Effect of soysterol obtained from soybeans was studied referring to rise and fall of aortic pulse wave velocity (PWV) of rabbits with experimental arteriosclerosis, observation of arterial wall constituents and assay.
Twenty-seven male rabbits of 38 months were divided into the healthy group (H group) of 13 rabbits, the sclerotic group (S group) of 9, and the soysterol administration group (A group) of 5 respectively. For producing arteriosclerosis, N2 gas inhalation, intramuscular injection of norepinephrin and oral administration of cholesterol were used combinedly. To the A group at the same time as loading 200 mg of soysterol (Moristerol®) was given once a day. PWV and blood pressure were measured every two weeks to see their rise and fall. After 22 weeks all the rabbits were killed and 6 components in media of thoracic aorta, namely, smooth muscle cell (SMC), nuclear DNA (DNA), elastin (EL), collagen (CL), acid mucopolysaccharides (AMPS), and glycoprotein (GP) were observed histochemically by MSP and assayed. Furthermore, a series of principal component analysis was conducted to generally evaluate differences among those 3 groups as to changes of those 6 components. When rise and fall of PWV in those 3 groups were observed with average regression coefficient, it was 0.0109 m/sec/W with the H group, 0.0626 m/sec/W with the S group and-0.0326 m/sec/W with the A group, showing the lower value with the A group than that of the S group. An average PWV changes (ΔPWV) in every 3 months was hardly observed in the H group, but in the S group after 6 weeks, it increased by 0.9 m/sec on an average. On the other hand in the A group during the total course, an apparent decreasing trend was observed, and a significant decrease was noted 6 weeks after starting of administration onward. Upon histochemical observation, atrophy, disappearance and decrease of SMC, fragmentation and disappearance of EL and CL, uneven distribution and increase of AMPS and GP, and increase of calcium phosphate were noted in the S group, while in the A group either component received only mild disturbances, showing intermediary values between H group and S group. Amount of the components with the H group, S group and A group respectively were as follows
SMC: 40.6±6.6, 32.6±4.4, 40.6±8.0% E
DNA: 293.8±61.8, 283.1±51.2, 316.0±74.9% E
EL: 52.8±4.3, 42.3±2.6, 51.6±7.5% E
CL: 38.8±4.0, 33.3±3.7, 37.3±1.8% E
AMPS: 28.4±6.6, 35.7±5.4, 32.7±2.7% E
GP: 33.2±3.7, 39.7±5.3, 36.1±3.8% E
Upon principal component analysis and a study of their distribution on the quadratic coordinates in comparison of those 3 groups, it was suggested that distribution of the A group being near the region of the H group, soysterol has an antiarteriosclerotic effect.
