Natália Gomes de Morais1,2, Thacianna Barreto da Costa3, Amanda Lúcia Farias Pedrosa4, Maria Carolina Accioly Brelaz de Castro5, Suênia Cunha da Gonçalves de Albuquerque6, Valéria Rêgo Alves Pereira7, Milena de Paiva Cavalcanti8, Célia Maria Machado Barbosa de Castro9. 1. Health Sciences Center, Federal University of São Francisco Valley (UNIVASF), University Campus, Paulo Afonso, BA, 48608-170, Brazil. morais.ngm@gmail.com. 2. Laboratório de Imunopatologia Keizo Asami da Universidade Federal de Pernambuco (LIKA-UFPE), Av. Prof. Moraes Rego, 1235, Cidade Universitária, Recife, PE, 50670-901, Brazil. morais.ngm@gmail.com. 3. Department of Tropical Medicine, Federal University of Pernambuco (UFPE), University Campus, University Town, Recife, PE, 50670-420, Brazil. 4. Scientific Initiation of the Laboratory of Immunopathology Keizo Asami, Federal University of Pernambuco, University Campus, University Town, Recife, PE, 50670-420, Brazil. 5. Aggeu Magalhães Research Center, Oswaldo Cruz Foundation - CPqAM/FIOCRUZ, Campus UFPE, Recife, Brazil. 6. Biosciences and Biotechnology for Health, Aggeu Magalhães Research Center, Oswaldo Cruz Foundation - CPqAM/FIOCRUZ, Campus UFPE, Recife, Brazil. 7. The Laboratory of Immunogenetics, Aggeu Magalhães Research Center, Oswaldo Cruz Foundation - CPqAM/FIOCRUZ, Campus UFPE, Recife, Brazil. 8. The Laboratory of Immunoparasitology, Aggeu Magalhães Research Center, Oswaldo Cruz Foundation - CPqAM/FIOCRUZ, Campus UFPE, Recife, Brazil. 9. Department of Tropical Medicine, Health Sciences Center, Federal University of Pernambuco, University Campus, University Town, Recife, PE, 50670-420, Brazil.
Abstract
OBJECTIVE: Evaluate the effects of neonatal malnutrition on the microbicidal response and viability of in vitro macrophages infected with Staphylococcus aureus sensitive/resistant to methicillin. METHODS: Male Wistar rats (n = 24) were divided into two distinct groups: nourished (rats breast-fed by mothers undergoing diet with 17% casein) and malnourished (rats breast-fed by mothers undergoing diet with 8% casein). Macrophages were recovered after surgical tracheostomy procedure by collecting bronchoalveolar lavage. Four systems were established: negative control, composed only by phagocytes; positive control, macrophages plus lipopolysaccharide; and two test systems, macrophages plus Staphylococcus aureus sensitive and resistant to methicillin. Plates were incubated at 37 °C for 24 h. After this period, tests for the analysis of cell viability and microbicidal response were performed. In the statistical analysis, the Student's t and ANOVA tests were used, accepting p < 0.05. RESULTS: The neonatal malnutrition impaired the animals' body weight. There was a lower expression of the inducible nitric oxide enzyme (iNOS), nitric oxide production, and viability of macrophages infected with methicillin-resistant Staphylococcus aureus. However, increased production of superoxide anion in the malnourished group was detected. CONCLUSION: Neonatal malnutrition focusing on critical periods of development promoted lower expression of iNOS, nitric oxide production, cell viability, and exacerbated reactive oxygen species production. The high levels of reactive oxygen species may favor the onset of serious and systemic infections with fatal outcome if associated with methicillin-resistant Staphylococcus aureus.
OBJECTIVE: Evaluate the effects of neonatal malnutrition on the microbicidal response and viability of in vitro macrophages infected with Staphylococcus aureus sensitive/resistant to methicillin. METHODS: Male Wistar rats (n = 24) were divided into two distinct groups: nourished (rats breast-fed by mothers undergoing diet with 17% casein) and malnourished (rats breast-fed by mothers undergoing diet with 8% casein). Macrophages were recovered after surgical tracheostomy procedure by collecting bronchoalveolar lavage. Four systems were established: negative control, composed only by phagocytes; positive control, macrophages plus lipopolysaccharide; and two test systems, macrophages plus Staphylococcus aureus sensitive and resistant to methicillin. Plates were incubated at 37 °C for 24 h. After this period, tests for the analysis of cell viability and microbicidal response were performed. In the statistical analysis, the Student's t and ANOVA tests were used, accepting p < 0.05. RESULTS: The neonatal malnutrition impaired the animals' body weight. There was a lower expression of the inducible nitric oxide enzyme (iNOS), nitric oxide production, and viability of macrophages infected with methicillin-resistant Staphylococcus aureus. However, increased production of superoxide anion in the malnourished group was detected. CONCLUSION:Neonatal malnutrition focusing on critical periods of development promoted lower expression of iNOS, nitric oxide production, cell viability, and exacerbated reactive oxygen species production. The high levels of reactive oxygen species may favor the onset of serious and systemic infections with fatal outcome if associated with methicillin-resistant Staphylococcus aureus.
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Index terms: malnutrition; Macrophages; Methicillin; Staphylococcus aureus