Facial nerve identification with fluorescent dye in rats

PURPOSEThe parotidectomy technique still has an elevated paresis and paralysis index, lowering patient life's quality. The correct identification of the facial nerve can prevent nerve damage. Fluorescent dye identifies nerves in experimental studies but only few articles focused its use on facial nerve study in parotidectomies. We aimed to stain the rat facial nerve with fluorescent dye to facilitate visualization and dissection in order to prevent injuries.METHODSForty adult male Wistar rats were submitted to facial injection of saline solution (Gsf-control group, 10) or fluorescent dye solution (Gdye group, 30) followed by parotidectomy preserving the facial nerve, measuring the time for localization and facility of localization (LocTime and LFN). Nerve function was assessed using the Vibrissae Movements (PMV) and Eyelid Closure Motion (PFP) scores.RESULTSNerve localization was faster in Gdye group, with 83% Easy LFN rate. The Gdye group presented with low nerve injury degree and better PMV and PFP scores, with high sensitivity and accuracy.CONCLUSIONSThis experimental method of facial nerve fluorescence was effective for intraoperative nerve visualization, identification and preservation. The technique may be used in future facial nerve studies, translated to humans, contributing to the optimization of parotid surgery in the near future.(AU)

Platelet-rich plasma in bone repair of irradiated tibiae of Wistar rats / Plasma rico em plaquetas na reparação óssea em tíbias irradiadas de ratos Wistar

PURPOSE: To evaluate the influence of PRP addition on bone repair of circular defects created in irradiated tibiae of rats by histometric analysis. METHODS: Sixty male Wistar rats had the right tibiae irradiated with 30 Gy. After 30 days monocortical defects were created and platelet-rich plasma was applied in 30 rats. In the control group defects were created but not filled. The animals were desanguinated after 4, 7, 14, 21, 56 and 84 days and the tibiae removed for histological processing. RESULTS: There was a tendency in the PRP group to increased bone neoformation from 14-days to 84-days; in the control group increased bone neoformation was not seen after 21 days or later. CONCLUSION: The addition of platelet-rich plasma had a beneficial effect in the initial cellular regeneration period and enhanced bone formation in later periods when compared to control.(AU)

OBJETIVO: Avaliar histometricamente a influência do PRP na reparação óssea de defeitos circulares criados em tíbia irradiada de ratos Wistar. MÉTODOS: Sessenta ratos machos tiveram a tíbia direita irradiada com 30Gy. Após 30 dias, defeitos ósseos monocorticais foram criados e PRP foi adicionado em 30 ratos. No grupo controle os defeitos foram criados, mas não preenchidos. Os animais foram sacrificados em 4, 7, 14, 21, 56 e 84 dias e a tíbia removida para processamento histológico. RESULTADOS: Houve uma tendência do grupo PRP mostrar uma neoformação óssea significativamente maior nos períodos de 14 a 84 dias; no grupo controle o aumento da reparação óssea não se manteve após 21 dias. CONCLUSÃO: A adição de PRP mostrou-se benéfica no período inicial de reparação celular e em períodos seqüentes foi estímulo à quantidade neoformação óssea, quando comparado ao controle.(AU)

Aging histological changes in the cartilages of the cricoarytenoid joint

PURPOSE: Analysis of ossification, bone marrow formation, perichondrium thickness, muscle fibers, collagen fibers and elastic fibers quantities of cricoid and arytenoid cartilages. Design: Correlation morphologic study. METHODS: Twenty-four cricoarytenoid joints were obtained from Caucasian male fresh cadavers divided into three groups with eight specimens in each: group I - adolescents, from 15 to 20; group II - adults, from 25 to 35; and group III - elderly, from 60 to 75. The specimens were stained with H-E; trichrome; Picrosirius; and elastic stain. Histometry was performed for quantitative analysis. Bonferroni Test, Fisher Test and the Variance Analysis were used. RESULTS: At the microscopic analysis, the group I specimens presented typical hyaline cartilage, thin perichondrium, bulky muscle fibers and were surrounded by collagen fibers. In group II, there were ossification in small well defined central areas of four specimens, with lamellar bone tissue. In two of these cases there were central bone cavity full of fat tissue. The other parameters were similar to group I. In group III, most part of hyaline cartilage was replaced by typical lamellar bone tissue with poorly outlined haversian systems. Hematopoietic tissue was noted in six cases and fat tissue in the other two. Perichondrium was thicker. Small muscle fibers were smaller and surrounded by collagen in great quantity. Elastic fibers were present in small quantity in the outer portion of perichondrium in all the groups. CONCLUSIONS: In spite of its lack in adolescence, ossification occurs in cricoid and arytenoid cartilages during adulthood and intensifies with age; bone marrow is formed in ossification tissue with hematopoietic tissue in group III; perichondrium becomes thicker in group III; muscle tissue atrophies in group III and is replaced by collagen fibers; these fibers thicken with age; and elastic fibers is always present in the perichondrium in low quantity.

OBJETIVO: Análise da ossificação, formação de medula óssea, espessura do pericôndrio, da quantidade de fibras musculares, de colágeno e eláticas das cartilagens cricóidea e aritenóidea. Desenho: Estudo morfológico comparativo. MÉTODOS: Vinte e quatro articulações crico-aritenóideas foram obtidas de cadáveres frescos caucasianos masculinos, divididos em três grupos com oito espécimes cada: grupo I - adolescentes, de 15 a 20 anos; grupo II - adultos, de 25 a 35; e grupo III - idosos, de 60 a 75. Os espécimes foram corados com H.E.; tricrômio; Picrosirius; e coloração para fibras elásticas. Histometria foi realizada para a análise quantitativa. Teste de Bonferroni, Teste Exato de Fisher e a Análise de Variância foram utilizados. RESULTADOS: À análise microscópica, os espécimes do grupo I apresentaram cartilagem hialina típica, pericôndrio fino, fibras musculares espessas e cercadas por colágeno em pequena quantidade. No grupo II, havia ossificação em pequenas áreas centrais bem definidas em quatro espécimes, com tecido ósseo lamelar. Em dois desses casos, havia uma cavidade óssea central preenchida por tecido adiposo. Os demais parâmetros foram similares ao grupo I. No grupo III, a maior parte da cartilagem hialina estava substituída por típico tecido ósseo lamelar com sistemas de Havers. Tecido hematopoiético foi observado em seis casos e tecido adiposo nos outros dois. O pericôndrio estava espesso. As fibras musculares estavam menores e cercadas por colágeno em grande quantidade. Fibras elásticas estavam presentes em pequena quantidade na porção externa do pericôndrio em todos os grupos. CONCLUSÕES: Apesar de sua ausência na adolescência, a ossificação occorreu nas cartilagens cricóidea e aritenóidea durante a idade adulta e intensificou-se com a idade; medula óssea é formada no tecido de ossificação com tecido hematopoiético no grupo III; o pericôndrio tornou-se espesso no grupo III; as fibras musculares atrofiaram no grupo III e foram substituídas por fibras de colágeno; estas fibras espessaram-se com a idade; e as fibras elásticas estavam sempre presentes no pericôndrio em pequena quantidade.