Efeitos da suplementação com melatonina na remodelação óssea alveolar em ratos pinealectomizados com doença periodontal.
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Data
2018-06-11
Autores
Marani, Fernando [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Pesquisas têm sido realizadas para investigar a relação entre inflamações crônicas na cavidade oral e efeitos deletérios em diversos sistemas do organismo. A doença periodontal (DP) caracterizada como uma infecção e inflamação oral está associada à produção de citocinas inflamatórias, tais como fator de necrose tumoral-alfa (TNF-α) e interleucina-6 (IL-6), as quais aumentam a expressão dos osteoclastos, levando a um aumento da reabsorção óssea alveolar. Além da influência destas citocinas na perda óssea alveolar, evidências científicas apontam que a falta do hormônio melatonina também pode contribuir para uma maior reabsorção óssea. A melatonina é um poderoso regulador da homeostase de diversos tecidos. Assim, este hormônio pode ter um importante papel na proteção de tecidos lesionados, podendo ser visto, como um possível coadjuvante no tratamento de doenças da cavidade oral devido principalmente sua ação antioxidante e imunomoduladora. Portanto, o objetivo deste estudo foi verificar o efeito da suplementação da melatonina na reabsorção óssea alveolar em ratos com doença periodontal e pinealectomizados (PNX), avaliando: 1) concentrações plasmáticas de TNF-α e IL-6 pelo método de ELISA; 2) marcadores ósseos como a fosfatase ácida resistente ao tartarato (TRAP) e Osteocalcina (OCN) por meio de técnica imunoistoquímica; 3) histomorfometria da região comprometida pela DP pelo escaneamento no microtomógrafo em 3D (Micro-CT) (modelo 1172 SkyScan®). Para tanto, oitenta (80) ratos Wistar machos com 40 dias de idade foram distribuídos aleatoriamente em 8 grupos (n=10): controle (CN), doença periodontal (DP), pinealectomizados (PNX), pinealectomizados com doença periodontal (PNXDP), controle com melatonina (CNMEL), doença periodontal com melatonina (DPMEL), pinealectomizados com melatonina (PNXMEL) e pinealectomizados com doença periodontal e com melatonina (PNXDPMEL). A DP foi induzida após 20 dias da pinealectomia por ligadura com fio de seda ao redor dos primeiros molares mandibulares. Após 28 dias da indução da DP, os experimentos foram realizados. A análise estatística foi realizada por análise de variância Three-way (ANOVA), seguida pelo teste de Tukey e para as análises de imunoistoquímicas pelo teste estatístico não paramétrico de Kruskal Wallis. O nível de significância adotado foi de 5% (alfa=5%). Os resultados evidenciaram um aumento de mediador pró-inflamatório TNF-α tanto nos animais com DP como PNX. Apenas os grupos com DP (DP e PNXDP) apresentaram maior reabsorção óssea alveolar devido uma maior atividade dos osteoclastos comparado a dos osteoblastos evidenciado pelo aumento do marcador de reabsorção, fosfatase ácida resistente ao tartarato (TRAP), e diminuição do marcador de formação, osteocalcina (OCN) como também pelos resultados histomorfométricos. Por outro lado, os animais tratados com melatonina não apresentaram alteração na concentração plasmática de TNF-α e perda óssea alveolar. Com base nos resultados do presente estudo, verificou-se que os animais pinealectomizados e com DP apresentaram elevada concentração de TNF-α, mas a perda óssea alveolar ocorreu apenas nos animais com DP. A pinealectomia não promoveu alteração óssea como também não agravou esse parâmetro em animais com DP. A suplementação com melatonina promoveu diminuição de TNF-α nos animais pinealectomizados e com DP. Em todos os grupos com DP a melatonina protegeu-os da reabsorção óssea alveolar. Portanto, estes resultados demonstram que a melatonina é eficiente no controle tanto da reabsorção óssea alveolar como da concentração plasmática de TNF-α em ratos com DP e PNX, demonstrando sua importância local e sistêmica.
