Effects of intrauterine exposure to nicotine on ovarian follicular reserve in adult rats

• Grant number: 24/02422-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2024
• End date: May 31, 2025
• Field of knowledge: Biological Sciences - Morphology - Embryology
• Principal Investigator: Camila Cicconi Paccola
• Grantee: Isabela Dinis dos Santos
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

Studies show changes in the fertility of offspring exposed to nicotine, the main component of cigarettes. The effects can occur during pre- and post-natal development, such as changes in the onset of puberty and variations in the levels of sex hormones, both in males and females, besides irregularities in reproductive cycles and anticipation of menopause in women. Therefore, this work aims to verify the effects of exposure to nicotine, during the intrauterine phase and during breastfeeding, on the ovarian follicular reserve of adult rats. For this, pregnant rats will receive an osmotic pump containing 2mg/kg/day of nicotine from the first day of pregnancy, in order to expose the offspring throughout the pregnancy. This pump will be refilled on the 1st day after the birth of the offspring, ensuring exposure to nicotine through breastfeeding. The female offspring will be euthanized on the 90th postnatal day, when the ovaries will be collected. One ovary from each rat will be frozen and subjected to analysis of proliferation (PCNA) and cell death (Caspase-3) and hormone receptors (FSH and LH), by western-blotting. The other ovary will be fixed and subjected to immunohistochemical marking of oocytes using an oocyte-specific antibody (VASA or MVH), aiming to count the oocytes/follicles present in the ovaries.