INFLUENCE OF POLYSTYRENE MICROPLASTIC ON DEVELOPMENT OF OSTEOPOROSIS - ANALYSIS IN WISTAR RATS

• Grant number: 24/09312-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: September 01, 2025
• End date: August 31, 2028
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Rodrigo Bueno de Oliveira
• Grantee: Lauter Eston Pelepenko Teixeira
• Host Institution: Faculdade de Ciências Médicas (FCM). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Introduction: osteoporosis is a disease characterized by a decrease in the mineral density of bones and this condition makes them more fragile and susceptible to fractures. Although this pathology is relatively well understood, there is a gap in the literature when referring to the influence of microplastics (MPs) on the development of osteoporosis. Aim: analyse the influence of polystyrene MPs on the development of osteoporosis. Material and methods: for this purpose, an animal model (Wistar rats) will be used for testing in osteoporosis conditions using ovariectomized animals in comparison with sham control animals. Fluoresbrite® measuring 0.5 µm in diameter of polystyrene MPs (#18339-10) will be obtained and characterized prior to administration to the animal model by different analytical techniques (scanning electron microscope, FTIR spectroscopy, fluorescence and Raman). The animals will be divided into sham, ovariectomized and treated with polystyrene, and with a known MPs internalization inhibitor, the sucrose. After daily oral gavage of polystyrene (0.5 mg/day) for 28 days, euthanasia will be performed (on day 45 of the experiment) and femurs will be analysed for potential worsening of osteoporosis using histomorphometry (double labelled with tetracycline) stained with toluidine blue and immunohistochemistry. Furthermore, femoral fracture resistance will be analysed by mechanical flexion strength test and the accumulation of polystyrene will also be investigated using analytical techniques. The tibias will be lysed and subjected to protein analysis from their lysates using the Multiplex/Luminex system and by Raman and fluorescence spectroscopy for polystyrene detection. Additionally, blood serum obtained by centrifuged intra-cardiac collection will be analysed for markers: CTx (beta-crosslap; bone turnover), TRAP 5b, alkaline phosphatase-bone fraction, parathormone, sclerostin, Dickoppf-1; and chemical elements calcium, phosphorus and magnesium. The data obtained will be tabulated and analysed to verify whether they meet the distribution assumptions (Shapiro-Wilk) for a parametric analysis or not and, subsequently, statistically compared (p < 0.05) according to their distribution (ANOVA or Kruskal- Wallis). Hypothesis: the investigated hypothesis is that the ingestion of polystyrene MPs does not worsen the development of osteoporosis. Dissemination: publication will be sought in a scientific article and disseminate results at national and international events. (AU)