Suíno como modelo experimental na pesquisa biomédica: valores fisiológicos normais

Background:   The use of animals in biomedical research is of great importance. It is fundamental for the development and improvement of new practices and technologies. The selection of the species must take into consideration the practicality of handling and the suitability for the experiment, and it must have low operational costs. Swine are important as an experimental model in several experiment areas, because the functionality of many of their organic systems is developed similarly as it is in humans. Swine are animals that become easily stressed. For that reason, their conditioning is necessary to allow the obtainment of data that is closer to normal parameters. This study aims at reporting the physiological values obtained from awake swine, under normal conditions and minimum stress. Materials, Methods & Results: The animals were maintained under ideal environmental conditions, and they were always handled and conditioned by the same persons. Twenty crossbred swine were evaluated, aged between 60 and 90 days and with a body mass ranging between 17 and 25 kg. The parameters considered were cardiac frequency (FC),  emoglobin oxygen saturation (pulse oxymetry – SPO2), respiratory frequency (fR), end tidal carbon dioxide (ETCO2), systolic (PAM), diastolic (PAD) and mean (PAM) arterial pressure and arterial blood gas values – pH, arterial pressure of CO2 (PACO2), arterial pressure of O2 (PAO2), total CO2 (TCO2), base excess (EB), bicarbonate (HCO3) and O2 saturation (SATO2). The experiment was developed in compliance with the Standards of Animal Ethics and Welfare recommended by the National Council on the Control of Animal Experiments and with Law 11.794 of October 2008, being further approved by the Ethics Committee of the Hospital de Clínicas de Porto Alegre. To obtain the FC, fR, ETCO2 and SPO2 values, 20 animal samples were used. FC presented mean values (± standard deviation) of 134 ± 20.67 beats per minute (bpm), showing a maximum value of 180 bpm and a minimum of 103 bpm. The mean fR was 24.5 ± 5.61 breaths per minute (bpm), with a maximum value of 34 bpm and a minimum of 14 bpm, and SPO2 was 96 ± 2.10 %. Moreover, the values obtained in the analysis of exhaled gases showed a ETCO2 at 44.6 ± 5.41 mmHg, with a maximum value of 53 mmHg and minimum value of 34 mmHg. The arterial pressure was obtained from 19 animals, yielding the following values: 135.8 ± 16.29 mmHg for systolic pressure, 81.6 ± 14.10 mmHg for diastolic pressure and 103.3 ± 12.65 mmHg for mean pressure. Samples from 18 animals were used to measure the arterial blood gas. The values obtained were as follows: 7.497 ± 0.019 for Mean pH , 41.7 ± 6.95 mmHg for partial O2 pressure, 90.65 ± 2.5 mmHg for partial CO2 pressure, 32.8 ± 2.18 mmol/L for total CO2, 7.57 ± 1.9 mmol/L for base excess, 31.5 ± 2.12 mmol/L for bicarbonate and 97.55 ± 0.64 for oxygen saturation. Discussion: The animals seemed submissive and able to be conditioned and therefore it was easy to obtain basal values. These data were slightly different from the values obtained in other studies, thus becoming more reliable to be used as parameters in exsperiments employing this species. There seem to be interspecies differences when one intends to make a comparison with human beings. Values such as O2 concentration in arterial blood are normally lower in swine, possibly due to a lower hemoglobin concentration and a higher body temperature in the species. Despite some differences, there are many physiological similarities with human beings, which allows for the conclusion that swine is a great species to be employed in the biomedical research

Linfangiectasia intestinal associada à linfangite lipogranulomatosa em cão da raça Pit Bull

A linfangiectasia é uma enteropatia desperdiçadora de proteínas, que ocorre devido à drenagem ineficaz da rede linfática, podendo estar acompanhada por uma linfangite lipogranulomatosa, que é a reação ao material de vasos linfáticos que se romperam. Através dos sinais clínicos, que incluem diarréia crônica, efusões cavitárias, edema de membros e emagrecimento progressivo, em conjunto com achados histopatológicos, se obtém o diagnóstico. Este estudo tem como objetivo descrever os aspectos clínicos e patológicos de um caso de linfangiectasia intestinal associada à linfangite lipogranulomatosa em um cão macho, 14 meses de idade, da raça pit bull, que foi atendido no Hospital de Clínicas Veterinárias da Universidade Federal do Rio Grande do Sul. O animal apresentava aumento abdominal, dispnéia, anorexia e cansaço. Em punção abdominal e torácica, observou-se um líquido esbranquiçado classificado, após análise, como quilo. Optou-se, então, pela laparotomia exploratória para identificação de possíveis causas para a alteração, mostrando obstrução do linfonodo mesentérico e pequenos nódulos brancos e irregulares na serosa do intestino delgado. Foi instituído o tratamento com dieta hipocalórica; porém, o paciente acabou indo a óbito decorridas três semanas de tratamento. Aliando-se os sinais clínicos aos exames laboratoriais e achados de necropsia, chegou-se ao diagnóstico definitivo: linfangiectasia intestinal associada à linfangite lipogranulomatosa

