Loading of vitamin A in rabbits infected by Clonorchis sinensis
Clonorchis sinensis principally lives in the bile bucts absorbing nutritional
substances and leading to chronic peribiliary inflammation due to mechanical
irritation. During infection of Clonorchis sinensis, nightblindness frequently
appears due to deficiency of vitamin A (vit. A). Levine (1958) observed one case of
nightblindness in the experimental infection of Amphimerus pseudofelineus of cat.
However, Bercovitz(1931) reported previously the symptom could disappear on
inducing the excretion of bile from the duct.
Lewis(1942) observed that the serum vit. A decreased when residual vit. A in the
liver tissue was exhausted. Kim (1964), recently, reported that vit. A loading in
infected animal caused the temporary raising of serum value.
The object of the present study is to confirm the fate of vit. A which was
absorbed from the intestinal wall of the rabbit infected with Clonorchis sinensis
and to clarify the mechanism of the vit. A deficiency.
Materials and Methods
Animals: White rabbits(1.6∼2.0kg) were used as experimental animals and were fed
Metacercariae: Metacercariae of Clonorchis sinensis were collected by digestion
method from fresh water fish caught from an endemic area (Iri Chollabuk-Do).
About 1,500 of the larvae were given orally, and 6 weeks after the infection
egg-out-put was confirmed by stool examination.
Vitamin A: Water soluble(U.S. vitamin corportion). For loading 15,000㎍ of vit. A
was given orally and 3,000 ㎍ intravenously.
In order to calculate the vit. A, Georgy modification of Dann & Evelyn method was
applied for serum vit. A, and Oser, Melnick Pader's method for tissue vit. A. 3∼4
gm of liver tissue weighed and sliced into small pieces and followed by the regular
procedure. A number of Clonorchis sinensis from the bile duct were washed with
saline several times and followed the same procedure. Vit. A in bile juice and
urine was measured by the same method, except replacing the 0.5 N alcoholic
potassium hydroxide into 95% ethyl alcohol in order to coagulate the protein
Blood was taken from the heart at hunger condition at intervals of two hours in
the first part and three hours in the second part(13 hours after the vit. A was
given). the separated serum was kept at freezing temperature.
The average serum vit. A in healthy rabbits was 71.1㎍% and infected group was
30.8 ㎍% 7 weeks after the infection.
When vit. A was given to non-infected group (15,000㎍), the serum value increased
to high level(198.1, 264.6, 222.4 ㎍%) from 7 to 16 hours. the decrease started
after 19 hours and recovered to original lvel after 25 hours.
In the infected group, though there were individual differences, the value of
vit. A in the serum increased to high level (296.8, 351.3, 320.7 ㎍%) from 7 to 16
hours after the administration of vit. A and showed acute decrease at 19 hours to
160.6㎍%, but still held high titre, 85.9 ㎍% even 25 hours after the loading.
In general, there was no difference of the ability of vit. A absorption between
the infected and non-infected group, but the value of vit. A in the serum after the
loading was much higher in the infected group than in non-infected.
The amount of vit. A in liver parenchyma was also calculated before and after
vit. A was given. In the infected rabbits, the weight of the liver parenchyma
increased to about 1.6 times as in the normal rabbit due to dilatation, rupture of
the capillary bile ducts, necrosis of liver parenchyma and degeneration of the
cells. However the amount of vit. A in the liver parenchyma was 61.84 ㎍/gm in the
normal group and only 13.82㎍/gm in infected group. 7 hours after vit. A was given
in the normal group the amount increased to about 1.7 times (104.53㎍/gm), but in
infected group there were no differences comparing the value before the loading,
16.56 ㎍/gm after 3 hours, 12.81 ㎍/gm after 7 hours.
In order to clarify the reason of the low value of vit. A in the liver parenchyma
of infected group, whether it was due to the loss of vit. A by means of bile juice
or consumption by the liver fluke itself, the bile juice and parasites were
Bile juice was taken from common duct hourly(normal rabbit 13 ml, moderatry
infected rabbit 9 ml, heavily infected rabbit 3 ml), but no vit. A was detected
even from the vit. A loaded group and the vit. A could not be found from the
parasite itself collected from biliary ducts numbering 600 and 1,800.
Since the storing ability of liver parenchyma in the infected group was lower
than in the normal group, the process of the rapid decrease along with time elapes
was one of the subjects to be clarified.
The amount of vit. A in kidney tissue, urine, and feces were measured comparing
the normal group. Since it took much time to get sufficient amount of stool from
the rabbit, the animals were sacrificed after a certain given time, and stool was
taken from the lower colon.
In the kidney a slight amount of vit. A was detected, bud there was no difference
between the normal and infected group. 36 hours after the vit. A loading, the
amount of vit. A in urine of normal rabbits were 22.7 ㎍ in average, whereas it was
82.7 ㎍ in the infected group. The data shows that loss of vit. A from urine in the
infected group is about 4 times that of the normal group.
The amount of vit. A in feces showed no difference between the two groups. It is
presumed a considerable amount of vit. A is excreted without absorption from the
In conclusion, it is considered that the reason of vit. A deficiency in the
infection of Clonorchis sinensis is due to the decrease of storing ability of the
liver and rapid excretion from kidney, and not by the absorbability of vit. A form
the intestinal wall.