Morpho-functional evaluation of lateral pterygoid muscle and orofacial hypernociception at Parkinson experimental model

• Grant number: 16/21585-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2017
• End date: December 31, 2017
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Elaine Aparecida Del Bel Belluz Guimarães
• Grantee: Bruno Lima Malzone
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The musculoskeletal disorders, those caused by Parkinson Disease (PD), have highlighted by high prevalence in the elderly. It is known to that this disorder results from direct and indirect effects of PD and their main therapeutic drug (L-DOPA) in skeletal musculature, however, little is known about this disease consequences at masticatory muscles and orofacial nociception in parkinsonian patients. This study aims to investigate the effect of Parkinson's Disease, which is induced by injury of dopaminergic neurons in the medial forebrain bundle (MFB - nigrostriatal pathway), and whether or not administration of L-DOPA on the lateral pterygoid muscle and in acute and chronic orofacial nociception. Our hypothesis is that Parkinson's disease induces acute and chronic orofacial nociception changes and also changes in the morphology and physiology of the masticatory muscle to be studied. The influence of treatment with L-DOPA, a classic drug for Parkinson's Disease treatment, will also be evaluated. Will be used male Wistar rats (200g) randomly divided into two groups: Von Frey Group (VG): rats submitted to orofacial Von Frey test (n=32); and Formalin Group (FG): rats submitted to orofacial Formalin test (n=32). There will be the following subgroups (n=8): I and V: with Parkinson's Disease; II and VI: without Parkinson's Disease; III e VII: with Parkinson's Disease and chronic treatment with L-DOPA; IV e VIII: with Parkinson's Disease and chronic treatment with carrier. The rats will be submitted on the 46th day after experiment start to orofacial nociceptive tests and also to euthanasia for obtainment of the left and right lateral pterygoid muscle for histochemical analysis of hematoxylin and eosin (HE) and immunohistochemistry for Myosin Heavy Chain (MyHC). (AU)