.
It was suggested from the results of this study that the porcine pancreatic elastase may have the effects of lowering plasma cholesterol and metabolic changes in arterial GAG.
