Banca de DEFESA: MARIA VANESSA DA SILVA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : MARIA VANESSA DA SILVA
DATE: 25/02/2026
TIME: 08:00
LOCAL: Sala 205 do Departamento de Biologia
TITLE:

INVESTIGATION OF THE PROTECTIVE EFFECT OF MELATONIN ON THE FETAL ORGANOGENESIS PERIOD IN RATS EXPOSED TO CHRONIC ALCOHOL CONSUMPTION

KEY WORDS:

Morphogenesis; oxidative stress; ethanol; antioxidant; pregnancy

PAGES: 105
BIG AREA: Ciências Biológicas
AREA: Morfologia
SUBÁREA: Histologia
SUMMARY:

Alcohol consumption during pregnancy can cause a wide range of cognitive, behavioral, and emotional deficits, as well as promote congenital anomalies. This xenobiotic can easily cross the placenta and reach the fetus, leading to the disruption of maternal metabolic pathways and impairing the development of vital organs such as the brain, liver, and kidneys, causing neurodegeneration, hepatic fibrosis, and a reduction in the number of nephrons, respectively. Melatonin has demonstrated several therapeutic benefits, and studies support its effectiveness in preventing brain, liver, and kidney damage. Although there is significant evidence on the harmful effects of alcohol consumption during pregnancy on fetal health, there are still gaps in knowledge about which specific period of organogenesis is most vulnerable to the effects of this substance. Thus, this work proposes to evaluate which period of organogenesis of the brain, liver, and kidneys of rat offspring is most affected by alcohol consumption during gestation, and whether melatonin is able to prevent these effects. For this study, 30 virgin, 90-day-old albino Wistar rats weighing approximately 250g were used, obtained from the Animal Facility of the Department of Animal Morphology and Physiology, Federal Rural University of Pernambuco (UFRPE). The animals were distributed into six experimental groups: Control - rats without alcohol exposure and euthanized at periods E15 and E19; Alcohol - rats subjected to chronic alcohol consumption and euthanized at periods E15 and E19; Alcohol + Melatonin - rats subjected to chronic alcohol consumption and euthanized at periods E15 and E19. All groups were euthanized on the 15th and 19th day of gestation, respectively. Alcohol was administered by intragastric gavage at a dose of 3 g/kg. Melatonin was administered by daily injections at a dosage of 0.8 mg/kg. Regarding the brain, in the analysis of weights and lengths of E15 and E19 in the alcohol group, a significant reduction in the weight of the dams, and the weight and length of the fetuses, was observed compared to the control and alcohol + melatonin groups. Our study found structural disorganization of the cerebral mesenchyme, which can be indicated by alterations in the estimated external, borderline, and internal density of the neuroepithelium and by the decreased volume of the telencephalon in the alcohol group in E15 and E19. We also observed a decrease in the thickness of the neuroepithelium in E15, persisting in E19, in the alcohol group, compared to the other groups. Furthermore, in E15, an incorrect structure of the molecular layer of the telencephalon was observed, and in E19, less development of the telencephalon ventricles was observed in the alcohol group compared to the other groups. Our findings indicate increased levels of pro-inflammatory cytokines, both IL-6 and TNFα, from E15 to E19 in the alcohol group when compared to the other groups. An increase in apoptotic cell staining was also observed in the alcohol group at E15 and E19, compared to the other experimental groups. For PCNA staining, the alcohol group showed lower cell proliferation at E15 and E19 compared to the other groups. Regarding liver results, fetuses from the control and alcohol + melatonin groups, at E15, presented quite voluminous hepatic lobules with centrilobular veins, sinusoids, hepatoblasts, hematopoietic cells, and some hepatocytes. The livers from the alcohol group at E15 showed less developed hepatic lobules compared to the other groups, with centrilobular veins surrounded only by hepatoblasts. Period E19 revealed that in the control and alcohol + melatonin groups, hepatoblasts and hepatocytes still coexisted. In the alcohol group, histological characteristics similar to those found in the livers of fetuses from the control and alcohol + melatonin groups in period E15 were evident. Immunohistochemical analysis of the liver in both periods revealed similar assays in the control and alcohol + melatonin groups, with strong staining for IL6 and TNFα. Furthermore, strong cell proliferation and a reduction in the apoptotic index were recorded in the livers of fetuses when compared to the alcohol group. Regarding the kidneys, the results indicated that in period E15, the control and alcohol + melatonin groups showed the presence of developing glomeruli, ellipsoid vesicles near the surface, with undifferentiated epithelial cells surrounded by mesenchymal tissue. In the alcohol group, branching in the mesenchymal tissue for the formation of renal glomeruli was observed. In period E19, the cortical and medullary regions were well defined. In fetuses from the control and alcohol + melatonin groups, the beginning of the formation of primitive renal glomeruli and the first renal corpuscles was observed. In the alcohol group, the kidneys presented ellipsoid vesicles near the renal surface, suggesting glomerular primordia. Immunohistochemical analysis of the liver in both periods revealed similar assays in the control and alcohol + melatonin groups, with strong staining for IL-6 and TNF-α. Meanwhile, the kidney showed weak staining for these same parameters. Furthermore, strong cell proliferation and a reduction in the apoptotic index were recorded in the liver and kidneys of the fetuses when compared to the alcohol group. Therefore, it is concluded that melatonin presents itself as a molecule with high protective potential on neurogenesis, nephrogenesis, and hepatogenesis, regulating the expression of the pro-inflammatory cytokines IL-6 and TNF-α, apoptosis, and PCNA, against the alterations caused by chronic alcohol consumption during fetal organogenesis.

COMMITTEE MEMBERS:
Presidente - VALERIA WANDERLEY TEIXEIRA
Externo ao Programa - 1342787 - ANDERSON RODRIGUES BALBINO DE LIMA - UFRPEExterna à Instituição - FERNANDA DAS CHAGAS ÂNGELO MENDES TENÓRIO - UFPE
Externa à Instituição - ISMAELA MARIA FERREIRA DE MELO
Externo à Instituição - JAIURTE GOMES MARTINS DA SILVA - UFAL