Surgical and physiological challenges in the development of left and right heart failure in rat models.

Rodent surgical animal models of heart failure (HF) are critically important for understanding the proof of principle of the cellular alterations underlying the development of the disease as well as evaluating therapeutics. Robust, reproducible rodent models are a prerequisite to the development of pharmacological and molecular strategies for the treatment of HF in patients. Due to the absence of standardized guidelines regarding surgical technique and clear criteria for HF progression in rats, objectivity is compromised. Scientific publications in rats rarely fully disclose the actual surgical details, and technical and physiological challenges. This lack of reporting is one of the main reasons that the outcomes specified in similar studies are highly variable and associated with unnecessary loss of animals, compromising scientific assessment. This review details rat circulatory and coronary arteries anatomy, the surgical details of rat models that recreate the HF phenotype of myocardial infarction, ischemia/reperfusion, left and right ventricular pressure, and volume overload states, and summarizes the technical and physiological challenges of creating HF. The purpose of this article is to help investigators understand the underlying issues of current HF models in order to reduce variable results and ensure successful, reproducible models of HF.

Electro-acupuncture-induced neuroprotection is associated with activation of the IGF-1/PI3K/Akt pathway following adjacent dorsal root ganglionectomies in rats.

The aim of the present study was to investigate the putative role and underlying mechanisms of insulin­like growth factor 1 (IGF­1) in mediating neuroplasticity in rats subjected to partial dorsal root ganglionectomies following electro­acupuncture (EA) treatment. The rats underwent bilateral removal of the L1­L4 and L6 dorsal root ganglia (DRG), sparing the L5 DRG, and were subsequently subjected to 28 days of EA treatment at two paired acupoints, zusanli (ST 36)­xuanzhong (GB 39) and futu (ST 32)­sanyinjiao (SP 6), as the EA Model group. Rats that received partial dorsal root ganglionectomies without EA treatment served as a control (Model group). Subsequently, herpes simplex virus (HSV)­IGF­1, HSV­small interfering (si) RNA­IGF­1 and the associated control vectors were injected into the L5 DRG of rats in the EA Model group. HSV­IGF­1 transfection enhanced EA­induced neuroplasticity, which manifested as partial recovery in locomotor function, remission hyperpathia, growth of DRG­derived spared fibers, increased expression of phosphorylated (p­) phosphatidylinositol 3­kinase (PI3K) and Akt, and increased pPI3K/PI3K and pAkt/Akt expression ratios. By contrast, HSV­siRNA­IGF­1 treatment attenuated these effects induced by HSV­IGF­1 transfection. The results additionally demonstrated that HSV­IGF­1 transfection augmented the outgrowth of neurites in cultured DRG neurons, and interference of the expression of IGF­1 retarded neurite outgrowth. Co­treatment with a PI3K inhibitor or Akt siRNA inhibited the aforementioned effects induced by the overexpression of IGF­1. In conclusion, the results of the present study demonstrated the crucial roles of IGF­1 in EA­induced neuroplasticity following adjacent dorsal root ganglionectomies in rats via the PI3K/Akt signaling pathway.

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.

Emprego de Túnica albugínea heteróloga ovina como reforço de parede abdominal em ratos / Employment of ovine heterologous Tunic albuginea as abdominal wall reinforcement in rats

Hérnias são umas das afecções que mais acometem os pequenos e grandes animais, podendo ter origem traumática ou não. Estas afecções, geralmente, necessitam de um reparo cirúrgico o mais rápido possível, devido ao fato de suas consequências poderem levar o animal ao óbito. Alguns estudos têm avaliado o comportamento da túnica albugínea como biomaterial de enxertia para reforço de parede abdominal, obtendo resultados favoráveis. O presente trabalho tem como objetivo avaliar o comportamento do enxerto de túnica albugínea ovina na parede abdominal de ratos. Foram selecionados 30 ratos da raça Wistar, os quais foram divididos em 2 grupos de 15 animais, sendo um grupo controle (C), um grupo teste (TA), onde os animais receberam reforço de parede abdominal com túnica albugínea ovina. Cada grupo foi dividido em três subgrupos contendo cinco animais, que foram submetidos à eutanásia nos dias 7, 21 e 42. O material coletado foi submetido a análises macroscópicas e histopatológicas a fim de afirmar a aplicabilidade do material e propor a utilização da túnica albugínea heteróloga como material de enxertia para a reconstrução da parede abdominal. Nos animais do grupo TA observou-se maior infiltrado inflamatório, neovascularização, deposição de colágeno e fibrose do que nos animais do grupo controle, concluindo assim que a túnica albugínea ovina é um biomaterial que funciona como substrato e promove uma precocidade da cicatrização de parede abdominal de ratos.

