Efeitos da melatonina sobre a inflamação e o estresse oxidativo tecidual de pacientes submetidos à laparoscopia cirúrgica

• Ano de defesa: 2016
• Autor(a) principal: Volquind, Daniel [UNESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Melatonin; Inflammation; Oxidative stress; Peritoneum; Cholecystectomy laparoscopy; Melatonina; Estresse oxidativo; Peritônio; Colecistectomia laparoscópica
• Link de acesso: http://hdl.handle.net/11449/135878

Melatonin was isolated in 1958 and multiple functions of this molecule have been clarified. The actions on specific receptors of membrane, attached to the G protein-coupled receptors are responsible for the control of circadian and seasonal rhythm cycle, however the activity as free radical oxygen scavenger and other mediators of oxidative metabolism are not mediated by receptors. The generation of EROS is directly linked to cellular damage and tissue ischemia and reperfusion being (I/R), the pathophysiological mechanisms that contribute most to the imbalance between oxidants and antioxidants molecules, resulting in oxidative stress. The peritoneal cavity insufflation with carbon gas promotes I/R causing deleterious outcomes for the patient. In order to study the effects of melatonin on the peritoneal inflammation and oxidative stress and genic expression of the proteins MTNR1A and MTNR1B among patients undergoing surgical laparoscopy who received or not melatonin, 80 patients were randomized into 2 groups of 40 patients each to receive melatonin (GMEL) - 20 mg orally 12 hours before and 1 hour before the procedure, respectively -and 40 patients to receive placebo (GPLA) - 12 hours before and 1 hour before the procedure, respectively. Parietal peritoneum samples were collected 10 minutes after the beginning of the pneumoperitoneum and 3 minutes after the end of it. Tissue morphology was evaluated on histopathological examination of slides stained with hematoxylin-eosin for parameters related to inflammation and through immunohistochemistry analysis for protein expression of MTNR1A and MTNR1B. The presented statistically significant reduction in GMEL intensity of inflammatory variables (IF, LP, HP and ED) when compared with the GPLA (p = 0.001). The genic expression of MTNR1A and MTNR1B proteins show no differences between the groups. The main finding of this study was the reduction in inflammatory variables studied, induced by melatonin. It was observed in the GMEL a decrease in degree of inflammatory infiltrates in peritoneal biopsies. This finding allows us to infer that there was also a decrease in oxidative stress. Exogenous melatonin administration showed no influence on genic expression of MTNR1A and MTNR1B proteins. The present study had as main limitations the study not of inflammatory cytokines and markers involved in oxidative stress. However, the melatonina induced attenuation in inflammatory tissue reactions, observed by histopathological analysis, allows to deduce that the non realization of these analyses little influence at the conclusion of the study. In conclusion, under the conditions employed in this study, the results show that melatonin decreases the peritoneal inflammation, and potentially, the oxidative stress in patients undergoing laparoscopy surgical, as well as mitigate the degree of inflammation, inflammatory cells infiltration, endothelial edema and vascular congestion in the parietal peritoneum of these patients. However, melatonin does not modify the genic expression of MTNR1A and MTNR1B proteins in patients undergoing surgical laparoscopy.