Daily melatonin administration improves osseointegration in pinealectomized rats

Abstract

The hypothesis of this study was that the peri-implant bone healing of the group of pinealectomized rats would differ from the control group. The samples were subjected to immunohistochemical, microtomographic (total porosity and connectivity density), and fluorochrome (mineralized surface) analyses. Objectives The goal of this study was to investigate the cellular changes and bone remodeling dynamics along the bone/implant interface in pinealectomized rats.Material and Methods The total of 18 adult male rats (Rattus norvegicus albinus, Wistar) was divided into three groups (n=6): control (CO), pinealectomized without melatonin (PNX) and pinealectomized with melatonin (PNXm). All animals were submitted to the first surgery (pinealectomy), except the CO group. Thirty days after the pinealectomy without melatonin, the second surgery was conducted, in which all animals received an implant in each tibia (36 titanium implants with surface treatment were installed – Implalife® São Paulo, SP, Brazil). By gavage, the rats of the PNX group received the vehicle solution, and the procedure.Results Immunohistochemical analysis for runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteopontin (OP) and osteocalcin (OC) showed that the bone repair process in the PNXm group was similar to that of the CO group, whereas the PNX group showed a delay. The microtomographic parameters of total porosity [Po(tot)] and bone surface (BS) showed no statistically significant differences, whereas for the connective density (Conn.Dn) a statistical difference was found between the CO and PNXm groups. Fluorochrome analysis of the active mineralized surface showed statistically significant difference between the CO and PNX and between the CO and PNXm groups.Conclusion The absence of the pineal gland impaired the bone repair process during osseointegration, however the daily melatonin replacement was able to restore this response.

Comparison between Plasma Electrolytic Oxidation Coating and Sandblasted Acid-Etched Surface Treatment: Histometric, Tomographic, and Expression Levels of Osteoclastogenic Factors in Osteoporotic Rats

“…The sample size was determined according to the previously published manuscript [38], in which six animals per group were used, with a normal distribution. Thus, eight animals per group (n = 8) were elected, in compliance with the ethical guidelines for animal researches that expect losses of at least 20% of the sample.…”

Is the Bacterial Cellulose Membrane Feasible for Osteopromotive Property?

“…The immunohistochemical reactions were evaluated by assigning scores based on a semi-quantitative analysis [ 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. The scores were assigned as null (0), mild (1), moderate (2), and intense (3).…”

β-catenin and Its Relation to Alveolar Bone Mechanical Deformation – A Study Conducted in Rats With Tooth Extraction

“…Animal models provide relevant information about a variety of disorders in dentistry. The rat model has been widely used for studies in dentistry, including those which involve periodontal diseases, alveolar bone healing, tooth movement, osteogenesis, osseointegration, use of biomaterials, and altered occlusal loadings, for example (Okamoto and de Russo, 1973;Shimomoto et al, 2007;Walker et al, 2008;Wan et al, 2012;Xu et al, 2016;Zeng et al, 2016;Koutouzis et al, 2017;Lee et al, 2017;Hassumi et al, 2018;Palin et al, 2018;Uslu et al, 2018;Wang et al, 2018). Besides that, tooth extraction, inclosing incisor extraction, has been considered as a classical model of preclinical studies and has been applied in many studies with different aims in the last years (Avivi-Arber et al, 2010;Shoji et al, 2010;Boonyagul et al, 2014;Curra et al, 2016;Hassumi et al, 2018;de Oliveira Puttini et al, 2019).…”