O estresse crônico e a via de sinalização adrenérgica no desenvolvimento da lesão periapical
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Data
2017-12-01
Autores
Khoury, Rayana Duarte
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os objetivos deste estudo são: 1) Esclarecer a possível associação entre o estresse crônico e a estimulação do Sistema Nervoso Simpático (SNS) e investigar sua interferência no desenvolvimento e progressão da lesão periapical; 2) Avaliar a quantidade de receptores para os neurotransmissores na região periapical; 3) Elucidar uma via farmacológica de modulação inflamatória através do uso de bloqueadores adrenérgicos. Trinta e dois ratos Wistar foram submetidos à modelo animal de lesão periapical através da exposição da cavidade pulpar e em seguida foram aleatoriamente divididos em 4 grupos: sem estresse (NS); estresse + solução salina (SS); estresse + β-bloqueador (Sβ); estresse + α-bloqueador (Sα). Os grupos SS, Sβ e Sα foram submetidos à modelo animal de estresse crônico durante 28 dias e receberam injeções diárias de solução salina, propranolol (β bloqueador adrenérgico) e fentolamina (α bloqueador adrenérgico), respectivamente. Após 28 dias os animais foram eutanasiados e procedeu-se as seguintes análises: a) dos níveis séricos de corticosterona através de Radioimunoensaio; b) histomorfométrica por coloração com hematoxilina e eosina; c) da estrutura óssea periapical através de microtomografia computadorizada (micro-CT); d) expressão de receptores β e α adrenérgicos; e) da atividade osteoclástica através de histoquímica para fosfatase ácida resistente ao tartarato (TRAP). Os resultados obtidos mostram um aumento do nível sérico de corticosterona dos animais do grupo SS sendo estatisticamente significante comparados aos animais do grupo NS (sem estresse) (p<.05). Nenhuma diferença estatística foi observada a nível histológico uma vez que todos os animais apresentaram infiltrado inflamatório moderado e área de lesão periapical similares. A análise por micro-CT também mostrou similaridade da área e volume da lesão periapical em todos grupos. Através da histoquímica para TRAP verificou-se uma quantidade significativamente menor de osteoclastos nos grupos que receberam bloqueadores adrenérgicos (Sβ e Sα) (p<.05). Conclui-se que não houve influência significativa do estresse crônico no desenvolvimento e progressão da lesão periapical e a administração de bloqueadores adrenérgicos apesar de não ter sido capaz de modular a resposta inflamatória, diminuiu significativamente o número de osteoclastos na região periapical.
The objectives of this study are: 1) To clarify the possible association between chronic stress (CS) and stimulation of the Sympathetic Nervous System (SNS) and to investigate its interference in the development and progression of periapical lesion; 2) To evaluate the amount of receptors for neurotransmitters in the periapical region; 3) To elucidate a pharmacological pathway of inflammatory modulation through the use of adrenergic blockers. Thirty- two Wistar rats were submitted to animal model of periapical lesion through exposure of the pulp cavity and were then randomly divided into 4 groups: no stress (NS); stress + saline solution (SS); stress + β-blocker (Sβ); stress + α-blocker (Sα). The SS, Sβ and Sα groups were submitted to animal model of CS for 28 days and received daily injections of saline solution, propranolol (β blocker adrenergic) and phentolamine (α adrenergic blocker), respectively. After 28 days the animals were euthanized and the following analysis were carried out: a) serum corticosterone levels through Radioimmunoassay; b) histomorphometric by staining with hematoxylin and eosin; c) periapical bone structure through micro computed tomography; d) expression of β and α adrenergic receptors; e) osteoclast activity by histochemistry for tartrate resistant acid phosphatase (TRAP). The results obtained show an increase in the seric corticosterone level of the animals of the SS group being statistically significant compared to the NS group animals (without stress). No statistical difference was observed histologically since all animals had moderate inflammatory infiltrate and similar periapical lesion area. Micro-CT analysis also showed similarity of the area and volume of the periapical lesion in all groups. Through histochemistry for TRAP, a significantly lower amount of osteoclasts was observed in the groups receiving adrenergic blockers (Sβ and Sα). It was concluded that there was no significant influence of chronic stress on the development and progression of the periapical lesion and the administration of adrenergic blockers despite not being able to modulate the inflammatory response, significantly decreased the number of osteoclasts in the periapical region.
The objectives of this study are: 1) To clarify the possible association between chronic stress (CS) and stimulation of the Sympathetic Nervous System (SNS) and to investigate its interference in the development and progression of periapical lesion; 2) To evaluate the amount of receptors for neurotransmitters in the periapical region; 3) To elucidate a pharmacological pathway of inflammatory modulation through the use of adrenergic blockers. Thirty- two Wistar rats were submitted to animal model of periapical lesion through exposure of the pulp cavity and were then randomly divided into 4 groups: no stress (NS); stress + saline solution (SS); stress + β-blocker (Sβ); stress + α-blocker (Sα). The SS, Sβ and Sα groups were submitted to animal model of CS for 28 days and received daily injections of saline solution, propranolol (β blocker adrenergic) and phentolamine (α adrenergic blocker), respectively. After 28 days the animals were euthanized and the following analysis were carried out: a) serum corticosterone levels through Radioimmunoassay; b) histomorphometric by staining with hematoxylin and eosin; c) periapical bone structure through micro computed tomography; d) expression of β and α adrenergic receptors; e) osteoclast activity by histochemistry for tartrate resistant acid phosphatase (TRAP). The results obtained show an increase in the seric corticosterone level of the animals of the SS group being statistically significant compared to the NS group animals (without stress). No statistical difference was observed histologically since all animals had moderate inflammatory infiltrate and similar periapical lesion area. Micro-CT analysis also showed similarity of the area and volume of the periapical lesion in all groups. Through histochemistry for TRAP, a significantly lower amount of osteoclasts was observed in the groups receiving adrenergic blockers (Sβ and Sα). It was concluded that there was no significant influence of chronic stress on the development and progression of the periapical lesion and the administration of adrenergic blockers despite not being able to modulate the inflammatory response, significantly decreased the number of osteoclasts in the periapical region.
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Palavras-chave
Estresse crônico, Lesão periapical, Bloqueadores adrenérgicos, Propranolol, Fentolamina, Chronic stress, Periapical lesion, Adrenergic blockers, Propranolol, Phentolamine