Resumo em Inglês:

Abstract Purpose: To evaluate bone formation through ultrastructural analysis around titanium implants in severe alloxanic uncontrolled diabetic rats, and controlled with insulin, in comparison with nondiabetic rats. Methods: Thirty-six male Wistar rats, weighing between 200 and 300 g, divided into three experimental groups: normal control group (G1), a diabetic group without treatment (G2), and a diabetic group treated with insulin (G3). The animals received titanium implants in the right femur, and osseointegration was evaluated at 7, 14, and 21 days after surgery, through ultrastructural analysis using scanning electron microscopy. Results: The ultrastructural analysis showed a dense bone structure in the G1, few empty spaces and a small number of proteoglycans; G2 presented bone matrix with a loose aspect, irregular arrangement, thin trabeculae, empty spaces and a large number of proteoglycans; G3 obtained similar results to G1, however with a higher number of proteoglycans. Conclusion: Severe diabetes caused ultrastructural changes in bone formation, and insulin therapy allowed an improvement in osseointegration, but it was not possible to reach the results obtained in the control group.

Resumo em Inglês:

Abstract Purpose: In this experimental study, activated protein C (APC), which has anticoagulant, antithrombotic, profibrinolytic, anti-inflammatory and antiapoptotic properties, was used to prevent coagulopathy in a disseminated intravascular coagulation (DIC) model formatted with lipopolysaccharide (LPS) infusion. Methods: Twenty-five Wistar albino rats weighting 280 – 320 g each were used. They were randomly divided into three groups: sham, control and study groups. To sham group (n = 5), only normal saline was infused. To control (n = 10) and study groups (n = 10), 30 mg/kg LPS was infused for 4 h from femoral vein. After LPS infusion, 100 µg/kg recombinant APC was given during 4 h in study group. Eight hours later, blood samples were taken from abdominal aorta and the animals sacrificed. From these samples, platelet, prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen and D-dimer levels were studied. Results: Platelet counts and fibrinogen levels were significantly lower in control and study groups than sham group (p < 0.05). The PT, aPTT and D-dimer levels were significantly higher in control and study groups than in sham group (p < 0.05). When comparing control and study groups, platelet counts were not statistically different (p = 0.36). However, the difference of the fibrinogen levels was significant between these groups (p = 0.0001). While PT and aPTT were longer in the study group compared to the control group (p < 0.05), D-dimer levels were lower in the study group than in control (p = 0.0001). Conclusion: Use of APC can prevent hypercoagulation and consumption coagulopathy in the DIC as a result of correcting hematological parameters other than prolongation of coagulation time.

Resumo em Inglês:

Abstract Purpose: To evaluate the effects of low-frequency electric stimulation on biomechanics following surgical treatment of the Achilles tendon in rats. Methods: Forty-two rats were divided into two groups. One was given electric stimulation and the other was not. All were submitted to Achilles tenotomy and tenorrhaphy performed with a modified Kessler stitch. The experiment group underwent electric stimulation with 2 Hz, a nonpolarized current of 1 mA intensity for 14 days. The animals were euthanized at 2, 4 and 6 weeks for the biomechanical study. Results: The work performed, that is, the tendon’s capacity to absorb energy until rupture, was greater in the electrically stimulated group in the 2nd (p = 0.032) and in the 6th week (p = 0.010). The maximum tension, which is the capacity to support a load, was higher in the treated group in the 2nd (p = 0.030) and the 6th week (p = 024). These results indicate greater resistance of the electrically stimulated tendons. An analysis of the elastic module showed no differences. Conclusion: Low-frequency electric stimulation increased the resistance of the tendons at 2 and 6 weeks of evolution in rats.

Resumo em Inglês:

Abstract Purpose: To develop a simpler animal model for benign tracheal stenosis and introduce a low-cost household endoscope for postmodeling endotracheal evaluation. Methods: Twenty rabbits were randomly divided into a model group (15 rabbits, subjected to transoral nylon brush scraping of the trachea) and a mock group (5 rabbits, merely exempted from scraping), a household endoscope was then introduced for weekly endoscopic examination. Meanwhile, other 15 rabbits (modeling like the model group) underwent batch tracheal resection at different postintervention times for pathological analysis. Results: The model group presented a low mortality and few complications. The endoscope could obtain adequate images for stenosis assessment, which showed that the models presented homogeneous injury after scraping and developed a mature scar stricture at 28 days postoperatively with a mean stenosis degree of 65.9%, and 71.4% (10/14) above Myer–Cotton’s grade II. The pathological findings were consistent with the clinicopathological process of human. No stenosis was found in mock group. Conclusion: The modified model is simpler, minimally invasive and reliable, while the household endoscope is competent for model’s follow-up, providing easily accessible and useful tools for facilitating more extensive studies of benign tracheal stenosis.

