An optimization and refinement of the whole-gut transit assay in mice.

BACKGROUND: Gastrointestinal motility measurements in mice are currently performed under suboptimal conditions, as these nocturnal animals are measured during light conditions. In addition, other stressors, like individual housing, placement in a new cage during observation, and lack of bedding and cage enrichment cause animal discomfort and might contribute to higher variability. Here we aimed to develop a refined method of the widely-used whole-gut transit assay. METHODS: Wildtype mice (N = 24) were subjected to the standard or refined whole-gut transit assay, either with or without a standardized slowing in gastrointestinal motility induced by loperamide. The standard assay consisted of a gavage with carmine red, observation during the light period and individual housing in a new cage without cage enrichment. For the refined whole-gut transit assay, mice were gavaged with UV-fluorescent DETEX®, observed during the dark period, while pairwise housed in their home cage with cage enrichment. Time until excretion of the first colored fecal pellet was assessed, and pellets were collected to assess number, weight, and water content. KEY RESULTS: The DETEX®-containing pellets were UV-detectable, allowing to measure the mice in their active period in the dark. The refined method caused less variation (20.8% and 16.0%) compared to the standard method (29.0% and 21.7%). Fecal pellet number, weight, and water content was significantly different between the standard and refined method. CONCLUSIONS & INFERENCES: This refined whole-gut transit assay provides a reliable approach to measure whole-gut transit time in mice in a more physiological context, with reduced variability compared to the standard method.

An optimized medial parapatellar approach to the goat medial femoral condyle.

Goats or sheep are the preferred animal model for the preclinical evaluation of cartilage repair techniques due to the similarity of the goat stifle joint to the human knee. The medial femoral condyle of the stifle joint is the preferred site for the assessment of articular cartilage repair, as this is the primary location for this type of lesion in the human knee. Proper surgical exposure of the medial femoral condyle is paramount to obtain reproducible results without surgical error. When applying the standard human medial arthrotomy technique on the goat stifle joint, there are some key aspects to consider in order to prevent destabilization of the extensor apparatus and subsequent postoperative patellar dislocations with associated animal discomfort. This paper describes a modified surgical technique to approach the medial femoral condyle of the caprine stifle joint. The modified technique led to satisfactory exposure without postoperative incidence of patellar luxations and no long-term adverse effects on the joint.

Autologous transplantation of ischemically injured kidneys in pigs.

BACKGROUND: Expansion of the organ donor pool can be obtained through novel interventions attenuating ischemic acute kidney injury, which will enable the use of kidneys that suffered prolonged ischemia. In basic science, new therapeutic targets are identified that should be tested in a relevant large animal model before use in human kidney transplantation. MATERIALS AND METHODS: The current paper provides a detailed description of the technique of autologous transplantation of ischemically injured kidneys in pigs with special emphasis on perioperative care. RESULTS: The animal model was validated by showing that renal function after transplantation was proportional to the duration of warm ischemia before organ recovery. The extent of renal dysfunction was reproducible following kidney transplantations with the same warm ischemia time. CONCLUSIONS: Our experience may reduce the learning curves of other research groups taking an interest in the model and improve preclinical testing of novel interventions that modulate renal ischemia and reperfusion injury in kidney transplantation.

Increased EEG delta frequency corresponds to chorioamnionitis-related brain injury.

We evaluated the impact of chorioamnionitis on the intrapartal EEG delta frequency in the non-anesthetized preterm sheep. 10 mg intra-amniotic LPS or saline were given 2 or 14 days before preterm birth at gestational day 125. Lambs were delivered by Caesarean section under local anesthesia. A 5-minute EEG depicted delta activity and amplitude, and the relationship between EEG delta activity and both the white matter (WM) and cortical microglial activation and apoptosis was analyzed. EEG delta activity was increased significantly in the 14-day LPS preterm fetuses compared to both preterm control and 2-day LPS animals (p less than 0.05). No differences were seen between controls and the 2-day LPS fetuses. A direct association was demonstrated between EEG delta activity and both cortical microglial activation (r = 0,645, p = 0,024) and apoptosis (r = 0,580, p = 0,048), and between delta and WM activated microglia (r = 0,742, p = 0,006) and apoptosis (r = 0,777, p = 0,003). This study is the first to show a relationship between brain dysfunction and chorioamnionitis-related injury at birth.