Response of Mast Cell in Mice Experimentally Infected with Clonorchis sinensis

BALB/c mice were used and divided into 2 experimental groups ; group 1, infected with a single dose of 50 Clonorchis matacercariae and group 2, challenged with 50 metacercariae at the 4th week after primary infection with the same dose of metacercariae. Normal mice were served as control. Three mice in each group were examined weekly for 10 weeks. Mice in groups 1 and 2 were sacrifficed. Liver including gall bladder and common bile duct was group were intraperitoneally injected with ethanol and fixed. The liver including common bile and sectioned serially and stained with toluidine blue for examination of appearance degree of mast cells. The medenterium was used for examination of appearance degree of mast cells and percentage of degranulating cells.

The results obtained in this study are summarised as following:

1) Average number of worm recovered was 13.1 in group 1 and 15.7 in group 2, respectively, throughout the examination. Mean number by week after reinvection in group 2 revealed a slight increase, ranging from 3.0 to 9.0, comparing with those in group 1.

2) In control mast cells were found in the mesenterium, but not in the bile duct, small intestine and lymphnodes. No mast cells were found in the small intestine in groups 1 and 2. In group 1 nast cells showed a moderate appearance degree at the 3rd week and persisted for 2-4 weeks in the bile dust, mesenterium and lymphnodes. Group 2 shoeed a moderate or marked degree ehich persisted for longer period after reinfection in the tissues.

3) Average percentage of degranulating cells in the mesenterium was 9.1% in control and 26.3% in froup 1, respectivley, throughout the examination and 51.7% during 6 weeks after reinfection in group 2. The peak was 36.7% at the 3rd week after primary infection in groups 1 and 2. In group 2, the percentage of degranulating cells increased promptly and markedly to 77.3% at the 1st week after reinfection.

4) Chronological of appearance degree of mast cells and percentage of degranulating cells in the tissues, particularly in the bile duct showed an obvious tendency to parallel to chronological change of number of worm recovered in the liver.

From the adove results, it is strongly suggested that mast cells in mice infected with Clonorchis sinensis are deeply implicated in expulsion of worms in bile dust.