TGF-ß1 and CD68 immunoexpression in capsules formed by textured implants with and without mesh coverage: a study on female rats

Purpose: To evaluate fibrosis formation and number of macrophages in capsules formed around textured implants without and with mesh coverage. Methods: Fibrosis was analyzed through transforming growth factor-beta 1 (TGF-ß1) immunomarker expression and the number of macrophages through CD68 percentage of cells in magnified field. Sixty female Wistar rats were distributed into two groups of 30 rats (unmeshed and meshed). Each group was then subdivided into two subgroups for postoperative evaluation after 30 and 90 days. The p value was adjusted by Bonferroni lower than 0.012. Results: No difference was observed in fibrosis between meshed and unmeshed groups (30 days p = 0.436; 90 days p = 0.079) and from 30 to 90 days in the unmeshed group (p = 0.426). The meshed group showed higher fibrosis on the 90th day (p = 0.001). The number of macrophages was similar between groups without and with mesh coverage (30 days p = 0.218; 90 days p = 0.044), and similar between subgroups 30 and 90 days (unmeshed p = 0.085; meshed p = 0.059). Conclusions: In the meshed group, fibrosis formation was higher at 90 days and the mesh-covered implants produced capsules similar to microtextured ones when analyzing macrophages. Due to these characteristics, mesh coating did not seem to significantly affect the local fibrosis formation.

Microsurgical arterial anastomosis in young and adult rats: an evolutive and comparative study

Purpose: To evaluate the caliber of an arterial micro-anastomosis in the young growing animal using a continuous suture technique. Additionally, late morphological changes and blood flows distal to the anastomosis were evaluated. Methods: Seventy-four Wistar rats were submitted to laparotomy to access the aorta for blood flow measurement. The aorta was sectioned using microsurgery technique and an end-to-end anastomosis with continuous suture. After a period of six months to one year, the anastomosis was checked. Results: Regarding the size of the aortas, comparing the pre- and postoperative values, there was an increase of 13.33% in adult animals and 25% in young animals, without any difference in the blood flows. Conclusions: The arteries of young rats show signs of growth at the site of the anastomosis performed with continuous suture.

Effect of Botulinum Toxin-A Injected to Muscle Tissue on Perfusion and Survival of Fasciocutaneous Single Perforator-pedicled Propeller Flap in Rats

Background: In plastic surgery practice, fasciocutaneous single-perforator-pedicled propeller flap is a preferred procedure; however, its survival rate is below than expected, especially in flaps with a big rotation arc. When botulinum toxin-A is injected into the muscle tissue that the perforator pedicle is arisen, the tonus of pertinent muscle can reduce and the blood flow of its perforator pedicle can increase. Therefore this procedure can improve the survival rate of single-perforator-pedicled propeller flap. Aims: To evaluate the effect of botulinum toxin-A injected with ultrasonographic guidance into the muscle tissue that the perforator pedicle is arisen from one month ago on the perfusion of flap scintigraphically and the survival rate of single-perforator-pedicled propeller flap in a rat model. Study Design: Animal experiment. Methods: Three study groups were receiving botulinum toxin-A (16 IU-0.4 mL), normal saline (0.4 mL), and no study drug one month ago before flap surgery. Injections were performed under ultrasonography guidance. Flaps were elevated fasciocutaneously over the right 2nd perforator pedicle, under the corneous, with a surgical loupe and microsurgery tool and were rotated clockwise 180°. Then the scintigraphic measurements were obtained after flap elevations in the study groups, including the whole-body and flap perfusions in the study rats. The involvement rate presents the ratio of flap perfusion to whole-body perfusion. Flaps were sutured back to the abdominal wall at the latest twisting angles. With standard photographs taken in all the groups on day 8 after the operation, whole and necrotic flap areas were calculated. Results: Scintigraphically the involvement rate (the ratio of flap perfusion to whole-body perfusion) of the flaps in the botulinum toxin-A group were found significantly higher than those in the other groups (p<0.05). The area of a flap in the botulinum toxin-A group on day 8 post flap suturing was found to be significantly higher than those in the other groups (p<0.05). The area of a necrosis and the percentage of necrosis on day 8 post flap suturing in the botulinum toxin-A group was found significantly lower than those of the sham and null groups (p<0.05). Conclusion: In a rat model, if with the ultrasonographic guidance, botulinum toxin-A is injected to the muscle which perforator of the prospective single-perforator-pedicled propeller flap originated and flap surgery is performed one month later after this injection, the perfusion of single-perforator-pedicled propeller flap increases scintigraphically and this improves flap survival and reduces its necrosis.

