Histological and histochemical effects of tribendimidine on Necator amerzcanus

Tribendimidine (N. N/-bis[4-(l-dimethylamino) ethyliderie aminophenyl]1,4-phenylene-dimethylidyneamine) synthesized by this Institute was more stable than amidantel. To evaluate the mode of action of tribendimidine on Necator americanus. golden hamsters infected with about 500 Necator cimeri.covuts larvae for 55 d were administered a single oral dose of 100 mg/kg. 3,6,12 and 15 h after the administration. worms in hamsters were collected and examined morphologically, histologically and histochemically. The results: 1) The number of inactive worms increased from 14.0 to 98.0% 3-15 h after medication; 2) Worms were stiff with their body walls thickened and the internal structures were indistinct. Some worms were disrupted 12-15 h after treatment: 3) The worms showed cuticle swelling and roughening, muscular vacuolation, microvillus desquamation and epithelial cells degeneration and necrosis. The ova at different developmental stages exhibited vacuolation. necrosis or disintegration; 4) The glycogen content. ACP and ATPase activity of the worms decreased markedly 3-6 h after medication and mostly disappeared 12-15 h after medication. It is suggested that the interference of carbohydrate metabolism of Necator americanus by tribendimidine is one of the factors causing the death of the worms.