Single port laparoscopic long-term tube gastrostomy in Göttingen minipigs.

Oral dosing by gavage is often used to test compounds in minipigs. This method is also used for certain nutritional studies that require exact dosing. This procedure may be stressful for the animal and requires the assistance of more than one technician. We investigated whether a gastrostomy tube could be placed and maintained in Göttingen minipigs using a single port laparoscopic technique. As part of another study, laparoscopic gastrostomy tube placement was performed in 12 Göttingen minipigs (32 ± 2 kg) under general anesthesia. The procedure involved single port laparoscopic visualization of the stomach and placement of a locking pigtail catheter into the fundus region of the stomach. The minipigs were followed for three weeks after surgery and macroscopic and microscopic tissue reactions were evaluated at necropsy. All catheters were successfully placed and were easy to use. At necropsy it was evident that the catheter had entered the stomach in the fundus region in 11/12 of the animals. In one animal the catheter had entered the antrum region. None of the animals developed leakage or clinically detectable reactions to the gastrostomy tube. Histopathologically, only discrete changes were observed. Single port laparoscopic tube gastrostomy with a locking pigtail catheter is safe, simple and reliable and is an appropriate alternative to, for example, percutaneous endoscopic gastrostomy, when long-term enteral delivery of pharmacological or nutritional compounds is needed. The use of the gastrostomy tube was easy and, based on subjective assessment, feeding was minimally stressful to the animals.

Host response to porcine strains of Escherichia coli in a novel pyelonephritis model.

The initial pathology and pathogenesis of pyelonephritis and the influence of different strains of Escherichia coli were investigated in a novel porcine model. Nine female pigs were divided into three groups (A, B and C) and inoculated repeatedly into one renal pelvis with porcine pyelonephritis E. coli strain LK67 (P fimbriae PapG(I)), LK76 (type 1 fimbriae) or LK82 (type 1 fimbriae and P fimbriae PapG(II/III)), respectively. The contralateral kidneys were inoculated with saline and served as controls. Pigs were killed 6h post-inoculation (hpi). Differential leucocyte counts, serum biochemical analyses and measurement of serum concentrations of proinflammatory cytokines and acute phase proteins were carried out at 0, 3 and 6 hpi. Bacteriological evaluation of urine, kidneys, spleen, liver, abdominal swabs and blood samples and gross and histopathological evaluation of kidneys, renal lymph nodes, liver and spleen were performed by quantitative, semiquantitative and/or descriptive methods. Immunohistochemistry was used to identify cells expressing L1 antigen, CD3ɛ, CD4, CD8, CD79αcy and lysozyme, and to identify E. coli and Tamm-Horsfall protein (THP). E. coli was re-isolated from all inoculated kidneys. Gross and microscopical lesions of acute pyelonephritis were demonstrated in all but one kidney inoculated with E. coli, but in none of the control kidneys. Renal parenchymal infiltration with both neutrophils and mononuclear cells, primarily CD3+ T lymphocytes, was observed at 6 hpi. Most T lymphocytes were CD8+. Pigs in group C had the highest mean pathology scores. Neutrophils were the dominant renal leucocyte in this group, while the number of mononuclear cells was at least equal to the number of neutrophils in the lesions of pigs from groups A and B. Kidneys with a high number of E. coli had severe lesions. Systemic spread of E. coli was observed in five pigs. THP was observed interstitially in 89% of the E. coli-inoculated kidneys. In all groups, increased numbers of neutrophils and decreased numbers of lymphocytes and monocytes were shown by differential leucocyte count at 6 hpi, and from 3 to 6 hpi there was a significant increase in C-reactive protein concentration.

A novel method for transuterine identification of piglets.

Implantable microchips provide a secure, permanent and unique identification of individual animals. When performing fetal intervention studies in experimental animal models easy and secure identification of fetuses is desirable, as having test and control groups within the same uterus reduces the total number of animals used in a study. The aims of this study were: (1) to establish a protocol to identify porcine fetuses in utero by microchip implantation and (2) to assess postnatally whether clinical or pathological reactions to the implant occurred. Two Danish Landrace/Danish Large White crossbred sows at day 100 of gestation were used. The sows were sedated with azaperone and induced with propofol intravenously. Anaesthesia was maintained with isoflurane and oxygen. Antibiotics were administered intramuscularly (i.m.) at induction and analgesia was given pre-, intra- and postoperatively. A laparotomy was performed and the uterus exteriorized. The rump of the first fetus was recognized through the uterine wall and the thigh muscle of the fetus was fixed between the thumb and the forefinger. The microchip was then implanted into the fetus at an angle of 45 degrees i.m. in the lateral hindleg using an insertion device with a 12G needle. The same procedure was done in every fetus. The uterus was returned to the abdomen and the abdominal wall closed. The sows gave birth to 24 liveborn piglets and one stillborn. None of the liveborn piglets were limping at the time of birth and no visible cutaneous or palpable reactions on the hindlegs were observed. Following euthanasia, the microchip was easily localized and no macroscopic reactions at the implantation site were seen. None of the piglets had more than one microchip implanted. Histology showed a chronic mild foreign body granulomatous inflammatory response with peripheral eosinophils surrounding the microchip. No inflammation was evident in the adjacent muscles. It is concluded that transuterine identification of piglets two weeks before delivery is feasible using a microchip implant as an effective, easy and reliable method for identification of individuals after birth.

Cellular, hemostatic, and inflammatory parameters of the surgical stress response in pigs undergoing partial pericardectomy via open thoracotomy or thoracoscopy.

BACKGROUND: Thoracoscopy has been shown to reduce the inflammatory and immunologic response to surgical stress, as compared with corresponding open procedures in humans. The influence on the hemostatic system, however, has not been thoroughly evaluated. The current study aimed to compare the perioperative and immediate postoperative changes in cellular, hemostatic, and inflammatory parameters after a partial pericardectomy performed by either thoracoscopy or thoracotomy. METHODS: For this study, 16 pigs were randomly assigned to have a partial pericardectomy performed thoracoscopically or by thoracotomy. Blood was collected intraoperatively, then 10 min, 3 h, and 6 h after surgery. Whole ethylenediaminetetraacetic acid (EDTA)-stabilized blood and plasma were examined for cellular, hemostatic, and inflammatory parameters, respectively, and thromboelastography (TEG) was performed on citrated whole blood. RESULTS: No significant difference in any of the parameters measured was found between the two groups except for the TEG parameter R-time, which was significantly shorter in the thoracoscopic group 3 h postoperatively. In both groups, a significant postoperative state of hypercoagulability and increase in inflammatory parameters was found. Additionally, pig blood showed a high degree of hypercoagulability in preoperative measurements, as compared with other species. CONCLUSIONS: Partial pericardectomy performed by thoracotomy or thoracoscopy in pigs produces a surgical stress response of equal magnitude, as measured by cellular, hemostatic, and inflammatory changes.