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Parasit Host Dis > Volume 18(2):1980 > Article

Original Article
Korean J Parasitol. 1980 Dec;18(2):192-198. English.
Published online Mar 20, 1994.  http://dx.doi.org/10.3347/kjp.1980.18.2.192
Copyright © 1980 by The Korean Society for Parasitology
Morphological observations on Clonorchis sinensis obtained from rats treated with praziquantel
Han-Jong Rim,Hee-Young Park,Soo-Jin Kim and Sook-Hee Lee
Department of Parasitology and Institute for Tropical Endemic Diseases, College of Medicine, Korea University, Korea.

The present study was undertaken to observe the morphological changes of Clonorchis sinensis obtained from experimentally infected rats treated with praziquantel (Biltricide®) which is a new anthelmintic agent with high activity against a broad spectrum of cestode and trematode species.

For this study, the rats were infected experimentally with about 50 metacercariae of C. sinensis and were given praziquantel a single dose of 600 mg per kg of body weight at 5 weeks after infection. The Clonorchis worms were isolated from the bile ducts of the rats which were autopsied on the 4th day after treatment. After isolation the parasites were observed their shape and motility in the medium of 37℃ physiological saline solution, and then the fine structure of the tegument of C. sinensis was studied by means of light, scanning and transmission electron microscope. The findings of the observation were compared with those of untreated parasites.

The results are as follows:

1. All the isolated worms moved actively in the medium of physiological saline solution (37℃). A majority of the parasites obtained from the treated rats showed a large balloon shaped structure on the surface between oral and ventral suckers. But such structure has never seen in the parasites obtained from control rats.

2. By the scanning electron microscopic observation, the regular pattern of the tegumental ridges was significantly changed on the outer surfaces of parasites obtained from the treated rats as compared with those of the control rats.

3. By the transmission electron microscopic observation, the numerous mitochondriae in the syncytial tegumental layer of the treated parasites appeared to be degenerated and formed small vacuoles, and the tegumental ridges were also degenerated and showed somewhat flattened.

4. In the parasites obtained from the treated rats, a different size of vacuoles interspersed in the distal part of the syncytial tegument and also in subepithelial region of the urinary bladder. These vacuoles are fused each other and lead to the disruption of the apical region of syncytial tegument along the basement layer. Finally the basement layer was dislocated. So that the tegumental layer appeared as a large balloon.


Fig. 1
SEM (Scanning electron microscopy) of control C. sinensis. Showing anterior part of worm and oral sucker (Os) ×36.

Fig. 2
SEM of treated C. sinensis. Showing balloon shaped structure (Ba) between oral (Os) and ventral suckers. ×72.

Fig. 3
SEM of the surface of untreated worm. Showing regular pattern of tegumental ridges (TR). ×4,200.

Fig. 4
SEM of the surface of treated worm. Showing degenerated tegumental ridges (TR). ×4,400.

Fig. 5
TEM (Transmission electron microscopy) of the tegument of control worm. Showing the organization of syncytial tegument (STg) with tegumental ridges (TR), basement membrane (Bm), longitudinal musculature (LM) and mitochondria (Mi). ×15,000.

Fig. 6
TEM of the tegument of treated worm. Showing degenerated mitochondria (Mi) in the syncytial tegument (STg). ×15,000.

Fig. 7
TEM of the epithelial region of excretory bladder of treated worm. Showing many different size of vacuoles (V) and microtubules (Mt). ×10,000.

Fig. 8
TEM of the surface of treated worm. Showing degenerated tegumental rideges (TR). ×10,000.

1. Baelz E. Berl Klin Wochenschr 1883;1883:234–238.
2. Becker B, Mehlhorn H, Andrews P, Thomas H. Scanning and transmission electron microscope studies on the efficacy of praziquantel on Hymenolepis nana (Cestoda) in vitro. Z Parasitenkd 1980;61(2):121–133.
3. Becker B, Mehlhorn H, Andrews P, Thomas H, Eckert J. Light and electron microscopic studies on the effect of praziquantel on Schistosoma mansoni, Dicrocoelium dendriticum, and Fasciola hepatica (Trematoda) in vitro. Z Parasitenkd 1980;63(2):113–128.
4. Cobbold S. Lancet 1975;2:427.
5. Fujino T, Ishii Y, Cho DW. Surface ultrastructure of the tegument of Clonorchis sinensis newly excysted juveniles and adult worms. J Parasitolq 1979;65(4):579–590.
6. Ichzika K. Igaku Zasshi 1876;40:20–26.
7. Iijima I. J Coll Sci Imp Univ Tokyo 1886;1:47–59.
8. Inatomi S, et al. Jpn J Parasit 1968;17:395–401.
9. Jeong KH, Rim HJ, Kim CW. [A Study On The Fine Structure Of Clonorchis Sinensis, A Liver Fluke: 1. The Body Wall And The Nervous System]. Korean J Parasitol 1978;16(2):156–164.
10. Kang RS. Yonsei J Med Sci 1968;1:97–109.
11. Kim CH. [Ultrastructure of the integument of adult Clonorchis sinensis]. Korean J Parasitol 1968;6(3):111–122.
12. Komiya Y, Kawana-Tajimi T. The development of the excretory system of Clonorchis sinensis in its definitive host. Jpn J Med Sci Biol 1953;6(6):571–575.
13. Kobayashi H. Centralbl Bakt Parasit Orig 1915;75:299–318.
14. Looss A. Ann Trop Med Parasit 1907;1:271–274.
15. Rim HJ, et al. Korea Univ Med J 1979;16:459–470.
16. Rim HJ, Ha JH, Kim SJ. [Experimental study on the therapeutic effect of praziquente1(Embay 8440) in rats experimentally infected with Clonorchis sinensis]. Korean J Parasitol 1980;18(1):65–80.
17. Thomas H. [Experimental results with praziquantel (Embay 8440) in cestodiasis and cysticercosis (author\'s transl)]. Bol Chil Parasitol 1977;32(1-2):2–6.
18. Thomas H, Gönnert R. The efficacy of praziquantel against cestodes in animals. Z Parasitenkd 1977;52(2):117–127.
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