Effects of the systemic use of steroids in post-traumatic facial nerve regeneration: experimental study in rabbits

• Grant number: 08/01374-3
• Support Opportunities: Regular Research Grants
• Start date: July 01, 2008
• End date: June 30, 2009
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Paulo Roberto Lazarini
• Grantee: Paulo Roberto Lazarini
• Host Institution: Faculdade de Ciências Médicas da Santa Casa de São Paulo (FCMSCSP). Fundação Arnaldo Vieira de Carvalho. São Paulo , SP, Brazil

Abstract

Posttraumatic peripheral facial palsy assumes big importance nowadays as the incidence of car accidents and physical aggressions has been drastically rising. The facial nerve is the cranial nerve most commonly affected by head and neck traumatic injuries due to its extensive intratemporal route into the facial canal, which is the most affected part. Recently, therapeutic resources for complete section of the facial nerve have improved due to the development of neural repair techniques. However, in incomplete sections of the nerve, the treatment is based on clinical therapy and, therefore, depends on the development of new drugs or methods that are able to help the process of neural regeneration. The discovery of substances that act on the posttraumatic regeneration of the facial nerve may contribute to the treatment of patients with this illness. Understanding the regeneration of the facial nerve after traumatic injury is essential for the search of the quickest function recovery of this important cranial nerve. Systemic corticotherapy has been used as one of the therapeutic approaches on the treatment of patients that suffer from this health problem, which can also result from other sources, such as Bell's peripheral palsy. Even though this medication is widely used for this pathology, there are still doubts concerning its real benefits in the process of neural regeneration. In this study, 20 rabbits will be submitted to bilaterally crushing injury of extratemporal facial nerve, and will be divided into control group and treated group (1 ml of betamethasone dipropionate intramuscle right after lesion). The animals will be analyzed by electromyography activity exam of the facial muscle tissue (action potential timing) during observation period and will be re-operated to remove the facial nerve after 14 or 28 days after the first lesion. The obtained facial nerve will be submitted to histological evaluation, in order to observe the qualitative and quantitative aspects of the myelinated axons. The comparison of results between control and treated groups may bring information concerning the effectiveness of the systemic corticotherapy in this kind of palsy. (AU)