Uso do Laser ALGaInP na cicatrização de lesões cutâneas experimentais em coelhos

Background:  :  :  : Animals with extensive cutaneous lesions remain hospitalized for long periods. In addition to increasing treatment costs, this also causes stress in these animals. Low-power laser is widely used to support tissue repair processes. Its use in the treatment of cutaneous wounds has been studied, as it reduces the wound healing period and the consequences caused by the lesion. The study aimed to evaluat the wound healing process of experimental cutaneous wounds in rabbits with the use of laser therapy. Materials, Methods & Results: Ten healthy New Zealand rabbits were used in the study, which were divided in two groups (n=5). Skin biopsies were carried out on day 16 in Group 1 and on day 8 in Group 2. The animals were under general anesthesia for the experimental cutaneous lesion to be carried out. Two 1cm2 wounds were made on the back of each animal. The lesions were measured by a pachymeter in the immediate postoperative period, then covered with sterile gauze and maintained with rubber bandages. The animals were treated only with Tramadon 3 mg.kg-1 twice a day, during 3 days. Only the lesions on the right side of the animals were irradiated regularly, on each side of the wound, at a distance of 0.5 cm from the margin. The equipment used was a 660nm wavelength AlGaInP laser diode (Laserpulse, Ibramed), pulsed at a frequency of 20 Hz, at a dose of 3J and stimulation time of 12s. The left-side lesions represented the control and the treatment administered to them consisted only of a cleanse using a NaCl solution at 0.9% once a day. The measurement of the lesion area was made every two days with a pachymeter, and the macroscopic characteristics were noted on a control card. For the histological evaluation of the wound healing process, biopsy specimens were taken from the right and left lesions on the sixteenth day in G1 and on the eighth day in G2, by means of a 6mm punch. The samples were stained with Hematoxylin-eosin for the global evaluation of the tissue section, and with Masson’s trichrome for evaluation of the presence of collagen fibers in interstitial fibrosis sites. Hyperemia followed by a discreet bleeding could be observed in wounds treated with laser after its application. With regard to the wound healing area, there was no difference between treated and control animals in both groups. However, in the microscopic evaluation of G1, in relation to the histological variables, significantly higher results were found in lesions treated with laser however, in the microscopic evaluation of G1, in relation to the histological variables, significantly higher results were found in lesions treated with laser: vascular proliferation, fibroblast and collagen proliferation, as well as the presence of hair follicles. In G2, only the fibroblastic proliferation showed a significant difference (p= 0.08) in lesions treated with laser. Discussion: There was no difference in the number of inflammatory cells in this study, perhaps because the control animals underwent laser treatment of the contralateral lesion. However, the treated animals had a higher number of deposited collagen fibers than the control ones, corroborating the data mentioned in literature. The most important result found was associated with vascular proliferation, which showed a significant difference (p= 0.046). The formation of new blood vessels seems to be substantially facilitated by the laser use, because a relatively higher number of elements was found in the group irradiated by it, as similarly hyperemia and bleeding were observed during treatment. The results obtained suggest that irradiation with AlGaInP diode laser, at a dose of 3J, acted as a biostimulative agent in the wound healing of experimental lesions. Evidence of this could be demonstrated by an accelerated cell proliferation process during the experiment. The experimental lesion, animal species selected and laser application method were adequate for the execution of this project

Treatment of canine multicentric lymphoma through vascular access port vs. peripheral venous catheter