Resumo em Inglês:

Abstract Purpose To assess the action of pentoxifylline, administered by subcutaneous route, on skin flap tissue repair in rats, and to verify the histological aspects and biomarkers. Methods Thirty-two male Wistar rats were divided into four groups: control (CT) and treated with pentoxifylline (P1, P3 and P5). Modified McFarlane technique flap was used. Ten days later, the animals were euthanized and the areas of viable and necrotic tissue were evaluated. Hematoxylin/eosin staining was used to assess the morphometric characteristics of the number of vessels and epithelial thickness. Picrosirius red was used to assess collagen density. VEGF and TGF-?1 levels on the skin flap and serum of the animals were measured by the ELISA method. Results The macroscopic evaluation of the skin flap dimensions showed reduced necrotic tissue in the pentoxifylline (p < 0.05) treated groups. There was an increase in angiogenesis and reepithelization, demonstrated by analyses with an increased number of vessels (p < 0.05), VEGF and epithelial thickness. Fibrogenic effect showed decreased collagen density and TGF-β1 in the skin flap and serum. Conclusion The benefits of pentoxifylline administered by subcutaneous route, at dose 100 mg/kg, which was effective to improve the survival of skin flap by acting on tissue repair components, stimulating angiogenesis and reepithelization, in addition to reducing fibrogenesis

Resumo em Inglês:

Abstract Purpose To evaluate renal histological changes by stereology and morphometry and analyze the main markers of oxidative stress in rats undergoing natural aging. Methods Seventy two Wistar rats were divided into six groups of 12 rats each, which were euthanized at 3, 6, 9, 12, 18, and 24 months of age. Right kidney was stereologically and morphometrically analyzed to calculate the volumetric density (Vv[glom]), numerical density (Nv[glom]) and glomerular volume (Vol[glom]). Left kidney was used to determine the levels of nonprotein thiols, lipid peroxidation, and protein carbonylation, as well as the activities of superoxide-dismutase and catalase enzymes. Results Both Vv[glom] and Nv[glom] values showed gradual decreases between groups. Activity of superoxide-dismutase was elevated at 24 months of age, and the levels of nonprotein thiols were higher in older animals. Greater catalase activity and protein carbonylation were observed in animals between 6 and 12 months of age but lessened in older rats. Lipid peroxidation decreased in the older groups. Conclusions Morphometric and stereological analyses revealed a gradual decrease in the volume and density of renal glomeruli during aging, as well as kidney atrophy. These findings related to oxidative stress clarify many changes occurring in kidney tissues during senescence in rats.

Resumo em Inglês:

Abstract Purpose: To evaluate the effects of meperidine on fascial healing. Methods: Seventy adult male Sprague-Dawley rats divided into 7 groups with 10 rats in each group. One of these groups was determined as the sham group, 3 of the remaining 6 groups as meperidine groups, and 3 as control groups. These were grouped as 1st, 2nd, and 6th weeks. In the anterior abdominal wall of the rat, the skin was detached and a wound model including the peritoneum was created with a median incision. Mice in the meperidine group were injected with meperidine intraperitoneally (IP) 3 × 20 mg/kg meperidine on postoperative days 0, 1 and 2, and 2 × 20 mg/kg meperidine on postoperative days 3, 4, 5, and 6 after surgical intervention. Similar to the control group, an equal volume of saline was administered, corresponding to the doses. After sacrifice, the midline fascia was used for facial tensile strength measurement, and the other for histopathological analysis. Results: When compared, the meperidine and control groups inflammatory cell density was higher in the 1st week (p < 0.05) in the meperidine group, fibroplasia density was found to be higher at the 2nd week in the meperidine group than the control group (p < 0.05) When the tensile strength in the meperidine and control groups were compared, there was no significant difference (p > 0.05) at each of the three weeks. Conclusion: The application of postoperative systemic meperidine affects positively wound healing in the inflammatory stage and fibroplasia without changing the resistance to traction.

Resumo em Inglês:

Abstract Purpose: To develop a model for simulated training of ureteropyelic anastomosis in laparoscopicpyeloplasty. Methods: Longitudinal and experimental study, with 16 participants. A synthetic instrument was produced to simulate the renal pelvis and the proximal portion of the ureter positioned on a platform within laparoscopic simulators, thereby resulting in the realistic simulation of the ureteropelvic anastomosis. A step-by-step guide was also developed for the accomplishment of the ureteropelvic anastomosis training model. Results: In the evaluation of all participants’ suture training, a decrease was found in the time needed to perform the anastomosis, with a median of 17.83 min in the 1st step and 14.21 min in the last one (p = 0.01). Regarding the knots, in the 1st step, 5% of them were considered firm, with an evolution to 30% in the last step (p = 0.011). Conclusion: We noticed improvement in the ability to perform the ureteropelvic anastomosis by participants with no experience with it. Therefore, even unexperienced participants can improve their skills with this training. Moreover, we observed the effectiveness of the model use, confirmed by the participants’ opinion and its validation by expert surgeons.