In the long history of mankind, animals have played significant roles.We owe much of our intellectual sophistication and societal status to animal husbandry. 1 Farming and agriculture have allowed humans to control their environment and an improved nutrition. The first rural settlements marked the birth of the ancient civilizations, 2 but also triggered the first zoonotic outbreaks and the beginning of public health concerns. 3 The earliest records of animal use coincide with the appearance of Hippocrates' concepts and the birth of Western medicine. 2 Jumping ahead 2400 years, in the year 2018 more than 20 000 animal subjects-exceeding 200 species-were part of translational studies worldwide, 4 in pre-clinical trials. 2 Animal modelling can provide reliable data to elucidate human diseases. 5 Despite benefiting our quality of life, animal research remains controversial. 3 There is a growing sense of disapproval over using household pets in experiments. 1 New technologies have been created to replace animals in research, but the position of ideal bone substitute remains open. 6 Thus, primary research on novel models continues paramount. 7 AbstractAnimal models are live subjects applied to translational research. They provide insights into human diseases and enhance biomedical knowledge. Livestock production has favored the pace of human social development over millennia. Today's society is more aware of animal welfare than past generations. The general public has marked objections to animal research and many species are falling into disuse. The search for an ideal methodology to replace animal use is on, but animal modeling still holds great importance to human health. Bone research, in particular, has unmet requirements that in vitro technologies cannot yet fully address. In that sense, standardizing novel models remains necessary and rabbits are gaining in popularity as potential bone models. Our aim here is to provide a broad overview of animal modeling and its ethical implications, followed by a narrower focus on bone research and the role rabbits are playing in the current scenario. K E Y W O R D Sanimal experimentation, bone density, Lagomorpha, translational medical research MACEDO Et Al.

Background: A primary splenic torsion occurs when the organ rotates around its vascular pedicle in the absence of any other concomitant disease. The occurrence of primary splenic torsion is rare, with a prevalence lower than 1%. Splenic torsion is more often related to dilated gastric volvulus syndrome, and it has no clear etiology despite reports that associate it with congenital abnormalities or traumatic ruptures of the gastrosplenic or splenocolic ligaments. This study reports a case of splenic torsion in an American Pit Bull terrier dog, its related symptomatology, and the treatment adopted.Case: A 3-year-old male American Pit Bull terrier dog weighing 32 kg was admitted to the hospital with symptoms of acute abdomen, lethargy, increased abdominal volume, discomfort, restlessness, and with a history of collapse three days prior to admission. Clinical examination revealed lethargy, pale mucous membranes, reduced capillary refill time, moderate dehydration, and hyperthermia. Abdominal palpation revealed increased abdominal volume in the epigastric and mesogastric areas. CBC and serum biochemistry profile revealed hypochromic normocytic anemia, leukocytosis with absolute neutrophilia and eosinopenia, mild hypoalbuminemia, and thrombocytopenia. PCR for detection of Babesia sp. and Ehrlichia sp., which returned negative results, and measurement of clotting time, which was prolonged, were performed to exclude immune-mediated hemolytic anemia. Radiographic and ultrasonographic images showed a normal stomach, but revealed presence of splenomegaly. An exploratory laparotomy allowed direct observation of the spleen, which exhibited an increased volume, a blackened, cold, hyperemic appearance, and a complete torsion of the splenic vascular pedicle; the surgical team opted to perform total splenectomy rather than undoing the pedicle twist. The animal returned to the hospital after 10 days exhibiting an excellent clinical condition. Healing of the incisional wound was satisfactory, with formation of epithelial tissue throughout its extension. Thirty days after the surgery, the hematological parameters were within normal ranges. The animal was discharged, and its owner received information on adequate nutrition.Discussion: Clinical evaluation of symptoms of discomfort and increase in abdominal volume, especially on the left side, together with the information of the anamnesis, led to a suspicion of splenic torsion in this case. Splenic torsion can exhibit numerous clinical signs; here, ultrasound imaging allowed diagnosis of this condition. The anemia observed by means of the hematological tests could be explained by sequestration of red blood cells by the rotated spleen, with and inflammatory leukogram resulting from inflammation of the poorly perfused parenchyma, local peritonitis, and, possibly, increased release of neutrophils from the bone marrow. Thrombocytopenia and prolonged clotting time may be secondary to splenic torsion, as shown in this case. Splenectomy is the treatment of choice in cases of acute splenic torsion. This procedure is relatively easy to perform. Additionally, merely undoing the torsion does not prevent its recurrence, and may allow necrotic debris to reach the circulation. No intercurrences or involvement of adjacent organs were observed in this patient. This is due to factors such as early diagnosis, preoperative stabilization of the patient, and the short time between diagnosis and the surgical procedure, reiterating its importance in emergency conditions such as splenic torsion.

Background: The common calcaneus tendon is formed by the common tendon of the femoral biceps muscle, tendon of the superficial digital flexor muscle and gastrocnemius muscle tendon, and its rupture is related to acute traumas in small animals. Among some applications described, surgical repair can be adopted in the correction of tendon ruptures and theuse of grafts may be indicated in some severe lesions, where it is not possible to perform tenorrhaphy. This study aims to report the case of a feline with rupture of the common calcaneus tendon in which the tenorrafia associated with the autogenous fascia lata graft was performed as adjuvant to the cicatrization of the same.Case: A 24-month-old, undefined male feline with approximately 3 kg was treated at the FCAV Veterinary Hospital, UNESP Jaboticabal, State of São Paulo, Brazil, with a history of falling, for approximately two weeks, and has since plantigrade posture. Upon physical examination, it was possible to identify a discontinuity of the common calcaneus tendon. The radiographs were performed, which did not show any bone changes. A hemogram and biochemical profile were performed, which were within normal limits. The patient underwent surgery, and a complete lesion of the common calcaneus tendon was identified, with a chronic aspect. Approximation of the stumps was impossible, so a flap of fascia lata, about two centimeters long and one centimeter wide, was removed, which was used as a bed and tendon support for tendon growth. After removal all of the present fibrosis, the tendon stumps were approximated by means of modified Kessler suture with mononylon thread, and fascia lata flap of the ipsilateral limb was sutured with separate single points in both tendon endsand in their lateral and medial portion. In the tibiotarsic joint, the external skeletal fixator type II was used for immobilization, during a period of 30 days. In the immediate postoperative period the patient was already able to support the member on the floor, with progressive improvement, and after 60 days of surgery the animal presented complete support of thelimb, without pain or any other alteration coming from the surgery. The animal presented a rapid recovery after surgical treatment with the autogenous fascia lata flap.Discussion: The rupture of the common calcaneus tendon is not commonly reported in felines and its occurrence is related to acute trauma, where the animals will present lameness and plantigrade posture. Depending on the degree of tendon involvement, there are different procedures that may be indicated, such as tenorrhaphy, reimplantation for avulsion cases, and transplantation with grafts when there is segment loss. In the present study, the use of tenorrhaphy associated with the implantation of autogenous lata-fascia graft was chosen, since the grafts generally provide the framework for healing due to its replacement by collagen tissue in the recipient, in addition to providing mechanical protection initially. Fascia lata, due to its antigenic character as being autogenous, has been shown to be a viable and easily obtained surgical option. The use of the fascia lata graft associated with external immobilization with external fixator type II in the tibiotarsal joint allowed an excellent result and is therefore a recommended treatment for cases of rupture of the common calcaneus tendon in felines.Keywords: cats, lameness, plantigrade stance.