OBJECTIVETo construct the life cycle of Angiostrongylus cantonensis (A.cantonensis) in laboratory condition.

METHODSSD rats were infected orally with the third-stage larvae of A.cantonensis collected from Jiangmen, Guangdong province. Six weeks after infection, the first-stage larvae were isolated from fresh feces of the rats by using Baermann funnel to infect 25 second-generation white jade snails raised in laboratory at the daily dose of 300 000 for 3 consecutive days. Three weeks later, the snails were dissected for counting the third-staged larvae of A.cantonensis, and those positive for A.cantonensis infection were fed directly to 10 fasting rats. The serum samples of the rats were then collected 2 weeks later for examination of specific antibodies using ELISA. The feces of the infected rats were examined microscopically after 6 weeks, and the brain, heart and lungs of the infected rats were dissected to observe the larvae at 3, 5, and 8 weeks, respectively.

RESULTSThe 3-stage larvae of A.cantonensis were found in the second-generation snails 3 weeks after infection. The positivity rate of serum specific antibodies was 100% in the 10 rats 2 weeks after feeding of the infected snails. The 1-stage larvae were detected in the feces of the rats 6 weeks after infection, and the fourth-stage larvae were found in the brain of the rats at 3 weeks, while adult worm and eggs were found in the heart and lungs of the infected rats at 5 and 8 weeks.

CONCLUSIONThe successful establishment of human colon carcinoma cell line with PRL-3 gene knock-down provide a basis for investigation of the role of PRL-3 gene in the metastasis of human colorectal carcinoma.