Establishing a successful rat model of duodenal- jejunal bypass: A detailed guide.

Gastric bypass surgery, an operation that restricts the stomach and bypasses the duodenum and part of the jejunum, results in major improvement or remission of type 2 diabetes. Duodenual-jejunal bypass was developed by one of the authors (FR) as an experimental, stomach-sparing variant of gastric bypass surgery to investigate weight-independent mechanisms of surgical control of diabetes. Duodenual-jejunal bypass has been shown to improve various aspects of glucose homeostasis in rodents and in humans, thus providing an experimental model for investigating mechanisms of action of surgery and elusive aspects of gastrointestinal physiology. Performing duodenual-jejunal bypass in rodents, however, is associated with a steep learning curve. Here we report our experience with duodenual-jejunal bypass and provide practical tips for successful surgery in rats. Duodenual-jejunal bypass was performed on 50 lean rats as part of a study aimed at investigating the effect of the procedure on the physiologic mechanisms of glucose homeostasis. During the study, we have progressively refined details of anatomic exposure, technical aspects of duodeno-jejunostomy and peri-operative care. We analysed the role of such refinements in improving operative time and post-operative mortality. We found that refinement of exposure methods of the gastro-duodenal junction aimed at minimizing tension on small visceral vasculature, technical aspects of duodeno-jejunal anastomosis and peri-operative management played a major role in improving the survival rate and operative time. Overall, an experimental model of duodenual-jejunal bypass was successfully reproduced. Based on this experience, we describe here what we believe are the most important technical tips to reduce the learning curve for the procedure.

Preliminary study on the biocompatibility and osteoconductive properties of a new bovine bone graft / Estudio preliminar sobre las propiedades de biocompatibilidad y osteoconductividad de un nuevo injerto de hueso bovino

To prevent post-extraction resorption and preserve the integrity of the alveolar ridges, the placement of bone grafts at the time of extraction is recommended. Bovine bone grafts are biocompatibile and osteoconductive, allowing new bone apposition by osteoprogenitor cells. Although there are trademarks recognized internationally regarding bovine bone grafts, they are expensive and even difficult to acquire. Therefore, domestic industry development of high quality biomaterials will reduce the public health high costs in the dental field. Here, we evaluated and compared the effects of an Argentinean manufactured bovine bone graft (Synergy Bone Matrix) with a bovine bone graft recognized for its osteoconductive effects (Bio-Oss), on bone healing in an experimental model in rats. We created critical sized bone defects in rat tibiae and filled them with either one of the bovine bone grafts or control. Clinical responses, X-ray findings, bone mineral density, and histological parameters were evaluated. No abscess, encapsulation, suppuration or inflammation of lymphatic nodes were observed. Radiographically, all implants were amalgamated to the surrounding bony margins, suggesting proper healing. On the other hand, control tibiae exhibited no signs of recovery and remained either unfilled or showed fibrous tissue formation. No statistical differences were observed in BMC and BMD between tibiae filled with Synergy Bone Matrix or Bio-Oss. Histological analysis revealed particles of both bone grafts surrounded by laminar bone tissue indicating osteoconductivity, without any inflammatory sign. This preliminary study suggests that Synergy Bone Matrix, as well as Bio-Oss, present similar properties of biocompatibility and osteoconductivity. (AU)

Para prevenir la resorción post-exodoncia y preservar la integridad de los rebordes alveolares, se recomienda la colocación de injertos óseos en el momento de la extracción. Los injertos de hueso bovino son biocompatibles y osteoconductivos, permitiendo nueva aposición ósea por células osteoprogenitoras. Existen marcas internacionales de injertos de hueso bovino, pero resultan caros e incluso difíciles de adquirir. Por ello, la elaboración de biomateriales de alta calidad, nacionales, reduciría los altos costos de salud pública en odontología. En este estudio, se evaluaron y compararon los efectos de un injerto de hueso bovino fabricado en Argentina (Synergy Bone Matrix) versus un injerto de hueso bovino reconocido por sus efectos osteoconductivos (Bio-Oss), en el proceso de cicatrización ósea en un modelo experimental en ratas. Para ello, creamos un defecto óseo crítico en tibia de rata el cual se rellenó con uno de los injertos de hueso bovino o control. Se evaluó: respuesta clínica y radiográfica, densidad mineral ósea e histología. No se observaron abscesos, encapsulación, supuración o inflamación de los ganglios linfáticos. Radiográficamente, todos los implantes se integraron a los márgenes óseos circundantes, sugiriendo una cicatrización adecuada. Por el contrario, las tibias control no mostraron signos de recuperación con formación de tejido fibroso. No se observaron diferencias estadísticas en las BMC y BMD entre las tibias Synergy Bone Matrix o Bio-Oss. La histología reveló partículas de ambos injertos óseos rodeadas por tejido óseo laminar indicando osteoconductividad sin signos inflamatorios. Este estudio preliminar sugiere que Synergy Bone Matrix presenta propiedades similares de biocompatibilidad y osteoconductividad que Bio-Oss. (AU)

Retroauricular Approach for Targeted Cochlear Therapy Experiments in Wistar Albino Rats.

