Diferenças sexuais na reatividade vascular da aorta após tratamento com glucosamina em ratos wistar

Abstract

Post-translational modifications (MPTs) occur throughout the body and are essential for protein function. The reversible addition or removal of chemical groups in a protein implies changes in its activity or location. Among these MPTs, O-glycosylation with Nacetylglucosamine (O-GlcNAc) stands out. Several proteins are targets of O-GlcNAc, including proteins responsible for regulating vascular tone. It is also known that males and females have vascular differences associated with hormonal activity in the vessels. Therefore, the aim of this study was to evaluate whether chronic treatment with glucosamine modulates the vascular response in the aorta of males and females differently. Male Wistar rats (13-15 wk; 350-400g) and females (13-15 wk; 300-350g) were randomly divided into the following groups a) vehicle males, b) glucosamine males, c) vehicle females and d) females glucosamine, where the groups treated with glucosamine received a daily dose of 300 mg / kg for 21 days (ip, n = 15) and the control group received saline daily for 21 days (ip, n = 15). At the end of treatment, blood pressure measurement and oral glucose tolerance test were performed. Concentration-response curves (CRC) for acetylcholine (ACh), phenylephrine (PHE) and sodium nitroprusside [SNP (in the presence of L-NAME; 100 µM, 30 min.)] were performed in the aorta. Glucosamine treatment for 21 days did not alter systolic blood pressure or glucose tolerance in any group. However, CRC for PHE demonstrated a decrease in contractile response in the male group treated with glucosamine compared to the control group [Emax (%) 61.43 ± 3.76 vs. 88.20 ± 2.14, respectively]. Endothelium-dependent relaxation was greater in the male glucosamine group compared to the control group [pD2 (%) 7.63 ± 0.09 vs. 7.12 ± 0.11, respectively] without changing the maximum response. In females there were no significant changes for PHE or Ach. Endothelium-independent relaxation was also not altered in any group. The data found suggest that treatment with glucosamine for 21 days results in vascular dysfunction via decreased contractile response in the aorta of males, while females have protection against glucosamine.