RESUMO
This study aimed to characterize a preclinical model of critical size defect (CSD) in the radius of rabbits.Twenty adults (> 7 months), female, New Zealand Rabbits, weighing between 3,5 to 5 Kg were used. They underwent a 1.5 cm long ostectomy of the diaphysis of the radius, starting 2 cm from the carpus joint. Radiographic analyses were performed at 15, 30, 60, and 90 days postoperatively, in order to evaluated bone callus formation, periosteal reaction, and bone bridge formation.The methodology allowed to precisely create bone defects of 1.5cm. Over time, no bone deposition was found at 15 days, but mild bone callus formation was observed in three animals after 60 days postoperative. At 90 days postoperatively only one rabbit presented bone consolidation radiographically, the others presented non-union. The critical bone defect proposed in this study was satisfactory, feasible with very low risk of complications.
RESUMO
This study aimed to characterize a preclinical model of critical size defect (CSD) in the radius of rabbits.Twenty adults (> 7 months), female, New Zealand Rabbits, weighing between 3,5 to 5 Kg were used. They underwent a 1.5 cm long ostectomy of the diaphysis of the radius, starting 2 cm from the carpus joint. Radiographic analyses were performed at 15, 30, 60, and 90 days postoperatively, in order to evaluated bone callus formation, periosteal reaction, and bone bridge formation.The methodology allowed to precisely create bone defects of 1.5cm. Over time, no bone deposition was found at 15 days, but mild bone callus formation was observed in three animals after 60 days postoperative. At 90 days postoperatively only one rabbit presented bone consolidation radiographically, the others presented non-union. The critical bone defect proposed in this study was satisfactory, feasible with very low risk of complications.(AU)
O objetivo do presente estudo é caracterizar um modelo pré-clínico de falha óssea crítica em rádio de coelhos. Vinte coelhos adultos (> 7 meses), fêmeas, da raça New Zealand, pesando entre 3,5 e 5 kg foram utilizados. Os animais foram submetidos à ostectomia segmentar de 1,5 cm na diáfise do rádio, iniciando 2 cm acima da articulação carpo radial. As análises radiográficas foram feitas aos 15, 30, 60 e 90 dias pós-operatório, para avaliação de formação de calo ósseo, reação periosteal e formação de ponte óssea. nA metodologia permitiu a criação precisa de defeitos ósseo segmentar de 1,5 cm. Durante o experimento, não se observou deposição óssea na primeira avaliação radiográfica, porém após 60 dias foi possível visibilizar formação de calo ósseo em 3 animais. Aos 90 dias apenas um animal apresentou consolidação óssea radiograficamente; o restante apresentou não-união óssea. A falha óssea foi eficaz para estabelecer um defeito ósseo crítico além de apresentar fácil aplicação, apresentando pequeno índice de complicação.(AU)
Assuntos
Animais , Coelhos , Doenças Ósseas/veterinária , Rádio (Anatomia)/anormalidadesRESUMO
This study aimed to characterize a preclinical model of critical size defect (CSD) in the radius of rabbits.Twenty adults (> 7 months), female, New Zealand Rabbits, weighing between 3,5 to 5 Kg were used. They underwent a 1.5 cm long ostectomy of the diaphysis of the radius, starting 2 cm from the carpus joint. Radiographic analyses were performed at 15, 30, 60, and 90 days postoperatively, in order to evaluated bone callus formation, periosteal reaction, and bone bridge formation.The methodology allowed to precisely create bone defects of 1.5cm. Over time, no bone deposition was found at 15 days, but mild bone callus formation was observed in three animals after 60 days postoperative. At 90 days postoperatively only one rabbit presented bone consolidation radiographically, the others presented non-union. The critical bone defect proposed in this study was satisfactory, feasible with very low risk of complications.
O objetivo do presente estudo é caracterizar um modelo pré-clínico de falha óssea crítica em rádio de coelhos. Vinte coelhos adultos (> 7 meses), fêmeas, da raça New Zealand, pesando entre 3,5 e 5 kg foram utilizados. Os animais foram submetidos à ostectomia segmentar de 1,5 cm na diáfise do rádio, iniciando 2 cm acima da articulação carpo radial. As análises radiográficas foram feitas aos 15, 30, 60 e 90 dias pós-operatório, para avaliação de formação de calo ósseo, reação periosteal e formação de ponte óssea. nA metodologia permitiu a criação precisa de defeitos ósseo segmentar de 1,5 cm. Durante o experimento, não se observou deposição óssea na primeira avaliação radiográfica, porém após 60 dias foi possível visibilizar formação de calo ósseo em 3 animais. Aos 90 dias apenas um animal apresentou consolidação óssea radiograficamente; o restante apresentou não-união óssea. A falha óssea foi eficaz para estabelecer um defeito ósseo crítico além de apresentar fácil aplicação, apresentando pequeno índice de complicação.
Assuntos
Animais , Coelhos , Doenças Ósseas/veterinária , Rádio (Anatomia)/anormalidadesRESUMO
REASONS FOR PERFORMING STUDY: To investigate two protocols to provide antinociception in horses. OBJECTIVES: To evaluate the antinociceptive effects of intravenous methadone combined with detomidine or acepromazine in adult horses. STUDY DESIGN: Randomised, blinded, crossover study. METHODS: Mechanical, thermal and electrical stimuli were applied to the dorsal left and right metacarpus and coronary band of the left thoracic limb, respectively. A thermal stimulus was applied caudal to the withers. The horses were treated with saline (C), a combination of methadone (0.2 mg/kg bwt) and detomidine (10 µg/kg bwt) (MD) or methadone (0.2 mg/kg bwt) and acepromazine (0.05 mg/kg bwt) (MA) at 1 week intervals. Nociceptive thresholds were measured before and at 15 min intervals until 150 min after treatment. Wilcoxon rank-sum and Wilcoxon signed rank tests were used to compare data between groups at each time point and over time within each group, followed by the Bonferroni method to adjust the P value. RESULTS: The mechanical stimulus was the most sensitive test to differentiate the antinociceptive effects of the treatments. Mechanical thresholds were greater after MD than MA between 15 and 30 min and with both MD and MA these thresholds were greater than C from 15 to 60 min. Electrical and thermal limb thresholds were greater after MD than C at 15 and 45 min and at 15, 30, 45, 75 and 105 min, respectively. Thermal limb thresholds were greater with MA than C at 30 min. Thoracic thermal threshold in MD and MA were higher than C at 45, 75, 90 and 120 min and from 30 to 75 min, respectively. CONCLUSIONS: Methadone and acepromazine produced less pronounced mechanical antinociception than MD.