BACKGROUND: As the idea of stem cell technology in the treatment of sensorial hearing loss has emerged over the past decades, the need for in vivo models for related experiments has become explicit. One of the most common experimental models for inner ear stem cell delivery experiments is the Wistar albino rat. AIMS: To investigate the surgical anatomy of the temporal bone of the Wistar albino rat with respect to the dissection steps, operative techniques and potential pitfalls of surgery. STUDY DESIGN: Animal experimentation. METHODS: Adult Wistar albino rats were operated on via the retroauricular approach under an operation microscope. The anatomy of the temporal bone, the surgical route to the temporal bulla and the inner ear were investigated. Technical details of surgical steps, complications and potential pitfalls during the surgery were noted. RESULTS: The study group consisted of 40 adult Wistar albino rats. The mean times to reach the bulla and to achieve cochleostomy were 4.3 (2-13 min) and 7.5 min (3.5-22 min), respectively. The mean width of the facial nerve was 0.84 mm (0.42-1.25 mm). The stapedial artery lay nearly perpendicular to the course of the facial nerve (88-93 °C). There were three major complications: two large cochleostomies and one massive bleed from the stapedial artery. CONCLUSION: The facial nerve was the key anatomical landmark in locating the bulla. By retrograde tracing of the facial nerve, it was possible to find the bulla ventral (inferior) to the main trunk. The facial nerve trunk was the upper limit when drilling the bulla. By dissecting the main trunk of the facial nerve and retracting cranially, a large drilling space could be achieved. Our results suggest that the retroauricular approach is an effective, feasible route for inner ear drug delivery experiments in Wistar albino rats.

Prevention of Intraabdominal Adhesions: An Experimental Study Using Mitomycin-C and 4% Icodextrin.

BACKGROUND: Intraabdominal adhesions remain a significant cause of morbidity and mortality. Moreover, intraabdominal adhesions can develop in more than 50% of abdominal operations. AIMS: We compared the anti-adhesive effects of two different agents on postoperative adhesion formation in a cecal abrasion model. STUDY DESIGN: Experimental animal study. METHODS: Forty Wistar albino type female rats were anesthetized and underwent laparotomy. Study groups comprised Sham, Control, Mitomycin-C, 4% Icodextrin, and Mitomycin-C +4% Icodextrin groups. Macroscopic and histopathological evaluations of adhesions were performed. RESULTS: The frequencies of moderate and severe adhesions were significantly higher in the control group than the other groups. The mitomycin-C and Mitomycin-C +4% Icodextrin groups were associated with significantly lower adhesion scores compared to the control group and 4% Icodextrin group scores (p=0.002 and p=0.008, respectively). The adhesion scores of the Mitomycin-C group were also significantly lower than those of the 4% Icodextrin group (p=0.008). CONCLUSION: Despite its potential for bone marrow toxicity, Mitomycin-C seems to effectively prevent adhesions. Further studies that prove an acceptable safety profile relating to this promising anti-adhesive agent are required before moving into clinical trials.

A laparoscopic technique of partial hepatectomy in the rat.

BACKGROUND: Laparoscopic partial hepatectomy is an increasingly applied technique in the treatment of liver tumors and in living donor transplantation. There is a need for establishing an animal model that would facilitate experimental research on the technique. The aim of the present study was to describe a safe and efficient laparoscopic technique of 70% partial hepatectomy in the rat. MATERIALS AND METHODS: Twenty-four male Wistar rats underwent either laparoscopic (group LAP-HEP) or open resection of the median and left lateral hepatic lobes (group HEP). In group LAP-HEP, a 5-mm Hg pneumoperitoneum was established. Three 5-mm trocars were introduced in the abdominal cavity. A self-made pretied ligature loop was used to ligate en bloc the pedicles of the hepatic lobes to be resected. A self-made sterile elastic specimen retrieval bag facilitated extraction of the resected liver tissue. In group HEP, the same liver lobes were resected by ligation of their pedicles after midline laparotomy. RESULTS: The percentage of resected liver parenchyma did not differ between groups. All animals returned to normal feeding activity by 48 h postoperation and had no complications. CONCLUSIONS: A simple, cost-effective, safe, and efficient laparoscopic technique for 70% partial hepatectomy in the rat was described.

