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| Author(s): |
Fernando José Dias
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2010-05-28 |
| Examining board members: |
Mamie Mizusaki Iyomasa;
Roelf Justino Cruz Rizzolo;
Selma Siessere
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| Advisor: | Mamie Mizusaki Iyomasa |
| Abstract | |
The laser therapy has been widely used as an alternative treatment in patients with chronic pain related to temporomandibular disorders. This is due to the effects: analgesic, anti inflammatory, muscle relaxant, reducing fatigue during tetanic contractions, increased bite strength and decrease in orofacial pain. Although clinical results are observed, is not well understood its effect on the cellular level. This study aims to analyze the effects of different densities (doses) irradiation of low level laser therapy (LLLI) on cellular level, on the masseter muscle of rats. The animals were randomly assigned to 6 groups (n=10), received 10 laser irradiation (GaAlAs, 780nm, 5mW spot and 0.04 cm²) on the left masseter muscle by varying the energy density (I. 0; II. 0.5; III. 1.0; IV. 2.5; V. 5.0 and VI. 20 J/cm²). After 10 irradiations the masseter muscles were obtained from animals under anesthesia for analysis: 1. Histoenzimologic for nicotinamide adenine dinucleotide (NADH), succinate dehydrogenase (SDH) and adenosine triphosphatase (ATPase), 2. Light microscopy (HE), 3. Transmission electron microscopy and 4. Immunohistochemistry for vascular endothelial growth factor (VEGF) and receptor 2 for VEGF (VEGFR-2). The activity of NADH in groups IV, V and VI (30±1,26; 33,47±2,15; 31,67±1,77 - intermediate fiber) increased significantly (p> 0.05) in oxidative metabolism in relation to other groups. The activity of SDH showed a slight increase, only the group V (32,2±1,61 intermediate fiber) increased significantly (p> 0.05), but the pattern of metabolic increase was very similar in both reactions. The ATPase activity showed no differences between groups nor in acid or alkaline. The qualitative analysis showed a pattern of increased expression of VEGF and VEGFR-2 directly proportional to the energy density of laser. Light microscopy showed rounded muscle fibers and peripheral flattened nuclei, which become more rounded with the highest energy densities. Ultrastructurally the irradiation with higher energy densities showed mitochondria of different sizes and shapes and dilated cisterns of sarcoplasmic reticulum between the myofibrils. It is concluded that higher densities of laser was able to increase the oxidative metabolism without altering the contractile capacity, increasing nuclei volume, modify ultrastructure of muscle fibers and the expressions of VEGF and VEGFR-2. (AU) | |