The effect of carbon dioxide therapy on composite graft survival

PURPOSE: To investigate the effect of carboxytherapy in auricular composite grafts in rabbits. METHODS: An experimental study was conducted using 20 rabbits randomly assigned to a treatment group of carboxytherapy or a control group of saline solution. In each ear, a circular graft with 1.5 cm or 2 cm of diameter was amputated and reattached. Animals underwent carbon dioxide or saline injection four times during the experiment. We analyzed clinical evolution of the animals, grafts survival, histopathology features and histomorphometry of collagen. RESULTS:The treated group had a significantly lower weight gain (p=0.038). Histopathology was not significantly different between groups. There was an increase in amount of collagen in 2 cm grafts submitted to carbon dioxide therapy (p=0.003). Carboxytherapy didn't influence graft survival rate for 1.5 cm grafts or 2 cm grafts (p=0.567 and p=0.777, respectively). CONCLUSIONS:Carbon dioxide therapy increased the amount of collagen in 2 cm grafts. CO2 was not significantly different from saline infusion on composite grafts survival, but this study suggests that there is a mechanical effect caused by distension which favored graft survival.

[Role of pinna cartilage autograft on long bone healing in dog: radiographic and biomechanical studies]

To evaluate the feasibility of pinna cartilage autograft in healing of long bone defects in dogs. Experimental study. Mid-diaphyseal region of the right radial bone of ten Mongrel dogs of both sexes with average weight of 29 +/- 2.4 kg, which were randomly assigned to either control [n=5] or experimental group [n=5]. Creation of a bone gap at the mid-diaphyseal region of the right radius in each dog followed by cosmetic ear trimming. Insetion of a piece of pinna cartilage within the bone defect in experimental group was done and postoperative lameness scored. Radiographic evaluation in two views every 2 weeks for 70 days was performed. The dogs were euthanized after 70 days and their operated and intact radial bones were subjected to bending test. Repeated measures ANOVA and independent t-test were done for callus index measurements. Results of lameness scores were evaluated using Kruskal-Wallis test. Lameness scores were statistically improved in experimental group by the time, as compared with control group. Callus index was statistically greater in experimental group at 28, 42,56 and 70 days after surgery than the previous days. [P<0.05]. Biomechanical quality [maximum load, elastic modulus, and maximum bending moment] enhanced in the operated bones of experimental group. The results of this study revealed that pinna cartilage in dogs may be used as an available chondrocyte-rich autograft to enhance bone healing process in fractures at risk to enhance bone healing process in fractures at risk of delayed or non-union treatment of both conditions, and in bone defects

Histological study of blastema tissue genesis processes, autografted in Newzealand rabbit derm

Blastema tissue is a group of undifferentiated cells that exists circulary in the pinna holes punched region, that has a rapid distinction and division process.These cells could be attended in genesis and development of holes punched regions so that after two months the region will be repaired perfectly. This characteristic is not seen in other mammals. The aim of this investigation is to study blastema tissue genesis process, autografted in rabbits. In this experimental study 6 white Newzealand rabbits, about 2.5kg and 2-2.5 months age were choosen. Their ears were anaesthetized with lidocaine spray and punched-hole manually with a special puncher. Three circular holes, 4 mm in diameter, were punched in right ear [test group]. After three days with another puncher [8mm in diameter] a circular blastema from the edge of holes was separated and replaced in the split that was created in the dermis at the back of the same animal. Immediately after punching left ear the punched tissue was inserted into the derm of the left side of back in the same animal [as control group]. Then at the 9[th], 10[th] and 13[th] days of experiment under deep anesthesia histologic speciments were cut and histological investigation were made by PAS, H and E and toluidine blue methods. Data was analyzed using one way ANOVA and tukey tests. Microscopic studies in case group in comparison to control group showed a significant increase of skin epithelial tissue, vascularity and angiogenesis [p<0.05] and also more sebaceous glands and hair follicles [p<0.05]. As mentioned above, blastema of rabbit ears shows certain characteristics including pluripotency. Therefore this tissue could be affected by environmental signals and consequently transformed into different tissues