Tobacco smoke exposure induces irreversible alteration of testicular function in prepubertal rats.

BACKGROUND: Smoking is a serious public health problem and an important risk factor of many diseases. The present study evaluated whether or not the influence of prolonged tobacco smoke (TS) exposure on spermatic indices and reproductive hormones would be reversible in young and adult rats. METHODS: Prepubertal and adult rats were grouped into five (I, II, III, IV, and V) separately (n=5/group) and exposed to TS at target concentrations of 0, 0.5, 1.0, 0.5, and 1.0 mg nicotine/day, respectively for 30 days using the whole body exposure inhalation method. Groups I, II, and III were sacrificed 24 h after TS exposure, while groups IV and V were allowed to recover for 30 days before they were sacrificed. RESULTS: Sperm count and motility were significantly (p<0.05) reduced in exposed prepubertal and adult rats. Additionally, sperm morphology was unaltered, testosterone was reduced, while luteinizing hormone (LH) and follicle stimulating hormone (FSH) were elevated compared to the non-TS exposed control group. The reductions in sperm count and motility were reversed only in adult recovery rats. LH and FSH elevations were reversed in all recovery animals, but testosterone concentrations remained lower than control. Furthermore, malondialdehyde levels in testes of exposed rats were significantly increased. This was reversed only in adult recovery rats that received 0.5 mg nicotine. Testicular levels of catalase, reduced glutathione, and superoxide dismutase were unaltered, except in prepubertal rats wherein catalase was decreased in both treated and recovery groups. CONCLUSIONS: The TS exposure alters sperm characteristics reversibly in adult, but irreversibly in prepubertal rats, which is attributable to elevation of oxidative stress.

Aplicação da membrana de látex natural e do extrato da pele de rã (Lithobates catesbiana) em feridas cirúrgicas cutâneas de ratos Wistar / Application of natural latex membrane and extract of frog skin (Lithobates catesbiana) (Shaw, 1802) in cutaneous surgical wounds of Wistar rats

Implantou-se a membrana de látex natural e o extrato da pele de rã individualmente e em conjunto em feridas cutâneas de ratos com o intuito de se avaliar o processo de reparação tecidual e possíveis complicações. Utilizou-se 60 ratos da linhagem Wistar divididos em grupos experimentais: grupo controle (GC), grupo membrana de látex (GM), grupo óleo do extrato da pele de rã (GO) e grupo membrana de látex e óleo de rã (GMO), cada um com 15 animais. Aos três, cinco, sete, 14 e 21 dias de pós-operatório, foi realizada eutanásia dos animais para avaliações macroscópicas e histológicas da região lesionada. Nas feridas dos animais do GM e do GC a cicatrização ocorreu mais cedo, no último tempo de avaliação o sinal de lesão era mínimo, já no GMO, a cicatrização não foi completa e no GO a ferida teve o pior resultado, com presença de crosta no 21º dia. Foram observadas, à microscopia de luz, células normais envolvidas no processo de reparação tecidual e formação de neovasos em todos os grupos.  Conclui-se que em todos os grupos não houve rejeição dos biomateriais testados, todavia o grupo GM proporcionou melhor cicatrização com menos efeitos adversos quando comparada aos demais grupos testados.

In this study, the membrane of the natural latex and extract of the skin frog, isolated and together, where implanted to replacea cutaneous in the mice, with purpose for evaluating the tissue repair process and possible complication. Sixty Wistar rats eredivided in four experimental groups: control group (GC), membrane of the latex group (GM), oil of the frog group (GO) and groupmembrane of latex with oil of the frog group (GMO), each one with 15 animals. The animals were euthanized at three, five, seven,14 and 21 days post-operative, followed by macroscopic and microscopic evaluations of the area of the lesion. In the wounds ofthe GM and GC, healing occurred earlier, in the latter evaluation time the signal was minimal injury, in the GMO healing was notcomplete and the wound GO had the worst outcome with presence of crust on the 21st day. There were observed by microscopic,normal cells involved in the tissue repair process and neovascularization in all groups. We conclude that in all groups there wasno rejection of the biomaterials tested, however the GM group gave better healing with fewer adverse effects when compared to the other groups tested.

Wistar rats from different suppliers have a different response in an acute myocardial infarction model.

