미역이 Lanolin 식이성가토(食餌性家兎) 동맥경화증에 미치는 영향

Abstract

[한글]

[영문]

Studies on human atherosclerosis indicated that there exists a geographical

difference in the incidence and severity of atherosis and coronary diseases.

Investigations on migrating races, such as Japanese, Jews and Italians, strongly

suggested that the difference is not related to racial but to dietary difference.

For instance, the incidence and severity of atherosclerosis among Japanes in Japan

is much lower than those among Japanese Nisei in the United States, and those among

Japanese Nisei in Hawaii are inbtween, which corelated well with the differece of

their dietary constituents in each locality(Larson 1957. Ket et al. 1958, Gore et

al. 1960).

However, the role of diet in the development of atherosclerosis has been

controversial subject of many year,s raning from the view that it is trivial to the

belief that the diet is the primary cause of epidemic atherosclerosis. The belief

that diet plays an important role in atherogenesis arose from the fact that

experimental therosclerosis is produced exclusively with dietary manupulation,

particularly by feedig with high cholesterol diet, and the data obtained from the

animal experiments were extrapolated to the human. Keys (1955) hypothesised that

atherogenesis is promoted by increasing concentration of blood cholesterol and the

blood cholesterol level is directly influenced by the amount of fat in the diet.

However, with the accumulation of new information, it is becoming evident that the

role of lipids in atherogenesis is more complex than it was originally thought.

Investigations of may nutrients other than fat as to the effect on serum

cholesterol have also been made. So far vitamines and proteins seemed to have no

effect on serum cholesterol (Keys and Anderson 1957). In the United States and

Britain a general tendency of cardivoascular disease rate seems to be inversely

related to the hardness of local drinking water (Morris et al. 1961), but this has

not been proved scientifically. Keys et al. (1960,1961) observed that complex

carbohydrates have a lowering effect of serum cholesterol and thought that this

might explain the low serum cholesterol level in the people who eat a high

carbohydrate diet.

The Present study attempts to investigate the influence of sea-weed, a common

item in the Korean diet, on serum cholesterol and experimental atherosclerosis in

rabbits following excessive feeding with lanolin.

Materials and Methods

Fifty rabbits, ranging from 1.5 to 2.0 kg of body weight, wer divided into five

groups and treated as follows.

Group Ⅰ consisted of 15 animals fed with lanonlin only, group Ⅱ of 20 animals

fed with lanolin and sea-weed, group Ⅲ of 5 animals fed with lanolin and

thyroxine, group Ⅳ of 5 animals fed with sea-weed only, and group Ⅴ of 5 animals

used as untreated controls.

All animals were fed a basal diet of bean curd-residue, 300 gms per day. the

lanolin was given 10 gms per animal per day orally for 75 days. The

sea-weed(undaria pinatifida) was prepared in dry powder and given 1.0 gm per animal

per day alone and in combination with lanolin feeding. Thyroxine was give 1 mg per

animal per day in combinaton with lanolin feeding. Thyroxine was administered

becauseof a possible effect sea-weed might have on the thyroid gland in view of the

high iodine content in sea-weed.

During the expreimental period, body weight, serum total cholesterol and

phospholipids determinations were made twice. All animals were killed and

necropsied 75 days after the feeding of lanolin. the aortas, coronary arteries,

liver, adrenals, and thyroid gland were examined grossly and microscopically.

Results and Summary

Serum total cholesterol was markedly elevated in the animals treated with anolin

alone. The animals treated with lanolin combined with ssa-weed also showed

increased serum cholesterol, but to a lesser degree.

The aortas and coronary arteries showed various degrees of atheromatous changes

in the animals fed with lanolin only, including a complete occlusion of coronary

arteries in some cases. The atheromatous changes also developed in animals fed with

lanolin in combination with sea-weed, but its degree was greatly reduced. The liver

showed moderate degree of lipids deposition in animals fed with lanolin alone, and

it was very light in animals fed with sea-weed in combination with lanolin. The

adrenals exhibited heavy lipid accumulation in the cortex both in groups treated

with lanolin alone and lanolin with sea-weed, without any notable difference

between two groups.

The administration of thyroxine with lanolin produced the similar changes to

lanolin alone.

The data obtained from the present experiment indicates that sea-weed depresses

lanolin induced hypercholesterolemia and lanolin-induced atherosclerosis in

rabbits. The inhibiting effect of sea-weed on the atheroma formation appears to be

due to its depressing action on hypercholesterolemia. A possible mechanism of the

depressing action of sea-weed on serum cholesterol may be the action of iodine and

iodides in sea-weed.