Hernias are one of the infections that most affect small and large animals, and may have traumatic origin or not. These conditions usually require a surgical repair as soon as possible, due to the fact that its consequences can lead the animal to death. Some studies have evaluated the behavior of the Tunica albuginea as a biomaterial for grafting abdominal wall reinforcement, obtaining favorable results. This study aims to evaluate the ovine Tunica albuginea graft behavior in the abdominal wall of rats. We selected 30 Wistar rats, which were divided into 2 groups of 15 rats, with a control group (C) and a test group (TA) where the rats received abdominal wall reinforcement with ovine Tunica albuginea. Each group was divided into three subgroups with five rats that were sacrificed on days 7, 21 and 42. The collected material was submitted to macroscopic and histopathological analysis to affirm the suitability of the material and propose the use of heterologous Tunica albuginea as grafting material for the reconstruction of the abdominal wall. In the TA group there was a higher inflammatory infiltration, neovascularization and collagen deposition and fibrosis than in group control, thus concluding that the ovine Tunica albuginea is a biomaterial that acts as substrate and promotes precocity of the abdominal wall healing of rats.

Surgery and electrochemotherapy treatment of incompletely excised mammary carcinoma in two male pet rats (Rattus norvegicus).

Two male rats (Rattus norvegicus; 18 and 24 months old), were referred for treatment of large masses located in the axillary area. Following total body radiography and hematological and serum biochemical analysis, the rats were anesthetized, and the masses were surgically removed. Both lesions were diagnosed as mammary carcinoma based on histopathological diagnosis. The tumor beds were treated with two sessions of electrochemotherapy (ECT), two weeks apart. ECT involved cisplatin administration in the tumor bed, followed by a series of eight biphasic electric pulses. The treatment was well tolerated, and the rats were disease-free after 10 and 14 months. Therefore, adjuvant ECT resulted in good local control of mammary carcinoma and can potentially be used for adjuvant treatment of pet rats with cutaneous and adnexal tumors.

Surgical Skills Training with Cryopreserved Rat Stomachs.

The objective of this study is to present a high-fidelity bench model of cryopreserved stomachs that can be used while learning surgical skills. Thirty stomachs were harvested from Wistar rats at the end of non-abdominal research studies. The stomachs were washed with cold saline solution and filled with hyaluronic acid solution. The organs were then placed into cryovials and cryopreserved at -30 °C for 60 days. The stomachs were thawed to room temperature on the day of the surgical skills practice and two full-thickness incisions were made. Reporting on their experiences, 22 participants (73.33%) felt that the cryopreserved stomach was identical to in vivo rat stomachs, 24 (80.00%) reported that the stomach was easy to handle, and 27 (90%) reported the tissue was non-friable. Moreover, 29 participants (96.6%) finished the suturing without tears and 100% recommended it as a biomaterial for surgical training. The cryopreserved stomach is a practical, reproducible, low-cost, and high-fidelity bench model that allows surgical fellows to learn how to handle a stomach and improve their surgical abilities before performing surgery on patients or laboratory animals.

Technical Aspects and Benefits of Experimental Mouse Lung Transplantation. / Aspectos técnicos y utilidades del trasplante pulmonar experimental murino.

