Efeito da melatonina na maturação in vitro sobre a expressão gênica e a qualidade de oócitos bovinos sob choque térmico
Year: 2017
Type: dissertation
Abstract: The objective of this study was to evaluate the effect of melatonin addition to the in \nvitro maturation (IVM) medium of bovine oocytes subjected to heat shock on \nquality and expression of specific genes. Ovarian follicles from 3 to 8 mm of \ndiameter, were aspirated from ovaries obtained in a slaughterhouse. Oocytes were \nmatured under heat shock in IVM medium with melatonin, in the following \nconcentrations: 0; 10 \n12 \n; 10 \n-9 \n; 10 \n-6 \ne 10 \n-3 \nM. In the positive control, oocytes were \nmatured in the absence of melatonin (NS) on conventional condition. Three to six \nbatteries were performed for each analysis. The randomized block design was \nutilized, being the blocks formed by the batteries. Maturation and apoptosis rate, \nreactive oxygen species (ROS) and mitochondrial activity were analyzed by \ngeneralized linear models through the GLIMIMIX procedure (SAS \n® \n). To the gene \nexpression analysis, the treatment NS was used as a calibrator and the primer \nefficiency was calculated through the program LinRegPCR, with the results being \nanalyzed by the REST \n® \nsoftware. Maturation rate did not differ between oocytes \nmatured under heat shock with different melatonin concentration and did not differ \nbetween oocytes from treatments 0 M of melatonin under heat shock and 0 M of \nmelatonin under conventional conditions. The concentrations 10 \n-3 \nand 10 \n-9 \nM of \nmelatonin reduced the maturation rate in comparison to NS. Melatonin did not \ninfluence the apoptosis rate. Apoptosis rate from NS group was lower than \nobserved on group 0 M, but it did not differ from the rate observed in the treatment \n10 \n-3 \n. ROS production was lower in the treatments 10 \n-9 \n, 10 \n-6 \n, and 10 \n-3 \nM and greater \nin the treatments 0 and 10 \n-12 \n. Mitochondrial activity of oocytes matured at 10 \n-12 \n, 10 \n-9 \n, and 10 \n-6 \nM of melatonin did not differ from the one observed in oocytes of \ntreatment NS. Oocytes from group 0 M presented greater mitochondrial activity \ncompared to oocytes from group NS. There was subexpression of genes c-MOS in \nthe treatments 10 \n-9 \nand 10 \n-12 \nM of melatonin and of MAPK in the treatment 10 \n-12 \nM. The treatments 10 \n-3 \n; 10 \n-6 \nand 10 \n-9 \nM of melatonin presented subexpression of \nthe gene GDF-9. Genes ZAR1 and HSP40 were not affected by the melatonin \naddition to the IVM medium or by the heat shock. Concluding, melatonin is able to \nprotect oocytes from the damage caused by heat shock, being the concentration 10 \n-6 the most efficient.
Author: Paula, Fabiane Angélica de Paiva
Language: English
Subfield: Reproductive Medicine
Field: Medicine
Domain: Health Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W7056152684