Modulating effect of ionizing radiation on blood cytokines and bone tissue cells at the bone-implant interface

Author(s)

Mariana Raquel da Cruz Vegian

• Document type: Master's Dissertation
• Press: São José dos Campos. 2018-05-21.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Ciência e Tecnologia. São José dos Campos
• Defense date: 2018-05-02
• Advisor: Luana Marotta Reis de Vasconcellos; Gabriela de Fátima Santana Melo

Abstract

Osseointegrated implants are considered effective as a rehabilitative treatment. However, several factors may impair the receptor site, including ionizing radiation. However, the mechanisms by which these events occur have not yet been fully elucidated. The objective of this study was to evaluate the modulating effect of radiotherapy, simulating a total dose of a conventional ionizing radiation treatment for cancer patients, blood cytokine levels and bone remodeling of the interface around the implant. Forty-five rats were submitted to grade V titanium implants in the right femurs. The animals were divided into three groups: a)No Irradiation group (N-Ir): control group with only the implant b) Previous irradiation group (Prev-Ir): implant + irradiation; c) Posterior Irradiation group (Pos-Ir): irradiation + implant. Pos-Ir and Prev-Ir groups were irradiated in 2 fractional stages of 15 Gy. At 3 days, 2 weeks and 7 weeks after the last procedure, 05 animals were randomly euthanized per group. Serum levels of TNF-ɑ, IL-1β and IL-10 were measured from blood collected prior to euthanasia using the enzyme-linked immunosorbent assay (ELISA). The pieces containing the implants were subjected to immunohistochemical labeling using the markers for TRAP and osteocalcin (OC). The ANOVA test was used for statistical analysis and when necessary the Tukey multiple comparison test (p <0.05) was applied. The Pos-Ir group exhibited a statistical difference (p <0.05) with N-Ir and Prev-Ir in TNF-α values at 2 and 7 weeks, whereas Prev-Ir differed statistically (p <0.05) from N-Ir in IL-10 values, in 3 days. The immunohistochemical analysis of the bone-implant interface demonstrated higher values of TRAP and OC in the irradiated groups, with a statistical difference (p <0.05) between the values of TRAP of N-Ir and Pos-Ir in 3 days and between N-Ir and Prev-Ir in all periods, and OC between N-Ir and Pos-Ir in 3 days and between N-Ir and Prev-Ir in 2 weeks. In summary, the results of this study indicated that irradiation altered productions of pro and anti-inflammatory blood cytokines after surgical lesion of implant placement and influenced the expression of proteins involved in bone remodeling. (AU)

• FAPESP's process: 16/19707-5 - Modulator effect of ionizing radiation on cytokines blood and tissue cells bone present at interface bone-implant
• Grantee: Mariana Raquel da Cruz Vegian
• Support Opportunities: Scholarships in Brazil - Master