Background: Vascular access port (VAP) was developed for the administration of chemotherapeutic agents, minimizing local drug reactions and complications associated with migration of peripheral venous catheter (PVC) in humans. The device is widely used in human oncology and has gained importance in veterinary oncology, especially in long treatment regimens, as in the case of canine lymphoma. VAP favors therapy and the animals life quality. The aim of this study was to describe the use of VAP in dogs, comparing to PVC access, during canine lymphoma chemotherapeutic treatment. Materials, Methods & Results: Eleven dogs with multicentric lymphoma which required chemotherapy were selected for the study. The dogs were randomly allocated to two groups with five and six animals, and each group received the chemotherapy protocol through the PVC (n= 5) or VAP (n= 6). For the sake of standardization, assessments were made whenever the dogs received vincristine sulfate, despite the use of the infusion system in all sessions of the Madison- Wisconsin protocol. A VAP was implanted into the right external jugular vein of six dogs under inhalational anesthesia, using the Seldinger technique. Systolic blood pressure (SBP) levels and handling time during chemotherapy sessions were compared in both groups in three time periods during the procedures: 10 min after arrival to each chemotherapy (P1); immediately after placement of the PVC or puncture of the VAP reservoir (P2); and at the end of chemotherapy (P3). The arithmetic mean of five consecutive assessments was used in each time period. In the chemotherapy sessions, the mean of SBP variation decreased statistically significant in the VAP group compared to PVC group. SBP decreased from P1 to P2 and from P1 to P3 in all sessions (S1, S2, and S3) in the VAP group, and increased in the PVC group. The handling time of VAP group was 110.6 ± 8.4 s, compared to 219.2 ± 24.7 s (mean ± standard error) in the PVC group, showing statisti¬cally significant difference (P < 0.001). VAP surgical implantation time averaged 37 min, decreasing gradually from the first (55 min) to the last patient (21 min). Discussion: SBP levels suggest that the VAP group was calmer from the beginning to the end of the sessions, showed lower SBP levels, and required shorter handling time than did the PVC group. Blood pressure is one of the most objec¬tive ways to assess welfare or stress in dogs. When dog feels threatened or scared, its body automatically enters a state of emergency and, among several changes, blood pressure increases. VAP surgical implantation in dogs have easy learning, as previously described, proven by implantation time progressive reduction. The Seldinger technique is the method of choice for catheter implantation in humans. Dissection of the jugular vein is an alternative, however, the technique with a single incision and venipuncture is less invasive than its modifications. The jugular vein was used because is the site of choice for central accesses in veterinary practice, with a shorter path to the right atrium and smaller rates of catheter mis¬placement, reducing the risk of pneumothorax, venous thrombosis, and pinch-off syndrome. VAP surgical implantation in dogs have easy learning, proven by the implantation time progressive reduction. The study confirmed that VAP promoted animal welfare, shortened chemotherapy sessions, and caused less discomfort to dogs treated for multicentric lymphoma, as indicated by the reduction in SBP, when compared to the PVC group

Osteossíntese de tíbia com fixador esquelético externo em um cordeiro

Entre os avanços que a clínica e cirurgia veterinária apresentaram nos últimos anos, o tratamento de fraturas em grandes animais pode ser citado como um exemplo. A experiência, consolidada em outras espécies de menor porte, permite a tentativa de extrapolar a mesma para as espécies de maior porte, adequando-se sempre às características e particularidades de cada espécie. Atualmente, devemos considerar o tratamento de fraturas de animais de produção como uma forma de evitar o seu descarte, uma vez que, quando se trata de um animal reprodutor, devemos ter a opção de tratá-lo ao invés de decidir pela eutanásia. O presente estudo relata um caso de fratura transversa de diáfise de tíbia de membro posterior esquerdo em um cordeiro sem raça definida, com duas semanas de idade, com histórico de pisoteamento por um bovino. Foi utilizada fixação esquelética externa tipo II para a osteossíntese, obtendo-se eficiente estabilização da fratura. O animal ficou hospitalizado durante todo o período de pós-operatório e a consolidação óssea foi obtida em 30 dias

Condrossarcoma mixóide em um coelho

Tumores ósseos primários em animais, com exceção dos osteossarcomas, são raros. O condrossarcoma é uma neoplasia maligna, de crescimento lento, proveniente de tecido cartilaginoso. É um tumor localmente invasivo, tendo grande propensão a recidivas, mas baixa incidência de formação de metástases. O diagnóstico definitivo é dado pelo exame histopatológico. A remoção cirúrgica, com obediência aos preceitos da cirurgia oncológica é o tratamento indicado. Foi atendido, no Hospital de Clínicas Veterinárias da Universidade Federal do Rio Grande do Sul, um coelho, sem raça definida (SRD), macho, não castrado, com aproximadamente três anos de idade e 4,3kg de peso, apresentando claudicação e aumento de volume na região distal do membro pélvico direito. O exame histopatológico revelou diagnóstico de condrossarcoma mixóide de grau II. Realizou-se a amputação do membro afetado. O paciente demonstrou uma boa recuperação dos movimentos nos primeiros dias após a cirurgia, retornando às funções que realizava anteriormente, como caminhar, correr e saltar

