Rat Grimace Scale as a Method to Evaluate Animal Welfare, Nociception, and Quality of the Euthanasia Method of Wistar Rats.

Refinement of experimental procedures in animal research has the objective of preventing and minimizing pain/distress in animals, including the euthanasia period. This study aimed to evaluate pain associated with six methods of euthanasia in Wistar rats (injectable, inhalational, and physical), by applying the Rat Grimace Scale (RGS), comparing the scores, and determining the method with the highest score that might indicate pain for laboratory rodents. Sixty adult male and female Wistar rats were used and assigned to six treatments: pentobarbital, CO2, decapitation, isoflurane, ketamine + xylazine, and ketamine + CO2. Video recording to assess the RGS scores was performed in four events: basal: 24 h before the procedure; Ti1: three minutes before the procedure; Ti2: during the application of the euthanasia method; and Ti3: immediately after the application until LORR. The main findings of this study showed that, during Ti2, decapitation and ketamine + xylazine had the highest scores (0.6 ± 0.26 and 0.6 ± 0.16, respectively) (p < 0.0001), while at Ti3, CO2 (0.9 ± 0.18) and isoflurane (1.2 ± 0.20) recorded the highest scores (p < 0.0001). According to the present results, decapitation and ketamine + xylazine elicited short-term acute pain, possibly due to tissue damage caused by both methods (injection and guillotine). In contrast, isoflurane's RGS scores recorded during Ti3 might be associated with nociception/pain due to the pungency of the drug or to the pharmacological muscle relaxant effect of isoflurane. Further research is needed to establish a comprehensive study of pain during euthanasia, where RGS could be used minding the limitations that anesthetics might have on facial expression.

Novel Therapy for Acquired Tracheomalacia with a Tissue-Engineered Extraluminal Tracheal Splint and Autologous Mesenchymal-Derived Chondrocytes

Abstract Introduction Acquired tracheomalacia (ATM) is characterized by a loss of structural strength of the tracheal framework, resulting in airway collapse during breathing. Near half of the patients undergoing prolonged invasive mechanical ventilation will suffer tracheal lesions. Treatment for ATM includes external splinting with rib grafts, prosthetic materials, and tracheal resection. Failure in the use of prosthetic materials has made reconsidering natural origin scaffolds and tissue engineering as a suitable alternative. Objective To restore adequate airway patency in an ovine model with surgicallyinduced ATM employing a tissue-engineered extraluminal tracheal splint (TE-ETS). Methods In the present prospective pilot study, tracheal rings were partially resected to induce airway collapse in 16 Suffolk sheep (Ovis aries). The TE-ETS was developed with autologous mesenchymal-derived chondrocytes and allogenic decellularized tracheal segments and was implanted above debilitated tracheal rings. The animals were followed-up at 8, 12, and 16 weeks and at 1-year postinsertion. Flexible tracheoscopies were performed at each stage. After sacrifice, a histopathological study of the trachea and the splint were performed. Results The TE-ETS prevented airway collapse for 16 weeks and up to 1-year postinsertion. Tracheoscopies revealed a noncollapsing airway during inspiration. Histopathological analyses showed the organization of mesenchymal-derived chondrocytes in lacunae, the proliferation of blood vessels, and recovery of epithelial tissue subjacent to the splint. Splints without autologous cells did not prevent airway collapse. Conclusion It is possible to treat acquired tracheomalacia with TE-ETS without further surgical removal since it undergoes physiological degradation. The present study supports the development of tissue-engineered tracheal substitutes for airway disease.

Novel Therapy for Acquired Tracheomalacia with a Tissue-Engineered Extraluminal Tracheal Splint and Autologous Mesenchymal-Derived Chondrocytes.

Introduction Acquired tracheomalacia (ATM) is characterized by a loss of structural strength of the tracheal framework, resulting in airway collapse during breathing. Near half of the patients undergoing prolonged invasive mechanical ventilation will suffer tracheal lesions. Treatment for ATM includes external splinting with rib grafts, prosthetic materials, and tracheal resection. Failure in the use of prosthetic materials has made reconsidering natural origin scaffolds and tissue engineering as a suitable alternative. Objective To restore adequate airway patency in an ovine model with surgically-induced ATM employing a tissue-engineered extraluminal tracheal splint (TE-ETS). Methods In the present prospective pilot study, tracheal rings were partially resected to induce airway collapse in 16 Suffolk sheep ( Ovis aries ). The TE-ETS was developed with autologous mesenchymal-derived chondrocytes and allogenic decellularized tracheal segments and was implanted above debilitated tracheal rings. The animals were followed-up at 8, 12, and 16 weeks and at 1-year postinsertion. Flexible tracheoscopies were performed at each stage. After sacrifice, a histopathological study of the trachea and the splint were performed. Results The TE-ETS prevented airway collapse for 16 weeks and up to 1-year postinsertion. Tracheoscopies revealed a noncollapsing airway during inspiration. Histopathological analyses showed the organization of mesenchymal-derived chondrocytes in lacunae, the proliferation of blood vessels, and recovery of epithelial tissue subjacent to the splint. Splints without autologous cells did not prevent airway collapse. Conclusion It is possible to treat acquired tracheomalacia with TE-ETS without further surgical removal since it undergoes physiological degradation. The present study supports the development of tissue-engineered tracheal substitutes for airway disease.

