Phenotypic characterization of Schistosoma mansoni adult worms recovered from undernourished mice: a morphometric study focusing on the reproductive system Caracterização fenotípica de vermes adultos de Schistosoma mansoni recuperados de camundongos desnutridos: estudo morfométrico do sistema reprodutor

A morphometric study focusing on some features of the reproductive system of Schistosoma mansoni adult worms was performed, aiming to complete previously reported data concerning the effects of undernourishment of the host on the parasites. Male worms were significantly affected (p<0.05) regarding the testicular lobes. Key-words: Schistosoma mansoni. Nutritional status. Morphometric study. Phenotypic plasticity. Resumo Foi realizado um estudo morfométrico de alguns elementos do sistema reprodutor de machos e fêmeas de Schistosoma mansoni, objetivando complementar estudo anterior sobre os efeitos da desnutrição do hospedeiro sobre os parasitos. Alterações significativas ocorreram em parasitos machos (p<0,05), em relação aos lobos testiculares. Palavras-chaves: Schistosoma mansoni. Estado nutricional. Estudo morfométrico. Plasticidade fenotípica. 1. Disciplina de Parasitologia do Departamento de Patologia e Laboratórios da Faculdade de Ciências Médicas da Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ. 2. Departamento de Imunologia do Centro de Pesquisa Aggeu Magalhães da Fundação Oswaldo Cruz, Recife, PE. 3. Laboratório de Helmintos Parasitos de Vertebrados do Departamento de Helmintologia do Instituto Oswaldo Cruz da Fundação Oswaldo Cruz,Rio de Janeiro, RJ. Supported by: UERJ, FAPERJ, CNPq This work is part of a Master thesis at Mestrado de Morfologia – Instituto de Biologia – UERJ – RJ, Brazil Address to: Dr. José Roberto Machado e Silva. Disciplina de Parasitologia/FCM/UERJ. R.Prof. Manoel de Abreu 48/5o andar, Vila Isabel, 20551-170 Rio de Janeiro, RJ, Brazil. Tel: 55 21587-6112. e-mail: [email protected] Recebido para publicação em 10/10/2001. Schistosomiasis mansoni and malnutrition are pathologies that can simultaneously occur in developing areas such as Northeastern Brazil4. The difficulty in undertaking longitudinal studies in human populations has justified the development of experimental models. Malnutrition has been considered as a factor able to modify the host-parasite-environment system, aggravating the course of schistosomiasis by breaking the equilibrium in the relationships among the components of this system3. Brightfield, scanning electron microscopy and confocal laser scanning microscopy (CLSM) have been used in morphological studies of Schistosoma mansoni adult worms9 11 12 13 14 15 20. Besides the known effects on the course of the infection, malnutrition of the host leads to a reduction in the worm body length and in the distance between the suckers in males, as well as changes in the reproductive system of male and female worms21. These findings were also confirmed by confocal laser scanning microscopy (CLSM). This paper aims to bring some additional information concerning the effects of the undernourishment of the host on male and female adult Schistosoma mansoni. Swiss Webster mice were percutaneously infected with 80 cercariae (BH strain). Undernourished animals were fed a multideficient and essentially low protein diet (Regional Basic Diet – RBD)5. Well-fed control mice ingested a standard commercial diet (Nuvilab CR-1). Mice were sacrificed 75 days post-infection and worms were recovered by perfusion technique7. All specimens were fixed in 10% formalin, stained with carmine chloride, clarified in methyl salicylate and preserved as whole-mounts. A brightfield microscope linked to software for image analysis (Image Pro Plus – Media Cybernetics) was