Navegando por Palavras-chave "Muculos oculomotores"

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    Efeito da bupivacaína na musculatura ocular extrínseca: achados histológicos em coelhos
    (Universidade Federal de São Paulo (UNIFESP), 2018-03-29) Hopker, Luisa Moreira [UNIFESP]; Allemann, Norma [UNIFESP]; http://lattes.cnpq.br/0956596522261307; http://lattes.cnpq.br/7383295373537539; Universidade Federal de São Paulo (UNIFESP)
    HOPKER, Luisa Moreira (2018). Bupivacaine effect in the extraocular muscles: histological findings in rabbits. Thesis (Doctorate). Post-Graduation Program in Ophthalmology and Visual Sciences. Federal University of Sao Paulo. Supervisor: Prof. Norma Allemann, MD. São Paulo: Universidade Federal de São Paulo – Escola Paulista de Medicina. INTRODUCTION: Bupivacaine (BUP) injection in extraocular muscles (EOM) has been used to correct small angle strabismus in adults. The mechanism of its action is not completely elucidated. PURPOSE: To evaluate changes in the cross-sectional area (CSA) of myofibers and their subtype distribution based on the myosin isoform expression after BUP injection in the EOM of rabbits in injected and not injected muscles. METHODS: A total of 32 rabbits received 0.3 ml of 1.5% BUP in the superior rectus (SR) of the right eye (OS) and were divided in groups and sacrificed at days 7, 28, 60, and 92 after injection. Eight animals did not receive any injection and were used as controls. Hematoxylin and eosin staining was performed, and ImageJ software was used to measure CSA of MOE. Immunohistochemical analysis was performed to analyze the proportion of myofibers positive for myosin types 1 (slow), 2 (fast) and embryonic. Collagen was analyzed through Sirius red stain. RESULTS: Myofiber area measurement decreased 7 days after BUP injection [SROD, 1271 ± 412 μm2 (control) to 909 ± 255 μm2 (day 7)], followed by a trend of increasing after 28 days and normalization after 92 days [SROD, 1492 ± 404 μm2 (day 60), 1317 ± 334 μm2 (day 92)]. The proportion of slow myosin-positive fibers increased in the 60-day group compared to control (0.885 ± 0.162 to 0.564 ± 0.163).). There was no statistically significant difference in fast myosin-positive fibers. The inferior rectus of both eyes, which was not treated, showed an increase in CSA after 7 days in the right inferior rectus [IR OS, 832 ± 250 μm2 (control) to 1097 ± 212 5 μm2 (day 7)], 60 days in the right and left inferior rectus [IR OD, 1085 ± 326 μm2 (control) to 1544 ± 475 μm2 (day 7) and IR OS 1707±972 μm2] and 92 days in the right and left inferior rectus [IR OD, 1776 ± 520 μm2 and IR OS 1647± 428 μm2]. CONCLUSIONS: After the injection of bupivacaine into the SR of rabbits, we observed an initial decrease of the fiber area related to necrosis, followed by a transient trend of increase in the area, and subsequent recovery to its initial size in the regeneration process. The transient increase in the proportion of slow myosin-positive fibers might play a role in force generation observed after BUP injection in clinical studies. We observed muscle adaptation in untreated EOM.