The aim of this research was to evaluate the process of bone regeneration in rabbits, using chitosan and beta-tricalcium phosphate (β-TCP) independently and in combination. A total of 12 New Zealand rabbits of both sexes, with average weight of 3.0 ± 0.57 kg were used. Animals were randomly divided into two experimental time points, with six animals euthanized 45 days after surgery and six euthanized 90 days after surgery. We performed two osteotomies in each tibia. The left tibia was used for the chitosan (QUI) and control groups, and the right tibia was used for the β-TCP alone and in combination with chitosan (QUI+TCP) groups. Tomographic evaluation showed no statistically significant difference among groups; however radiopacity was higher in the treated groups. Comparative descriptive histological evaluation found that treatment groups stimulated a more pronounced tissue repair reaction and accelerated bone repair. Morphometric analysis showed that treatment groups presented statistically higher bone formation compared with the control group.

RESUMOTestou-se a hipótese de o alo-transplante de bexiga devolver a capacidade estrutural e funcional desse órgão, usando-se 10 cães machos, saudáveis, submetidos à cistectomia parcial com preservação do trígono vesical. Utilizou-se o alo-transplante na reconstrução da vesícula urinária com acompanhamento dos animais durante 60 dias. Aos oito dias de pós-operatório, os cães apresentavam capacidade de contenção urinária e micção espontânea. Houve aumento gradativo do volume da vesícula urinária, alcançando, aos 60 dias, valores significativamente mais altos que os observados antes da cirurgia. Verificou-se integração tecidual com regeneração parcial na interface do transplante, caracterizada por reconstituição epitelial, proliferação fibroblástica, neoangiogênese e surgimento de fibras musculares lisas, aos 60 dias. Problemas como rejeição e obstrução uretral ocorreram em três cães. Conclui-se que o alo-transplante de bexiga em cães é viável e devolve a capacidade de repleção e as demais funções fisiológicas da vesícula urinária, ocorrendo regeneração parcial dos tecidos aos 60 dias de pós-operatório. Palavras-chave: cão, alo-transplante, bexiga ABSTRACT The hypothesis that urinary bladder allotransplant in dogs repairs

RESUMO

Objectives: The aim of the present study was to evaluate bone repair in defects induced in the cranium of Wistar rats using β-tricalcium phosphate. Study Design: In this research, we used 30 rats, randomly distributed in three groups of 10 animals (G1, G2 and G3), corresponding respectively to time of histological evaluation (7, 15 and 30 days). This was a paired study, a defect being induced in the parietal bone on either side of the median sagittal suture of the animals, being the left-hand side the experimental subgroup (filled by biomaterial) and the right control. The histological evaluation was performed by means of light microscopy. The collected data were submitted to the Fisher Exact test for comparison between the groups and to the McNemar test for comparison between the subgroups (P > 5%). Results: The results showed no statistically significant differences between the groups and bone regeneration was similar at the different times of evaluation. Conclusions: Therefore, we concluded that β-tricalcium phosphate has not contributed significantly to repair process of defects induced in the cranium of Wistar rats.

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