Extended Data Fig. 1: Description of gastric EPO-GEMM procedure and analysis of body weight and inflammation post-electroporation.
From: Somatic mouse models of gastric cancer reveal genotype-specific features of metastatic disease
(A-I) Step-by-step illustration of the EPO-GEMM procedure: (a, b) After hair removal, scrubbing of the surgical site with povidone-iodine, and rinsing with 70% alcohol, incisions of the skin (A) and the peritoneum (B) of about 7 mm each are made in the epigastric region. (c) The stomach is localized in the peritoneal cavity and mobilized to the exterior using a curved forceps. The right forceps in the image holds the forestomach. (d) To open the stomach, a 4-mm incision is made in the forestomach. (e) The stomach is rinsed with prewarmed saline using a flexible oral gavage needle to remove any remaining food. (f) The epithelial part of the stomach is mobilized to the exterior through the incision in the forestomach using a curved forceps, and the plasmid mix is injected into the epithelial layer of the corpus region using a 30G needle. A small liquid filled bubble forms around the injection area (arrow). (g) The Nepagene tweezer electrodes are loosely placed around the plasmid-containing bubble and electric pulses are applied by the Nepagene electroporator. (h-i) The stomach is reversed, and the forestomach and all the layers are sutured at once in a continuous seam using absorbable sutures (Ethicon 5-0). Afterwards, the peritoneal cavity is closed by single knot sutures and the incision in the skin is closed by surgical staples. (j–l) Extent of inflammation after electroporation with vehicle only. (J) Edema with limited influx of neutrophils at the electroporation site seen 24 h after EPO, consistent with early signs of local inflammation. Representative image of n = 3 mice. (K) Influx of neutrophils in the mucosal area (dashed line) at the electroporation site seen 72 h after EPO, consistent with a developing inflammatory response. Representative image of n = 3 mice. (L) Acute inflammatory response characterized by influx of neutrophils in the glandular (g) and muscle (m) layers of the stomach at the electroporation site, seen 192 h after EPO. Representative image of n = 3 mice. (M) Changes in animal body weight over 8 days following the EPO procedure. Individual lines represent independent mice (n = 9 mice). (n–o) Levels of white blood cells (N) and neutrophils (O) in the peripheral blood of mice at the indicated time-points following electroporation with vehicle only. Untreated mice that were not subjected to surgery or EPO served as controls (n = 3 independent mice per group). Statistical analysis by unpaired two-sided t-tests. Data are presented as mean values +/− s.e.m.