Infrared thermal imaging associated with pain in laboratory animals.

The science of animal welfare has evolved over the years, and recent scientific advances have enhanced our comprehension of the neurological, physiological, and ethological mechanisms of diverse animal species. Currently, the study of the affective states (emotions) of nonhuman animals is attracting great scientific interest focused primarily on negative experiences such as pain, fear, and suffering, which animals experience in different stages of their lives or during scientific research. Studies underway today seek to establish methods of evaluation that can accurately measure pain and then develop effective treatments for it, because the techniques available up to now are not sufficiently precise. One innovative technology that has recently been incorporated into veterinary medicine for the specific purpose of studying pain in animals is called infrared thermography (IRT), a technique that works by detecting and measuring levels of thermal radiation at different points on the body's surface with high sensitivity. Changes in IRT images are associated mainly with blood perfusion, which is modulated by the mechanisms of vasodilatation and vasoconstriction. IRT is an efficient, noninvasive method for evaluating and controlling pain, two critical aspects of animal welfare in biomedical research. The aim of the present review is to compile and analyze studies of infrared thermographic changes associated with pain in laboratory research involving animals.

[Design of an electronic leech]. / Diseno de una sanguijuela electronica.

This research presents the development of a continual suction electromechanical device (CSED) which emulates the feeding characteristics of a medicinal leech to drain body fluids. After the research, design and building of the device, its performance in normal conditions with fluids of different viscosity was evaluated. Finally, the device was submitted to a test of blood draining in three adult male rabbits NZW with a weight of three kilograms, obtaining drain.

[Results of the experimental repair of osteochondral lesions in a pig model using tissue engineering]. / Resultados en la reparación experimental de lesiones osteocondrales en un modelo porcino mediante ingeniería de tejidos.

OBJECTIVE: To repair experimental osteochondral knee lesions in pigs using tissue engineering. MATERIAL AND METHODS: Eight 40-kg pigs underwent surgery. Cartilage and periosteal biopsies of their control knee were taken. Cartilage and periosteal cells were independently isolated, cultured and seeded in biodegradable PGA and PLA polymers that were fixed on the bottom of an osteochondral defect in the pig's experimental knee, with bioabsorbable Mitek implants. Four months later the pigs were sacrificed and the knees were analyzed with nuclear magnetic resonance imaging (NMRI), macroscopic assessment, histology, electron microscopy (EM), scanning electron microscopy (SEM) and SEM element analysis. RESULTS: All the defects were filled with cartilage-like tissue according to the NMRI evaluation and the visual examination. Hyaline-like cartilage was obtained in 3 defects and fibrocartilage in 5. The EM showed chondrocytes in the repair tissue. The SEM showed appropriate integration to the bone and the surrounding tissue. SEM element analysis showed sulphurized matrix attached to the bone with calcium and phosphates as predominant elements. DISCUSSION: Tissue engineering enabled the production of tissues similar to normal ones. The polymer fixation system was effective.

Reducción del tiempo de cicatrización por medio de laser de helio-neón. Modelo experimental en conejos / Reduction in wound healing by treatening wounds by helius-neon laser. An experimental model in rabbits

El objetivo del trabajo fue determinar las condiciones óptimas para una aceleración de la cicatrización en piel de conejos mediante el tratamiento de la herida con laser de helio-neón HeNe (632.8 nm). Para este fin se usaron dos grupos de 5 conejos cada uno, en uno se aplicó el tratamiento con laser y el otro sirvió de control. A los animales se les realizó un resección de piel de 2 x 5 cm. El grupo experimental se irradió con laser helio-neón con una potencia de 0.1 mW a una distancia aproximada de 3 cm, con un barrido en toda la herida, por un lapso de 5 min/día. Se tomó biopsia después de las 24 horas al primer conejo, posteriormente, cada 24 horas se tomó un conejo distinto y se realizó el análisis histológico. En el grupo experimental se observó un aumento en la actividad de los procesos de reparación, en comparación con el grupo control, como fue la proliferación de fibroblastos y el incremento en la fibras de colágena que sellaron la herida a partir del cuarto día. En las condiciones antes mencionadas se redujo el tiempo de cicatrización, por lo menos en un 40 por ciento comparado con el grupo control