The Wistar rat is a commonly used strain for experimental animal models. Recently it was shown that results vary between studies using Wistar rats of different suppliers. Therefore we studied whether Wistar rats obtained from Harlan Laboratories (Ha, n=24) and Charles River (CR, n=22) had a different outcome in an acute myocardial infarction (AMI) model. AMI was induced in both Ha and CR Wistar rats by one operator. This resulted in a significantly higher survival rate for Ha (79.2±10.2%) compared with CR rats (54.2±10.2%, p<0.05). Furthermore, CR rats had lost significantly more weight after 7 days (-5.9±3.1%) compared with Ha rats (-0.8±1.7%; p<0.001), indicating a worse health status of the CR rats. Paradoxically, the induced infarct was smaller in CR rats (7.3±3.6% of the heart) compared with Ha rats (12.1±4.7%, p<0.05). This indicates that CR rats were less sensitive for the cardiomyocyte damage subsequent to AMI induction, but remarkably showed more clinical side effects indicating that Wistar rats from two suppliers had a different response within the same AMI model.

Temperatura de polimerização da resina acrílica odontológica na medula espinhal de ratos Wistar / Polymerization temperature of dental acrylic resin in the spinal cord of rats

Objetivou-se investigar se a temperatura de polimerização da resina acrílica odontológica ocasiona sinais neurológicos e alteração histológica na medula espinhal de ratos. Foram utilizados 48 ratos, Wistar, distribuídos em dois grupos denominados GI ou cimento ósseo (controle positivo) e GII ou resina acrílica odontológica. Cada grupo foi redistribuído em seis subgrupos, de acordo com a quantidade do composto, o tempo de pós-operatório e o local de aferição da temperatura. O cimento ósseo ou a resina acrílica odontológica foram moldados e colocados sobre as lâminas ósseas dorsais e os processos espinhosos das vértebras L1 e L2. A temperatura de polimerização do composto foi aferida a cada 10 segundos. A temperatura máxima de polimerização e a diferença entre a temperatura externa e a interna ao canal vertebral foram maiores nos subgrupos que receberam 10 gramas. Não foi observada alteração neurológica em nenhum dos animais deste estudo. Na análise histológica, foi observada reação inflamatória de intensidade variável na meninge e no parênquima medular. Pode-se concluir que a temperatura de polimerização da resina acrílica odontológica nas quantidades de um e 10 gramas provoca alterações histológicas na meninge e no parênquima medular, sem ocasionar sinais neurológicos em ratos.

The purpose of this study was to evaluate if the polymerization temperature of the dental acrylic leads to neurological signs and histological changes in the rat spinal cord. Forty eight rats were distributed in two groups: GI or bone cement (positive control) and GII or dental acrylic resin. Each group was redistributed in six subgroups according to compound quantity, postoperative period and location of temperature measurement. The bone cement or dental acrylic resin were molded and positioned on the bony lamina and the dorsal spinous processes of vertebrae L1 and L2. The polimerization temperature was measured every 10 seconds. The polymerization maximum temperature and the temperature difference between internal and external spinal canals were superior in subgroups that received 10 grams. There were no neurological deficits in any animal of this study. The histological analysis showed intensity variation of inflammatory reaction in the meninges and spinal cord parenchyma. The results demonstrate that the polymerization temperature of dental acrylic resin in quantity of 1 or 10 grams causes histological changes in the spinal cord parenchyma and meninges, without neurological deficits in rats.

Inducción de endometriosis en rata Wistar, mediante autotransplante de fragmento uterino, sobre cicatriz previamente producida en el cuerno uterino izquierdo / Induction of endometriosis in Wistar rats through autologous transplantation of a uterine fragment over a previous scar in the left uterine horn

Objetivo. Estudiar la posibilidad de inducir endometriosis interna/externa en rata wistar, a través de un nuevo modelo microquirúrgico, que denominamos PGR 1. Sujetos y métodos. Se han utilizado 11 ratas Wistar, a las que se ha realizado un autotransplante de fragmento uterino, sobre la cicatriz resultante de la cirugía necesaria para su obtención. Después de 8 semanas se les practicó una nueva intervención, para la inspección de la cavidad abdominal y la toma de muestras relevantes para su estudio anatomopatológico. Resultados. Macroscópicos: adherencias que afectaban fundamentalmente a la zona del implante; vesículas amarillentas. Microscópicos: vesículas/quistes; fenómenos inflamatorios; neovascularización; endometriosis interna en un animal. Conclusiones. Este nuevo modelo de implante nos puede ayudar a comprender mejor los mecanismos involucrados en la aparición de endometriosis, tanto interna como externa (AU)