In recent years, the number of lung transplantations performed as the last option for many respiratory diseases has grown considerably, both in adults and children. However, the causes for the relatively short survival of lungs compared to other organ transplants still need to be studied. Techniques have improved since the 1950s when experimental lung transplantation began, and the different animal species used now include rodents. The advantage of using these small species is that the surgical model has been expanded and standardized, and different respiratory problems can be studied. In this review we examine the different technical strategies used in experimental transplantation in rats and mice, focusing on surgical techniques and anesthesia and monitoring methods, and highlighting the major contributions of mouse lung transplantation to the field.

Experimental Control for the Ovariectomized Rat Model: Use of Sham Versus Nonmanipulated Animal.

One of 2 models required by the U.S. Food and Drug Administration for registration of a treatment for osteoporosis, the ovariectomized (OVX) rat model, is widely used in scientific studies investigating sex hormone-deficient bone loss. The use of control nonhuman animals is critical because bone turnover may be affected by animal stress, use of anesthetic, and the mechanisms involved in wound healing. Historically, researchers have used sham-operated animals who undergo the same manipulations as the OVX rats, but ethical concerns require consideration of unmanipulated (unoperated) control animals to minimize animal distress and unnecessary procedures. Herein, we report the results of 3 studies including OVX, sham, and unmanipulated rats and the effects on bone mineral density and content (BMD/BMC) during 2 to 6 months postsurgery. Our data indicate that while OVX animals generally had lower BMD and BMC than animals in either of the control groups, no differences were observed between sham and unmanipulated animals at any of the time points assessed. However, because bone turnover is a long-term process, studies with longer duration and multiple endpoints are warranted to confirm these results.

Improving Research Practice in Rat Orthotopic and Partial Orthotopic Liver Transplantation: A Review, Recommendation, and Publication Guide.

BACKGROUND: Due to a worldwide shortage of donor organs for liver transplantation, alternative approaches, such as split and living donor liver transplantations, were introduced to increase the donor pool and reduce mortality on liver transplant waiting lists. Numerous details concerning the mechanisms and pathophysiology of liver regeneration, small-for-size syndrome, rejection, and tolerance in partial liver transplantation facilitated the development of various animal models. The high number of preclinical animal studies contributed enormously to our understanding of many clinical aspects of living donor and partial liver transplantations. SUMMARY: Microsurgical rat models of partial orthotopic liver transplantation are well established and widely used. Nevertheless, several issues regarding this procedure are controversial, not clarified, or not yet properly standardized (graft rearterialization, size reduction techniques, etc.). The major aim of this literature review is to give the reader a current overview of rat orthotopic liver transplantation models with a special focus on partial liver transplantation. The aspects of model evolution, microsurgical training, and different technical problems are analyzed and discussed in detail. Our further aim in this paper is to elaborate a detailed publication guide in order to improve the quality of reporting in the field of rat liver transplantation according to the ARRIVE guidelines and the 3R principle. Key Messages: Partial orthotopic liver transplantation in rats is an indispensable, reliable, and cost-efficient model for transplantation research. A certain consensus on different technical issues and a significant improvement in scientific reporting are essential to improve transparency and comparability in this field as well as to foster refinement.

A comparison of two common bile duct ligation methods to establish hepatopulmonary syndrome animal models.

The major drawback of the current common bile duct ligation (CBDL)-induced hepatopulmonary syndrome (HPS) animal model is the extremely high mortality rate that hinders experimental studies. The purpose of this study was to investigate an improved method of CBDL with the goal of developing a simple and reproducible rat HPS model after a single CBDL treatment. Two groups of male Sprague-Dawley rats underwent separate methods of CBDL: (1) the upper common bile duct ligation (UCBDL) group (n = 40), in which the first ligature was made near the junction of the hepatic ducts, and the second ligature was made above the entrance of the pancreatic duct; (2) the middle of the common bile duct ligation (MCBDL) group (n = 40), in which the first ligature was made in the middle of the common bile duct, and the second ligature was made above the entrance of the pancreatic duct. The CBDL-induced HPS rats were evaluated by pulse oximeter, arterial blood analysis, histopathology, and cerebral uptake of intravenous technetium-99m-labeled albumin macroaggregates (which reflects intrapulmonary vascular dilation). The mortality rates of the UCBDL group and the MCBDL group were 42.5% and 77.5%, respectively (P < 0.05). These results suggest that the UCBDL, a single improved procedure, provides a better method compared to the established HPS model, because of the relatively high success rate and the decreased risk of complications.