ABSTRACT Researches has been conducted to investigate the relationship between chronic inflammation in the oral cavity and deleterious effects on various systems of the body. Periodontal disease (PD) characterized as an infection and oral inflammation is associated with the production of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), which increase the expression of osteoclasts, leading to an increase in alveolar bone resorption. In addition to the influence of these cytokines on alveolar bone loss, scientific evidence indicates that the lack of the hormone melatonin may also contribute to a greater bone resorption. Melatonin is a powerful regulator of homeostasis of various tissues. Thus, this hormone may have an important role in the protection of injured tissues, and can be seen as a possible adjuvant in the treatment of diseases of the oral cavity mainly due to its antioxidant and immunomodulatory action. Therefore, the objective of this study was to verify the effect of melatonin supplementation on alveolar bone resorption in rats with periodontal disease and pinealectomized (PNX), evaluating: 1) plasma concentrations of TNF-α and IL-6 by the ELISA method; 2) bone markers such as tartrate resistant acid phosphatase (TRAP) and Osteocalcin (OCN) by immunohistochemical technique; 3) histomorphometry of the region compromised by PD by scanning in the microtomograph in 3D (Micro-CT) (model 1172 SkyScan®). Therefore, eighty (80) Wistar male rats of 40 days old were randomly distributed into 8 groups (n= 10): control (CN), periodontal disease (PD), pinealectomized (PNX) pinealectomized with periodontal disease (PNXPD), control with melatonin (CNMEL), periodontal disease with melatonin (PDMEL) pinealectomized with melatonin (PNXMEL) and pinealectomized with periodontal disease and melatonin (PNXPDMEL). PD was induced after 20 days of pinealectomy by ligation with silk thread around the first mandibular molars. After 28 days of induction of DP, the experiments were performed. Statistical analysis was performed by Three-way analysis of variance (ANOVA), followed by the Tukey's test and for the immunohistochemical analyzes by the non-parametric statistical test of Kruskal Wallis. The level of significance was 5% (alpha = 5%). The results evidenced an increase of proinflammatory mediator TNF-α in both PD and PNX animals. Only the groups with PD (PD and PNXPD) presented greater alveolar bone resorption due to a higer activity of the osteoclasts compared to the osteoblasts evidenced by the increase of the resorption marker, tartrate resistant acid phosphatase (TRAP), and decrease of the formation marker osteocalcin (OCN) as well as histomorphometric results. On the other hand, in animals treated with melatonin there was no change in plasma TNF-α concentration and alveolar bone loss. Based on the results of the present study, pinealectomized and PD animals showed high concentration of TNF-α, but alveolar bone loss occurred only in animals with PD. Pinealectomy did not promote bone alteration, nor did it aggravate this parameter in animals with PD. Supplementation with melatonin promoted decreased TNF-α in pinealectomized and PD animals. In all groups with PD, melatonin protected them from alveolar bone resorption. Therefore, these results demonstrate that melatonin is efficient in controlling both alveolar bone resorption and plasma TNF-α concentration in rats with PD and PNX, demonstrating its local and systemic importance.
ABSTRACT Researches has been conducted to investigate the relationship between chronic inflammation in the oral cavity and deleterious effects on various systems of the body. Periodontal disease (PD) characterized as an infection and oral inflammation is associated with the production of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), which increase the expression of osteoclasts, leading to an increase in alveolar bone resorption. In addition to the influence of these cytokines on alveolar bone loss, scientific evidence indicates that the lack of the hormone melatonin may also contribute to a greater bone resorption. Melatonin is a powerful regulator of homeostasis of various tissues. Thus, this hormone may have an important role in the protection of injured tissues, and can be seen as a possible adjuvant in the treatment of diseases of the oral cavity mainly due to its antioxidant and immunomodulatory action. Therefore, the objective of this study was to verify the effect of melatonin supplementation on alveolar bone resorption in rats with periodontal disease and pinealectomized (PNX), evaluating: 1) plasma concentrations of TNF-α and IL-6 by the ELISA method; 2) bone markers such as tartrate resistant acid phosphatase (TRAP) and Osteocalcin (OCN) by immunohistochemical technique; 3) histomorphometry of the region compromised by PD by scanning in the microtomograph in 3D (Micro-CT) (model 1172 SkyScan®). Therefore, eighty (80) Wistar male rats of 40 days old were randomly distributed into 8 groups (n= 10): control (CN), periodontal disease (PD), pinealectomized (PNX) pinealectomized with periodontal disease (PNXPD), control with melatonin (CNMEL), periodontal disease with melatonin (PDMEL) pinealectomized with melatonin (PNXMEL) and pinealectomized with periodontal disease and melatonin (PNXPDMEL). PD was induced after 20 days of pinealectomy by ligation with silk thread around the first mandibular molars. After 28 days of induction of DP, the experiments were performed. Statistical analysis was performed by Three-way analysis of variance (ANOVA), followed by the Tukey's test and for the immunohistochemical analyzes by the non-parametric statistical test of Kruskal Wallis. The level of significance was 5% (alpha = 5%). The results evidenced an increase of proinflammatory mediator TNF-α in both PD and PNX animals. Only the groups with PD (PD and PNXPD) presented greater alveolar bone resorption due to a higer activity of the osteoclasts compared to the osteoblasts evidenced by the increase of the resorption marker, tartrate resistant acid phosphatase (TRAP), and decrease of the formation marker osteocalcin (OCN) as well as histomorphometric results. On the other hand, in animals treated with melatonin there was no change in plasma TNF-α concentration and alveolar bone loss. Based on the results of the present study, pinealectomized and PD animals showed high concentration of TNF-α, but alveolar bone loss occurred only in animals with PD. Pinealectomy did not promote bone alteration, nor did it aggravate this parameter in animals with PD. Supplementation with melatonin promoted decreased TNF-α in pinealectomized and PD animals. In all groups with PD, melatonin protected them from alveolar bone resorption. Therefore, these results demonstrate that melatonin is efficient in controlling both alveolar bone resorption and plasma TNF-α concentration in rats with PD and PNX, demonstrating its local and systemic importance.
Descrição
Palavras-chave
Melatonina, Inflamação, Melatonin, Inflammation, Pineal gland, Glândula pineal, Doênças periodontais, Reabsorção óssea, Periodontal diseases, Bone resorption