Nandrolone decanoate in induced fracture nonunion with vascular deficit in rat model: morphological aspects.

BACKGROUND: The nonunion fracture is a relatively frequent complication in both human and veterinary medicine. Specifically, atrophic fracture nonunions are difficult to treat, with revision surgery usually providing the best prognosis. Anabolic steroids, such as nandrolone decanoate (ND), have been reported to have beneficial clinical effects on bone mass gain during osteoporosis; however, their utility in promoting regeneration in atrophic nonunions has not been documented. Our objective was to examine morphological changes induced by the ND in experimental fracture nonunion with vascular deficit in the rat model. METHODS: Fourteen adult Wistar rats had an atrophic fracture nonunion induced in the diaphysis of their left femur. Rats were allocated into two groups: control group and nandrolone decanoate group. Rats in the latter group were given nandrolone decanoate (1.5 mg/kg IM, once a week, during 4 weeks after confirmation of fracture nonunion radiographically). Radiographic and anatomopathological examination, micro-tomography and histological analysis were assessed to characterize the morphological changes promoted by the nandrolone decanoate use. RESULTS: Based on radiology, anatomopathological evaluation, computed micro-tomography and conventional microscopy, nandrolone decanoate promoted bone regeneration at the fracture nonunion site by increasing the cellularity at the fracture site. Percentage of collagen was not significantly different between groups, consistent with high-quality regenerated bone. CONCLUSION: The anabolic steroid nandrolone decanoate improved bone mass and regeneration without affecting collagen production and therefore has potential for improving outcomes for atrophic fracture nonunion.

Lumbosacral plexus in Brazilian Common Opossum.

The opossum has been suggested as an animal model for biomedical studies due to its adaptability to captivity and number of births per year. Despite many studies on morphology and experimental neurology using this opossum model, the literature does not offer details of the nerves of the lumbosacral plexus in this species. Ten lumbosacral plexus were dissected to describe the peripheral innervations of the Brazilian Common Opossum (Didelphis aurita) and compare the results with Eutheria clade species. The tensor fasciae latae muscle was absent and there was only one sartorius muscle for each limb. The distribution of the nerves were similar to other mammals, except for the caudal gluteal nerve, sartorius muscle innervations and the position of the pudendal nerve which arose from the major ischiatic foramen together with the ischiatic nerve, the cranial gluteal nerve and the caudal gluteal nerve. No anatomical variation was found. The special position of the pudendal nerve suggested that the Brazilian Common Opossum is a better model than rats or rabbits in surgical procedures with that specific nerve. In addition, the study revealed that the pelvic limb nerves are not an invariable structure of reference for muscle homology and homonym as reported previously. New investigation using other species of opossums are necessary to best comprehend the lumbosacral plexus distribution in the Methatheria clade and to confirm that other opossum species is eligible as a good model for pudendal nerve studies.

Acceptance of the bodypainting as supportive method to learn the surface locomotor apparatus anatomy of the horse.

Although bodypainting has been reported as a great resource for teaching surface anatomy of humans, its use in veterinary anatomy has not been scientifically reported. In the present study, bodypainting was performed on 4 horses for anatomy teaching purposes of the equine locomotor apparatus. We aimed to use the bodypainting method as an additional tool to classic teaching and to test the relevance of our purpose. Twenty one Brazilian veterinary students were given a 90-min session, which included a presentation of painted horses, with opportunities for the students to ask questions and to palpate anatomic locations on the horses. Based on a questionnaire, there was unanimous student satisfaction with this technique. Furthermore, student scores on practical tests to evaluate the attention retain given immediately before and 1 h after the session were 33.9 ± 19.8% and 69.0 ± 18.4%, respectively (p < 0.001). We concluded that bodypainting has great potential for support the classic lectures of the equine locomotor apparatus.

Novel rat model of nonunion fracture with vascular deficit.

Nonunion fractures occur frequently in humans, with profound implications (medical and non-medical). Although there are numerous animal models to study pathogenesis and treatment of nonunion fractures, there is apparently the lack of a definitive model for atrophic nonunion fracture. Therefore, the objective was to develop a low-cost rat model of nonunion fracture with a vascular deficit that enabled standardized quantitative analysis of bone growth and regeneration. The model was developed with two surgeries, performed apart. The first involved osteotomy of the femur diaphysis, removal of periosteum and endosteum, isolation of the fracture site using a latex artefact (Penrose drain tube), and reduction of the fracture using an intramedullary pin, whereas the second surgery was to remove the latex artefact. Based on radiographic imaging, micro-CT and histological analyses done 125 days after the fracture was induced, there was clear evidence of atrophic nonunion fracture, without pin migration or specimen loss. Perceived advantages of this model included low cost, ease of reproducibility, lack of specimen loss, and, finally, the potential to assess bone growth and regeneration under poor vascular conditions.

Gross morphometry of the heart of the Common marmoset.

The Callithrix jacchus is a Brazilian endemic species that has been widely used as an experimental model in biomedical research. Anatomical data are necessary to support experimental studies with this species. Eleven hearts of C. jacchus from the German Primate Centre (DPZ) have been studied in order to characterize their gross morphometry and compare them with other animal models and human. Biometric data were also obtained. The mean values for morphometry of the hearts did not show any significant difference between male and female. The relative heart weight was similar to human, bovine and equine species. Considering those aspects, the C. jacchus could be used as non-human primate experimental model for biomedical studies on heart.