Tracheal bifurcation located at proximal third of oesophageal length in Sprague Dawley rats of all ages

Levrat’s rat model is often the first choice for basic studies of oesophageal adenocarcinoma. The position of the tracheal bifurcation represents the preferred location for the high-intrathoracic anastomosis following oesophagectomy for cancer and is thus of importance in basic research of oesophageal adenocarcinoma. In addition, it is also the typical location for trachea-oesophageal fistulae in congenital oesophageal atresia and its rat model. We thus analysed whether the position of the tracheal bifurcation would be affected by a rat’s growth throughout life. We analysed absolute and relative carinal position of the tracheal bifurcation and its relationship to oesophageal length in two cohorts of Sprague Dawley rats (RjHan:SD) of both sexes: one consisted of 30 eight-week old rats and the other of 20 rats aged between 15 and 444 days. We analysed their relationship by Pearson’s r and univariate linear regression. Bootstrap confidence intervals were calculated for all calculated coefficients. Absolute carinal position correlated with oesophageal length in the eight-week old cohort (r=0.4, 95% CI: 0.08-0.71, p=0.015) and those of different ages (r=0.92, 95% CI: 0.77-0.96, p=0.0066). Absolute carinal position increased with oesophageal length in both cohorts (F(1,28)=5.56; p=0.0256 and F(1,18)=94.93; p<0.0001 respectively). Consequently, relative tracheal bifurcation position was not influenced by oesophageal length in both cohorts (F(1,28)=2.49; p=0.1257 and F(1,18)=1.92; p=0.183). Absolute carinal position increased with oesophageal length, but relative position remained constant at around 30% of proximal oesophageal length throughout life

Clicker Training Mice for Improved Compliance in the Catwalk Test

The CatWalk test relies on the run of mice across the platform to measure a constant speed with low variation. Mice usually require a stimulus to walk to the end of the catwalk. However, such stimuli are usually aversive and can impair welfare. Positive reinforcement training of laboratory animals is a thriving tool for refinement and contributes to meeting the demands instituted by Directive 2010/63/EU. We have already demonstrated the positive effects of clicker training. In this study, we trained male and female mice to complete the CatWalk protocol while assessing the effects of training on their well-being (Open Filed and Elevated Plus Maze). In the CatWalk test, we observed that clicker training improved the running speed of the mice. In addition, clicker training reduced the number of runs required by mice, which was more pronounced in males. Clicker training lowered anxiety-like behaviors in our mice, especially in females, where a significant difference was observed between trained and untrained ones. Based on our findings, we hypothesize that clicker training is an effective tool to motivate mice and increase performance on the CatWalk test without potentially impairing their welfare (e.g., by puffing them)

Evaluation of the IUE simulator.

(A-E) The user responses to each of our questions to evaluate the IUE simulator. The X-axis indicates percentage points, while the Y-axis indicates the level of user experience. Statistical comparisons were made according to the ’ ’user’s level of expertise (Expert in white and beginner/intermediate in black). Student’s t-test was used for statistical comparison (n = 3). Significance was set as P-value less than 0.05. Bars in the graph represent SD. (F) indicates the statistical comparison between the questions. The X axes indicate percentage points, whereas the Y axis indicates the respective question. The one-way ANOVA followed by Tukey’s HSD (honestly significant difference) test was used for statistical comparison. Significance was set as P-value less than 0.05. Different letters indicate significant differences. Data are depicted in percentage units.</p

Steps of mold creation from the digital embryo model.

(A) Importation of embryo model into Netfabb. (B) Importation of the posterior ventricle into Netfabb. (C) Creation of a box from the part library; it was scaled to cover the embryo model. (D) The plane cut through the box, the embryo model, and the lateral ventricle model. (E) Merging of the upper and lower parts of the lateral ventricle after the plane cut. (F) Subtraction of the head part of the embryo after the plane was cut from the surrounding box with the "Boolean difference" function. (G) Subtraction of the embryo body model after the plane is cut from w the surrounding box with the "Boolean difference" function. (H) Separation of the embryo’s body mold into two halves to create the final silicon embryo.</p

Simulation of <i>in utero</i> electroporation (IUE).

(A) Opening of the mouse abdominal cavity. (B) Handling of embryos outside of the abdominal cavity. (C) Injection of the DNA-containing solution in the lateral ventricle. (D) Application of voltage through forceps-type platinum electrodes.</p

Questionnaire for the <i>in utero</i> electroporation simulation model.

Questionnaire for the in utero electroporation simulation model.</p