Objective. To study the possibility of inducing internal or external endometriosis in Wistar rats through a new microsurgical model known as PGR 1. Subjects and methods. Eleven Wistar rats underwent autologous transplantation of a uterine fragment over a deliberately created scar. After 8 weeks, a further intervention was carried out to inspect the abdominal cavity and take samples for pathological analysis. Results. Macroscopic results consisted of adhesions mainly affecting the implant and yellow vesicles. Microscopic findings consisted of vesicles/cysts, inflammatory phenomena, neovascularization, and internal endometriosis in one animal. Conclusions. This new implant model could enhance our understanding of the mechanisms involved in the development of endometriosis, both internal and external (AU)

El trasplante de astrocitos encapsulados mejoran el déficit motor en la habilidad manual producido por la lesión de la corteza frontal en ratas adultas / Transplant of encapsulated astrocyte ameliorate lesion-induced motor deficits in adults rats with frontal cortex injury

Objetivo: Investigar la capacidad de trasplantes de astrocitos encapsulados en esferas de alginato de recuperar el déficit en la habilidad manual producida por la lesión de la corteza frontal, en ratas adultas. Material y metodología: Se utilizaron ratas Wistar, y se emplearon pruebas conductuales, cultivos celulares, técnica de encapsulación de células y trasplantes. Los animales se condicionaron en un test de habilidad motora fina y se determinó su mano preferente. Se lesionó la corteza frontal contralateral a la mano preferente y se evaluó la efectividad de la lesión mediante el test de conducta. En un grupo de animales lesionados se trasplantó astrocitos encapsulados en esferas de alginato en la cavidad producida por la lesión; en un segundo grupo, se trasplantó tejido cortical fetal; y en un tercer grupo, se implantó esferas de alginato sin células. Resultados: A los tres meses post-trasplante, tanto los animales con trasplantes de astrocitos encapsulados como con trasplantes de tejido cortical mejoraron el déficit motor inducido por la lesión. Los animales con trasplantes de esferas de alginato vacías no experimentaron mejoría. Conclusión: Los trasplantes de astrocitos encapsulados mejoran, a largo plazo, el deficit motor. El alginato indujo efectos secundarios en el huésped (AU)

Objetive: To investigate whether transplants of encapsulated astrocytes in alginate spheres were able to recover the deficit in motor skills produced by frontal cortex lesion, in adult rats. Material and method: Male Wistar rats were used. Behavioral test, tissue culture, astrocyte transplants and immunocytochemical and histological techniques were applied. Animals were conditioned in a paw reaching for food task and the preferred paw determine. Lesion was produced in the frontal cortex contralateral to the preferred paw and the effectiveness of the lesion tested. In one group of lesion animals, encapsulated astrocytes in alginate spheres were implanted in the lesion cavity; in a second group, fetal cortical tissue was used as donor material; while in a third group empty alginate spheres were implanted. Results: Three months after grafting, the rats with encapsulated astrocyte or with fetal cortical tissue transplants ameliorated the lesion-induced motor deficit.The rats with implant of empty alginate spheres showed no improvement. Conclusion: Transplants of encapsulated astrocytes in alginate spheres induce a long- term improvement of motor lesion deficits. The alginate induced long-term side effects on the host (AU)

Sutureless colic anastomoses with cyanoacrylates

BACKGROUND AND AIMS. The present research project has been made mainly with the idea of comparing the tensile strength values and histological answers of three types of colon anatomises: sutured with silk and sutureless anastomoses with 2-octylcyanocrylate and N-butyl-2-cyanoacrylate. METHODS. 112 Wistar rats distributed into three groups of 35 animals and a last control group of 7 have been used for this. Group 1: silk, group 2: 2-octyl-cyanocrylate, group 3: N-butyl-2-cyanoacrylate, group 4: Control group. The following surgical interventions were practiced on them: A cross section of the colon, followed by: group 1: an end-to-end discontinuoussuture anastomoses with Silk; group 2: sutureless anastomoses with 2-octyl-cyanocrylate; group 3: sutureless anastomoses with N-butyl-2-cyanoacrylate. On the 10th, 20th, 30th, 40th and 50th days we proceeded to measure the anastomoses' tensile strength value for each series. In the same period of time we carried out the following anatomic-pathological determinations: a) sharp inflammation; b) oedema; c) non-specific chronic inflammatory infiltrate; d) granulomatous inflammatory infiltrate to foreign bodies; e) fibrosis. RESULTS. The results obtained indicate a greater anastomoses' tensile strength for group 2 and 3. The anatomic-pathological values show a better response to anastomoses with adhesives than with conventional sutures. CONCLUSIONS. All these experimental results lead us to conclude that the cyanocrilates used to carry out sutureless anastomoses may be an alternative to the handmade conventional anastomoses. Moreover they are easy to be implemented (AU)

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Long-term subarachnoid catheter placement in the middle cranial fossa of the rat.

