Influence of sea-weed upon the lanolin-induced atherosclerosis in rabbits
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
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
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
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.