Because bone morphogenetic protein 2 gene transfected Escherichia coli (E-BMP-2) produce recombinant human BMP-2 (rhBMP-2) more efficiently than mammalian cells (Chinese hamster ovary [CHO]-BMP-2), they may be a more cost-effective source of rhBMP-2 for clinical use. However, use of E-BMP-2 for regenerating long bones in large animals has not been reported. In the current study, we evaluated the healing efficacy of E-BMP-2 in a canine model. We created 2.5-cm critical-size segmental ulnar defects in test animals, then implanted E-BMP-2 and 700 mg of artificial bone (beta-tricalcium phosphate; β-TCP) into the wounds. We examined the differential effects of 5 E-BMP-2 treatments (0, 35, 140, 560, and 2240 μg) across 5 experimental groups (control, BMP35, BMP140, BMP560, and BMP2240). Radiography and computed tomography were used to observe the regeneration process. The groups in which higher doses of E-BMP-2 were administered (BMP560 and BMP2240) displayed more pronounced bone regeneration; the regenerated tissues connected to the host bone, and the cross-sectional areas of the regenerated bone were larger than those of the originals. The groups in which lower doses of E-BMP-2 were administered (BMP35 and BMP140) experienced relatively less bone regeneration; furthermore, the regenerated tissues failed to connect to the host bone. In these groups, the cross-sectional areas of the regenerated bone were equal to or smaller than those of the originals. No regeneration was observed in the control group. These findings suggest that, like CHO-BMP-2, E-BMP-2 can be used for the regeneration of large defects in long bones and that its clinical use might decrease the cost of bone regeneration treatments.

Objectives: Severe intervertebral disc herniation causes complete paraplegia and loss of pain sensation in canines. The prognosis is poor, even when decompression surgery is performed immediately after onset. Studies suggest that bone marrow-derived mononuclear cells will regenerate the injured spinal cord and restore neurologic function. This study was conducted to assess the clinical efficacy of bone marrow-derived mononuclear cell autotransplanting in severe cases of canine intervertebral disc herniation. Materials and Methods: Eighty-two dogs (miniature dachshunds) with severe thoracolumbar intervertebral disc herniation were used. All had intervertebral disc herniation accompanied by paraplegia and loss of pain perception. In 36 dogs, bone marrow-derived mononuclear cells were autotransplanted to the lesioned spinal cord immediately after decompression surgery. Bone marrow was collected from the proximal humerus and subjected to density gradient centrifugation to isolate the bone marrow-derived mononuclear cells. The remaining 46 dogs (receiving surgical treatment only) were assigned as controls.Therapeutic efficacy was compared based on the rate of ambulatory recovery. Results: Ambulatory recovery was observed in 88.9% and 56.5% of animals in the bone marrowderived mononuclear cells and control groups, and a significant difference was found. No complications were found in bone marrow-derived mononuclear cells group. Conclusions: Bone marrow-derived mononuclear cell transplanting revealed a significant increase in the recovery rate and, as has been reported in rats and humans, bone marrow-derived mononuclear cell autotransplanting shows efficacy in canines as well.

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Objectives This study aimed to investigate the effects of intramuscular medetomidine and xylazine on tear flow in healthy cats. Methods Five cats each received medetomidine 10, 20, 40 and 80 µg/kg IM; xylazine 1.0, 2.0, 4.0 and 8.0 mg/kg IM; and physiological saline (2.0 ml IM) in a randomised order separated by intervals of at least 1 week. The Schirmer tear test (STT) I was performed in both eyes before and 0.25, 0.5, 0.75, 1, 2, 3, 4, 5, 6, 7, 8 and 24 h after each dose. Results The STT I value decreased significantly at 0.5 and 1.0 h and at 0.75 and 1.0 h in both eyes after administration of medetomidine at 10 or 40 µg/kg. After administration of medetomidine 80 µg/kg, there was a significant decrease in the STT I reading at 0.75, 2 and 3 h in the left eye and 0.75, 1, 2 and 3 h in the right eye. The STT I value decreased significantly at: 0.5, 0.75, 1 and 2 h in the left eye and 0.75 h in the right eye after administration of xylazine 1.0 mg/kg; 0.5, 0.75, 1 and 2 h in the left eye and 0.5, 0.75, 1 and 3 h in the right eye after administration of xylazine 2.0 mg/kg; 0.5, 0.75, 1 and 2 h in both eyes after administration of xylazine 4.0 mg/kg; and 0.5, 0.75, 1, 2 and 3 h in the left eye and 0.75, 1, 2, 3 and 4 h in the right eye after administration of xylazine 8.0 mg/kg. Conclusions and relevance Both medetomidine and xylazine significantly decreased feline tear flow measured by STT I. Therefore, the ocular surface should be monitored carefully and protected appropriately in cats treated with these sedatives.

BackgroundLarge bone defects in canines usually require assistance to achieve healing. Implantation of osteoinductive factors can promote bone healing, while transplantation of osteoprogenitor cells can enhance bone regeneration. We hypothesized that implantation of an osteoinductive factor, recombinant human bone morphogenetic protein-2 (rhBMP-2), combined with osteoprogenitor cells, bone marrow-derived mesenchymal stromal cells (BMSCs), would synergistically promote bone healing. In this study, we examined the combined effects of Escherichia coli-derived rhBMP-2 and BMSCs on bone healing after implantation into canine ulnar defects.ResultsCritical-sized osteoperiosteal segmental defects (2.5 cm) were created in the ulnae of healthy female beagle dogs, and implanted with combinations of E. coli-derived rhBMP-2 (560 or 140 μg) and autologous BMSCs (107, 105, or 0 cells). In the present study,18 forelimbs of nine healthy purpose-bred female beagles were used. All six treatment groups contained three forelimbs, and the animals were euthanized after 12 weeks. The control groups (560 and 140 μg/0 cells) were cited from our previous study to reduce the number of experimental animals. Radiographically, the regenerated bone width was significantly increased in the 560 or 140 μg with 107 and 105 cells groups compared with the 0 cells groups. By quantitative CT, the bone mineral density was higher in the 560 μg with 107 and 105 cells groups, while non-uniformity of the bone mineral density was improved in the 560 μg with 107 and 105 cells groups and 140 μg/107 cells group. Mechanically, the maximum loads at failure were significantly higher in the 560 μg with 107 and 105 cells groups. Histologically, the regenerated bone was well-developed and contained osteocyte-like cells marrow cavities, and vessels. However, the osteoclasts and osteoblasts were hardly observed. The osteocyte-like cell numbers were significantly higher in the 560 μg with 107 and 105 cells and 140 μg with 107 and 105 cells groups.ConclusionsImplantation of E. coli-derived rhBMP-2 and BMSCs led to significantly enhanced bone formation, with improved bone mineral density and reduced non-uniformity of the regenerated bone. Combined implantation of rhBMP-2 and BMSCs may be useful for promotion of bone healing in critical-sized defects in canines.