Allogeneic bone graft devitalized in liquid nitrogen - sheep experimental study

O objetivo do trabalho foi avaliar a taxa e a forma de incorporação do aloenxerto ósseo cortical, submetido ao congelamento em nitrogênio líquido e inserido em tíbias de ovelhas. Foram utilizadas seis ovelhas clinicamente sadias que, aos pares, foram simultaneamente submetidas à ostectomia da diáfise tibial para a retirada de um segmento de 7cm que, após a desvitalização em nitrogênio líquido, foi implantado imediatamente no outro paciente e fixado com placa de compressão dinâmica (PCD) e parafusos corticais. Realizaram-se avaliações clínicas e radiográficas, imediatamente e a cada 30 dias, até o 180º dia de pós-operatório. Aos 180 dias, foi realizada eutanásia e coletouse a tíbia direita para avaliação histopatológica. Aos 60 dias de pós-operatório, foi observado o uso funcional do membro operado, sendo a união radiográfica das interfaces proximal e distal verificadas, em média, aos 95 dias. Com isso, pôde-se concluir que o nitrogênio líquido é um método adequado de desvitalização de aloimplantes ósseos corticais de ovelhas, proporcionando altas taxas de incorporação óssea, em média, aos 95 dias de pósoperatório.This study evaluated the allogeneic cortical bone graft incorporation after submission of the harvested fragment to a bout freezing in liquid nitrogen. Six adult sheep, clinically healthy, were submitted to a 7cm ostectomy of the tibial diaphysis. The fragment was submersed in a liquid nitrogen and implanted in another sheep missing a same-sized segment at the corresponding bone. Stabilization of the allograft in the host bone was accomplished by a dynamic compressive plate (DCP). Clinical and radiographic evaluations were performed in the immediate postoperatory period and in every 30 days for six months after surgery. The proximal and distal host-graft interfaces showed radiographic union at a mean postoperative time of 95 days in all the animals. The cortical bone allograft submitted to liquid nitrogen freezing provided adequate bone healing in the sheep model

Mesenchymal stem cells applied to the inflammatory and proliferative phases of wound healing

A cicatrização de feridas é um processo que requer a interação de várias células da derme e epiderme. O objetivo deste trabalho foi avaliar qual o momento da aplicação das células das ADSCs em feridas cutâneas agudas que faria diferença na cicatrização nos primeiros sete dias da lesão. As células-tronco foram isoladas do tecido adiposo de camundongos C57Bl/6 GFP+. Para tanto, foram utilizados 49 camundongos C57Bl/6, divididos em quatro grupos: grupo I (GI/controle; n=14); grupo II (GII; n=14): ADSCs injetadas no d0; grupo III (GIII; n=14): ADSCs injetadas no terceiro dia; e Grupo IV (GIV; n=7): ADSCs injetadas no quinto dia. As avaliações clínicas ocorreram nos dias zero, três, cinco e sete, e as histopatológicas nos dias cinco e sete. Na metodologia proposta, foi observado que o uso de ADSCs aumenta a vascularização, a formação de tecido de granulação, a colagenização e incrementa o número de folículos pilosos em apenas sete dias de avaliação. Além disso, o momento da aplicação das células não repercutiu diferenças significativas nas fases inflamatória e proliferativa do processo de cicatrização das feridas cutâneas.Wound healing is a process that requires the interaction of various cells in the dermis and epidermis. The aim of this study was to evaluate the action of ADSCs in the treatment of acute wounds in order to understand if application time of the cells results in a difference in healing the first seven days of injury. The stem cells were isolated from adipose tissue of C57BL / 6 mice GFP +. Thus, we used 49 mice C57BL / 6 divided into four groups: Group I (GI / control, n=14); Group II (GII; n=14): ADSCs injected to the d0; Group III (GIII; n=14): ADSCs injected on the 3rd day, and Group IV (GIV; n=7): ADSCs injected day 5(d5). Clinical evaluations were performed on days 0, 3, 5 and 7 and the histopathology on days 5 and 7. In the proposed methodology, the use of ADSCs increased vascularization, formation of granulation tissue, collagen deposition and increases the number of hair follicles in just seven days of evaluation. In addition, the time of application of the cells did not affect significant differences in the inflammatory and the proliferative phase of wound healing skin