Reducing the number of animals used for microsurgery training programs by using a task-trainer simulator.

To master the skills needed for microsurgery techniques, residents must enrol in a long and complex training program that includes manipulations on simulators, on ex vivo tissues and finally in vivo training. This final step consists of performing vascular anastomoses on murine models. We propose here a simulation program designed to decrease the number of rats used during the final in vivo training. Our study presents the materials used, the various exercises proposed and their evaluations. Two identical student groups were compared in the framework of the University Diploma of Microsurgery. Group A (seven students) followed a classic training program, all of whom achieved permeable vascular anastomoses. A total of 149 rats were needed for this group. Group B (seven students) first validated their manipulations on the task-trainer simulation program. A mean of 6 h was necessary to obtain this validation. All these students achieved the required permeable vascular anastomoses but only 77 rats were used for this group. This simulation program spared 72 rats, abiding by the Russell and Burch concept of a humane experimental technique, namely the 3R principles. This home-made, cost-efficient and easy-to-use task trainer included various exercises with increasing difficulty levels and a progressive scoring system. We believe that microsurgery training needs to include both simple and sophisticated tools in order to reduce the number of animals used to master these surgical skills.

Evaluation of the sufficiency of pedicled temporoparietal fascial flap on rat head and neck defects: detailed anatomical study.

The temporoparietal flap containing the temporal fascia has a wide spectrum of applications in head and neck surgery. The aim of this study is to demonstrate a temporoparietal fascial flap model that can be used in various head and neck defects in rats. Ten male Sprague-Dawley rats weighing 250-300 g were used in this study. Temporoparietal fascial flaps were elevated with the axial pedicle from the rats using microsurgical techniques. The arc rotations of the flaps on the pedicles were examined and the dimensions of the defects these flaps could cover were identified. The flaps were observed to be the right size for use with defects of the occipital, temporal and mastoid regions, ear, facial nerve and the mandible. The temporoparietal fascial flap is an experimental flap model, which can be useful in experimental studies related to complex head and neck defects.

Optimizing the dosing interval of buprenorphine in a multimodal postoperative analgesic strategy in the rat: minimizing side-effects without affecting weight gain and food intake.

Buprenorphine is commonly used as (part of) postoperative analgesic treatment with dosage dependent side-effects such as pica behaviour. No strict consensus exists about the optimal dosing interval of buprenorphine, as its duration of action has been described as being in the range of 6-12 h. In this study, dosing intervals of 8 h (thrice-a-day) and 12 h (twice-a-day) for buprenorphine in a multimodal analgesic strategy (concurrent administration of a non-steroidal anti-inflammatory drug) were compared on food intake, weight and side-effects (gnawing on plastic Petri dishes and growth rate, indicative of pica behaviour) in rats. The food intake and weight of both intervals were comparable, as the animals from the twice-a-day group did not lose more weight or consumed less food during the analgesic period. The rats from the thrice-a-day group suffered from more side-effects, as the growth rate was decreased and more plastic was gnawed on. It is recommended to carefully evaluate analgesic and side-effects when using buprenorphine. When side-effects are observed, the possibility of increasing the dosing interval of buprenorphine should be explored. In this study, increasing the dosing interval of buprenorphine in a multimodal analgesic regimen resulted in reduced unwanted side-effects, without increasing weight loss or decreasing food intake. Although this is suggestive of provision of comparable analgesia, future studies including more pain-related readout parameters to assess the effect of the dosing interval on analgesic efficacy are recommended.

Assisted ventilation without endotracheal intubation in rats.

This technique was performed to allow for an additional approach to assist in ventilation. A modified ventilation nose cone was placed over the nose, which allowed the animal to not require endotracheal intubation. This method was effective in ventilating the animals during thoracic and abdominal procedures without requiring endotracheal intubation.