Experimental design for pancreatectomy

All surgeries were performed under isoflurane anesthesia to alleviate pain, and all efforts were made to minimize suffering. Animals were monitored continuously after surgery until they were able to maintain sternal recumbency, as required by the Institutional Animal Care and Use Committee policy surgical guidelines. Subsequently, they were monitored twice daily for 3-5 d to ensure general health. The specific criteria used to monitor animal health included hunched posture, piloerection, abnormal feeding, drinking, and ambulation. If there were adverse signs that persisted for 24 h postoperatively or a pronounced sharp decrease in body weight (> 25%), the animals were euthanized using excessive anesthesia.

Animals were randomly sham-operated (Sham group, Sham, n = 6) or subjected to pancreatectomy (Px) (Experimental groups). The animals were divided into three groups: ventral pancreatectomy (VPx, n = 7), partial pancreatectomy (PPx, n = 8), and subtotal pancreatectomy (SPx, n = 6). For VPx, PPx, and SPx, different ranges of pancreatic resection were performed, as shown in Figure ​Figure1,1, corresponding to the resection of the right pancreas (VPx, Figure ​Figure1,1, area A, approximately 10% of the total pancreatic volume), the right pancreas and splenic lobe (area C, approximately 65%-75% of the total pancreatic volume) of the left pancreas (PPx, Figure ​Figure1,1, combined resection of areas A + C, approximately 75%-85% of the total pancreatic volume), right pancreas and gastric lobe (area B, approximately 5%-10% of the total pancreatic volume), and splenic lobes of the left pancreas (SPx, Figure ​Figure1,1, combined resection of areas A + B + C, approximately 85%-90% of the total pancreatic volume). The sham-operated animals were handled similarly, but their pancreas was not removed.

Diagram of the extent of pancreatic resection in Suncus murinus. Arrowheads indicate the splenic lobe of the left pancreas (area C). CBD: Common bile duct; CHA: Common hepatic artery; Du: Duodenum; Ga: Gastric lobe of the left pancreas (area B); GB: Gallbladder; RP: Right pancreas (area A); SMA: Superior mesenteric artery; Sp: Spleen.

Experimental data were collected for each animal (Figure ​(Figure2).2). Blood was collected through the submandibular vein 8, 10, 15, 17, 22, and 26 d after the operation, and body weight was measured on postoperative days 5, 11, 18, and 25. Intraperitoneal glucose tolerance test (IPGTT) and blood glucose testing were performed once and twice per week, respectively, after surgery. The average amount of food consumed for 7 consecutive days after surgery was taken as the first week’s food intake. The food intake for the second, third, and fourth weeks was calculated in sequence. Bromodeoxyuridine (BrdU) at a dose of 100 mg/kg body weight per day was injected intraperitoneally 3 d before sacrifice. All experimental animals were sacrificed 4 wk after surgery.

The schedule of experimental data collection. BC: Blood collection; BGT: Blood glucose testing; BrdU: Bromodeoxiuridin; BWM: Body weight measurement; IPGTT: Intraperitoneal glucose tolerance test.