• Ibraim C Castro, Bruna B Oliveira, Jacek J Slowikowski, Bruna P Coutinho, Francisco Júlio W S Siqueira, Lourrany B Costa, Jesus Emmanuel Sevilleja, Camila A Almeida, Aldo A M Lima, Cirle A Warren, Reinaldo B Oriá, and Richard L Guerrant.
• Center for Global Health, Division of Infectious Diseases and International Health, School of Medicine, University of Virginia, Charlottesville, VA, USA.
• Nutrition. 2012 Jun 1; 28 (6): 678-85.

ObjectiveThis study investigated the role of L-arginine supplementation to undernourished and Cryptosporidium parvum-infected suckling mice.MethodsThe following regimens were initiated on the fourth day of life and injected subcutaneously daily. The C. parvum-infected controls received L-arginine (200 mmol/L) or phosphate buffered saline. The L-arginine-treated mice were grouped to receive NG-nitro-arginine methyl ester (L-NAME) (20 mmol/L) or phosphate buffered saline. The infected mice received orally 10(6) excysted C. parvum oocysts on day 6 and were euthanized on day 14 at the infection peak.ResultsL-arginine improved weight gain compared with the untreated infected controls. L-NAME profoundly impaired body weight gain compared with all other groups. Cryptosporidiosis was associated with ileal crypt hyperplasia, villus blunting, and inflammation. L-arginine improved mucosal histology after the infection. L-NAME abrogated these arginine-induced improvements. The infected control mice showed an intense arginase expression, which was even greater with L-NAME. L-arginine decreased the parasite burden, an effect that was reversed by L-NAME. Cryptosporidium parvum infection increased urine NO(3)(-)/NO(2)(-) concentrations compared with the uninfected controls, which was increased by L-arginine supplementation, an effect that was also reversed by L-NAME.ConclusionThese findings show a protective role of L-arginine during C. parvum infection in undernourished mice, with involvement of arginase I and nitric oxide synthase enzymatic actions.Copyright © 2012 Elsevier Inc. All rights reserved.

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