title: Effects of nutritional supplementation with l-arginine on repair of injuries due to muscle strain: experimental study on rats.
abstract: OBJECTIVE
  To evaluate the influence of oral supplementation with arginine on regeneration of injuries due to straining of the anterior tibial muscle of rats.
  
  
  METHODS
  Twenty-four Wistar rats of weight 492.5 ± 50.45 g were used. Injuries were induced through straining the anterior tibial muscles. The rats were separated into three groups of eight rats each. In the untreated group (UTG), after induction of injuries, the rats were observed for 24 h. In the simulation group (SG) and the arginine group (AG) respectively, the rats received isotonic saline solution and arginine solution via direct gavage, over a seven-day period. At the end of the period, blood samples were collected for serum evaluations of creatine kinase (CK), lactic dehydrogenase (LDH), aspartate aminotransferase (AST) and C-reactive protein (CRP). The right and left anterior tibial muscles were resected for histopathological evaluations on the muscle injuries, investigating edema, hemorrhage and disorganization or morphometric alteration of the muscle fibers. The tissue repair was investigated in terms of proliferation of adipose tissue, angiogenesis and collagen fibers. The ANOVA and Student's t methods were used and p ≤ 0.05 was taken to be statistically significant.
  
  
  RESULTS
  In the serum evaluations, the AG showed lower CK assay values and higher AST values. In the histopathological evaluation, the UTG presented edema and hemorrhage compatible with injuries due to strain; the SG presented edema and hemorrhage with proliferation of adipose tissue and collagen fibers; and the AG presented not only the findings of the SG but also, especially, intense angiogenesis.
  
  
  CONCLUSIONS
  Oral supplementation with arginine did not cause any significant metabolic alterations that would contraindicate its use and it induced angiogenesis during the repair of muscles injured due to strain.
authors.affiliation: Department of Orthopedics and Traumatology, Hospital Angelina Caron, Campina Grande do Sul, PR, Brazil.
authors.forename: Lauren Izabel Medeiros
authors.initials: LI
authors.lastname: Couto
authors.affiliation: Department of Orthopedics and Traumatology, Hospital Angelina Caron, Campina Grande do Sul, PR, Brazil.
authors.forename: William Luiz
authors.initials: WL
authors.lastname: Wuicik
authors.affiliation: Department of Orthopedics and Traumatology, Hospital Angelina Caron, Campina Grande do Sul, PR, Brazil.
authors.forename: Ivan
authors.initials: I
authors.lastname: Kuhn
authors.affiliation: Department of Orthopedics and Traumatology, Hospital Angelina Caron, Campina Grande do Sul, PR, Brazil.
authors.forename: Juan Rodolfo Vilela
authors.initials: JR
authors.lastname: Capriotti
authors.affiliation: Department of Orthopedics and Traumatology, Hospital Angelina Caron, Campina Grande do Sul, PR, Brazil.
authors.forename: João Carlos
authors.initials: JC
authors.lastname: Repka
keywords: Arginine; Muscles/injury; Rats; Regeneration