Research using rats sometimes requires long-term placement of catheters in the subarachnoid space, the cavity between the arachnoid mater and the pia mater in the brain. These catheters can be used to experimentally induce subarachnoid bleeding by injecting blood or to locally administer drugs or other substances. To date, published techniques for penetrating the subarachnoid space of small experimental animals require the use of inflexible or relatively inflexible catheters. These catheters typically consist of metal or stiff plastic and are used to access the occipital or frontal cranial cavity or to directly access the cisterna magna via the atlantooccipital membrane. However, inflexible catheters are not ideal for long-term placement in the subarachnoid space. In this paper, the authors describe a reliable procedure for long-term catheterization of the subarachnoid cavity of the rat. For this method, personnel insert the catheter and keep it in place in the rat's middle cranial cavity, in the vicinity of the cerebral arterial circle. This new approach allows personnel to repeatedly use the catheter for a period of at least 2 weeks. The catheter, which is well-tolerated by rats, can be used for administering saline solutions and for injecting blood that has not been treated with heparin into the subarachnoid space.

The use of carrageenan for limiting the mandibular movement in rats: A preliminary experimental study

Purpose: The objective of this study was to evaluate if the carrageenan may be used for limiting the mandibular movement. Material and Methods: Eighteen adult male Wistar rats were used for the research, 20 ìl of carrageenan (4%) was infiltrated in the extra articular region, in front of the condyle to induce fibrosis. The rats were divided into groups according to the time of euthanasia (7, 15 and 30 days). Maximal mouth opening (MMO), mandibular deviation,initial and final weights were recorded and evaluated. After the euthanasia, the specimens were submitted to histological study in order to classify the inflammatory process using scores. Results: The mean differences between initial and final MMO were 1.50 mm, being greatest at the 7 days evaluation and lowest at 30 days, and were not statistically significant at any time. No mandibular deviation was observedat any of the times of evaluation. The histological scores tended to increase with time of evaluation from 7to 30 days, but without progression of the process.Conclusion: The study model permitted the development of fibrosis in the extra-articular region in the majority of the animals (AU)

Imunossupressão com tacrolimus favorece a regeneração hepática induzida por hepatectomia extensa em ratos / Tacrolimus-based immunossupression favours liver regeneration induced by extent hepatectomy in rats

RACIONAL: A regeneração hepática representa o resultado de respostas fisiológicas que ocorrem após perdas de parênquima, como consequência de agressões tóxico-medicamentosas, infecciosas, traumáticas ou cirúrgicas. OBJETIVO: Avaliar, em dois momentos distintos da regeneração hepática, a influência do tacrolimus sobre o fenômeno da regeneração hepática desencadeada pela ressecção de 70

do parênquima hepático em ratos plenamente desenvolvidos. MÉTODO: Utilizaram-se 40 ratos Wistar com peso médio de 510,08 g ± 11.66 g divididos aleatoriamente em dois grupos de 20 (Estudo e Controle), cada grupo subdividido em dois subgrupos conforme o dia da morte após a hepatectomia (24 horas e 7 dias). De acordo com o grupo os animais receberam por gavagem, diariamente, iniciando três dias antes da hepatectomia e prolongando-se por todo o período de observação, solução aquosa de tacrolimus 0,1 mg/kg/dia ou solução salina no mesmo volume. Após três dias de pré-terapia todos foram submetidos à hepatectomia de 70

pela ressecção dos lobos hepáticos mediano e lateral esquerdo que foram pesados para posterior cálculo da regeneração hepática pela fórmula de Kwon. Vinte e quatro horas ou sete dias após a hepatectomia, 10 animais de cada grupo foram mortos, os fígados remanescentes (regenerados) foram pesados e amostrados para realização de índice mitótico por hematoxilina-eosina e estudo imunoistoquímico com os marcadores PCNA e Ki-67. RESULTADOS: Os animais que receberam tacrolimus mostraram índice maior de regeneração hepática, atingindo significância estatística quando comparado ao subgrupo de animais mantidos com placebo quando analisados pelos parâmetros: fórmula de Kwon, índice mitótico e marcador PCNA. A tendência para o marcador Ki-67 foi idêntica aos outros parâmetros, mas não alcançou significância estatística...

