Impact of lycopene on bone resorption induced by periodontitis in rat molars

• Grant number: 24/01838-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2024
• End date: May 31, 2025
• Field of knowledge: Biological Sciences - Morphology - Histology
• Principal Investigator: Paulo Sergio Cerri
• Grantee: Maria Eduarda Fernandes Mingatto
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

Periodontitis is an immunoinflammatory disease characterized by recruitment of immune system cells that release mediators, such as tumour necrosis factor-alpha (TNF-±), interleukin-1² (IL-1²), IL-6 and matrix metalloproteinases. These cytokines promote degradation of extracellular matrix components as well as osteoclast formation and activity, culminating in the bone loss. Therefore, the modulation of the immunoinflammatory response may be a complementary approach in the treatment of periodontitis. Lycopene, a carotenoid hydrocarbon, has anti-inflammatory and antioxidant effects. Thus, it is possible that lycopene may reduce the damage caused by the progression of periodontitis. The aim of this study will be to evaluate whether the systemic administration of lycopene interferes in with number of macrophages and whether the F4/80-immunopositive macrophages would be involved with RANKL and OPG immunoexpression. 54 Holtzman rats will be randomly distributed into 3 groups: 1) Control Group (CG; healthy rats), 2) PG (rats with periodontitis), 3) PLG (rats with periodontitis and treated with lycopene). Periodontitis will be induced with the insertion of a cotton thread in the cervical colon of the upper 1st molars. In the periodontitis -induction day, the rats will receive 20 mg/kg body weight of lycopene diluted in corn oil by gavage for 7, 35 and 70 days. PG rats will receive the same volume of corn oil by gavage. After 7, 35 and 70 days, the maxilla fragments will be fixed in formaldehyde (pH 7.2), decalcified in 7% EDTA and then processed for paraffin embedding. From each maxilla, non-serial sagittal sections will be stained Masson's trichrome for morphological analysis and to estimate the bone area of the interradicular alveolar process. To evaluate whether lycopene reduces the alveolar bone loss, the number of osteoclasts in the alveolar surface will be computed in the sections subjected to the tartrate-resistant acid phosphatase (TRAP), used as osteoclast marker. In the TRAP-stained sections, the bone surface in close juxtaposition to the osteoclast will be also measured. The number of macrophage will be computed in the sections subjected to the immunohistochemistry for F4/80 detection. The immunohistochemical reactions anti-RANKL and anti-OPG will be performed to evaluate whether the lycopene interferes in the signalling pathways involved with osteoclast formation. The data will be statically analysed in the GraphPad Prism 8.4.3 program and will be submitted to ANOVA and Tukey test (pd0.05).