Date Published: July 20, 2020
Publisher: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Author(s): Leidelamar Rosário Alves de Oliveira, Andréa de Oliveira Albuquerque, Cícero Igor Simões Moura Silva, Jussara Mathiele Silva, Meyssa Quezado de Figueiredo Cavalcante Casadevall, Orleancio Gomes Ripardo de Azevedo, Vilma Leite de Souza Pires Albuquerque, Paulo Roberto Leitão de Vasconcelos.
To evaluate the neuroprotective effect of L-alanyl-glutamine in a gerbil model of brain ischemia-reperfusion injury based on immunohistochemical quantification of pro-inflammatory and cell activation biomarkers (TNF-α, NF-κB, IL-6 and HO-1).
Male gerbils weighing 100-180 g were pretreated with either 0.75 g/kg L-Ala-Gln (n=18) or 2.0 mL saline (n=18) administered i.v. 30 minutes before the bilateral ligation of the common carotid artery during 15 min and then the ligation was removed. Under anesthesia with urethane, brain tissue was harvested at 0 min (T0), 30 min (T30) and 60 min (T60) after reperfusion. The tissue was embedded in 10% formalin overnight and 4-μm sections were prepared for immunostaining with monoclonal antibodies. Immunostained cells were counted by optical microscopy. The statistical analysis used mean values based on 4 sections.
The pretreatment with L-Ala-Gln animal group 1 demonstrated significantly lower levels of TNF-α, NF-κB and IL-6. On the other hand, the levels of HO-1 were significantly higher, suggesting a protective role in model of brain ischemia-reperfusion injury.
These findings suggest a protective effect of L-Ala-Gln by decreasing levels of TNF-alpha, IL-6 and NF-κB and Increasing levels of HO-1.
Cerebrovascular diseases are currently the third-most important cause of death in several developed and developing countries. The European incidence of cerebral infarction is 1.35-2.2 / 1,000 inhabitants, and 83% of cases are associated to ischemic etiology1. According to the National Institute of Health, cerebrovascular diseases affect about 500,000 people every year in the U.S., with a mortality rate of 20-30% and a similar rate of severe disability2.
The study was conducted in accordance with the International Guiding Principles for Biomedical Research Involving Animals (1990). The study protocol was approved in 2008 by the Research Ethics Committee (CEPA) of Universidade Federal do Ceará (UFC), #127/07. The gerbils were supplied by the experimental animal facility at Centro Universitário Christus and used at the laboratory of experimental surgery (UFC School of Medicine).
In this study, we found immunohistochemical evidence of the protective effect of L-Ala-Gln on the internal pyramidal layer of the parietal area of gerbil brain tissue exposed to ischemia and reperfusion injuries based on the quantification of inflammation and cell activation biomarkers (TNF-α, NF-κB, IL-6 and HO-1). In 2011, Pires and cols. using the same bilateral occlusion protocol of cerebral ischemia/reperfusion demonstrated that precondition with L-Ala-Gln reduced the oxidative stress in cerebral tissue15. Thus, this study evaluates the inflammatory aspect of cerebral ischemia/reperfusion.
Preconditioning with L-Ala-Gln has a potentially protective role against inflammation induced by brain ischemia and reperfusion.