[Study on inducing an artemisinin-resistant line of Plasmodium berghei].

Objective: To induce a line of Plasmodium berghei with resistance to artemisinin.

Methods: The major methods included blood transmission from passage to passage and progressive increase of drug pressure.

Results: The resistant lines were developed by different protocols: (A) The initial dosage of artemisinin was 126.2 mg/kg which was increased by 60 mg/kg for the next passage and boosted by 126.2 mg/kg for every other passage. As developed to passage 60 and 76, the resistant index was 18.39:1 and 14.89:1 respectively, then decreased gradually. For passage 108, the dosage was 8,862.5 mg/kg, but the resistant index was only 10.49:1. (B) Using passage 66 from (A) as the source, a dosage of 4,000 mg/kg was given each week, the resistance of the passage 40 increased significantly with an index of 27.5:1. (C) Using passage 19 of (B) as the source, drug was administered at the dose of 2,000 mg/kg each week. The resistant index of passage 15 was 17.41:1.

Conclusion: Line of P. berghei with medium level resistance to artemisinin was established.