BACKGROUND: Liver regeneration is the result of physiological responses that occur after loss of parenchyma, as a consequence of drug abuse-toxic, infection, trauma or surgical procedure. AIM: To analyze, during two different moments of liver regeneration, the effect of the immunosuppressant tacrolimus on the 70

hepatectomy model-induced liver regeneration in adult rats. METHODS: Forty Wistar adult rats, weighing 510.08+11.66 g were randomly divided into two groups (Study or Control), each group divided into two subgroups according to the death day after 70

hepatectomy (24 hours or 7 days). According to the group of study, rats received 0.1mg/Kg/day of tacrolimus or the same volume of saline solution, by gavage, daily, starting three days before hepatectomy until the end of observation (animal death´s day). After three days of pre-therapy, all animals were submitted to 70

hepatectomy by resection of median and left lateral hepatic lobes which were weighed for posterior calculation of liver regeneration by Kwon´s formula. Twenty four hours or seven days after hepatectomy 10 rats of each group were killed; the remaining liver (regenerated) was entirely resected, weighed and sampled for mitotic index on hematoxylin-eosin staining and immunohistochemical assays with PCNA and Ki-67 markers. Data were statistically analyzed by Mann-Whitney or Student "t" tests, with significance level of 5

(P<0.05). RESULTS: Rats receiving tacrolimus showed statistically significant higher levels of liver regeneration when compared to placebo according to Kwon's formula, mitotic index and PCNA marker. Identical trend was found with Ki-67 marker, but without statistical significance. CONCLUSION: Tacrolimus-based immunossuppression has stimulatory effect on liver regeneration process induced by 70

hepatectomy in adult Wistar rats.

Prevenção do estresse oxidativo na síndrome de isquemia e reperfusão renal em ratos com suplementação nutricional com antioxidantes / Prevention of oxidative stress in renal ischemia-reperfusion syndrome in rats with nutritional antioxidant supplementation

OBJETIVO: Verificar o potencial efeito protetor de suplementação com vitaminas antioxidantes em um modelo de síndrome de isquemia-reperfusão renal em ratos. MÉTODOS: Foram utilizados 29 ratos Wistar, divididos em três grupos: Grupo I e II (n=10 cada), submetidos a indução do estresse oxidativo pela aplicação de 60 minutos de isquemia renal, seguidos de 10 minutos de reperfusão; adicionalmente, os animais do Grupo II foram pré-tratados por doze dias com vitaminas antioxidantes (vitamina C 11,43mg/kg e vitamina E 28,57mg/kg) antes da submissão à isquemia; Grupo III (n=9), correspondendo aos animais Sham, que foram manipulados de forma equivalente aos outros grupos, porém sem indução do estresse oxidativo e sem suplementação antioxidante. Findo isso, as amostras de sangue e os rins foram colhidos para avaliação dos níveis do malondialdeído, do ácido úrico e da capacidade antioxidante total. RESULTADOS: Para o malondialdeído e ácido úrico do Grupo I foi observado um aumento estatisticamente significante (p<0,01) em relação ao Grupo III, o qual não apresentou diferença em relação ao Grupo II. Para os níveis de capacidade antioxidante total, foi encontrada uma diminuição nos animais do Grupo I em relação aos Grupos II e III (p<0,01). CONCLUSÃO: Esses dados confirmam não apenas a efetiva participação do estresse oxidativo neste modelo de síndrome de isquemia e reperfusão renal em ratos, como também que o uso de vitaminas antioxidantes, associadas à dieta, pode proteger os animais das alterações oxidativas.

OBJECTIVE: The objective of this study was to verify the potential protective effect of antioxidant vitamin supplementation in a model of renal ischemic-reperfusion injury in rats. METHODS: Twenty-nine Wistar rats were divided into three groups: groups I and II (n=10 each), were submitted to 60 minutes of renal ischemia, followed by 10 minutes of reperfusion; additionally, animals of group II were treated for twelve days with antioxidant vitamins (vitamin C 11.43mg/kg and vitamin E 28.5 mg/kg) before being submitted to ischemia; In group III (n=9), the animals were treated like the other groups but not submitted to ischemic-reperfusion injury and not given antioxidant supplements. Subsequently, blood samples and the kidneys were collected for assessment of malondialdehyde, uric acid and total antioxidant capacity. RESULTS: The malondialdehyde and uric acid of group I was significantly higher than those of group III (p<0.01), which in turn did not differ from group II. The levels of total antioxidant capacity of the animals of group I was lower than those of groups II and III (p<0.01). CONCLUSION: These data confirmed the effective participation of oxidative stress in this model of renal ischemia-reperfusion syndrome in rats and showed that the use of antioxidant supplementation can protect the animals from oxidative changes.