The goal of this experiment was to determine if the dose of the alfaxalone-based anesthetic combination identified above (AXB) would provide a depth of anesthesia sufficient for routine laparotomy. This study was performed using CFW mice (females, n = 5; males, n = 5).
Mice were anesthetized SC with 50AXB as described above. The times of injection, LORR, and loss of toe pinch reflex were recorded. Respiratory rate was monitored every 2 min until the surgical plane was achieved. Then respiratory rate, LORR, and loss of toe pinch reflex were monitored every 5 min until the end of the surgical procedure. Upon reaching a surgical plane of anesthesia, mice were moved over to a heating pad, and the eyes were lubricated with sterile artificial tear ointment. The abdomen was shaved and aseptically prepared with 3 alternating applications of iodine and isopropyl alcohol. A surgical drape (clear plastic, 8 in. × 8 in., Steris, Saxonburg, PA) was then placed over the mouse. The exploratory laparotomy included making a ventral midline abdominal incision through the skin with a scalpel blade (no. 15 Protected Disposable Scalpels, Bard-Parker, Danbury, CT) and extending the incision to 1.5 cm with a Metzenbaum scissor. Another incision was made into the linea alba to open the abdominal cavity, and the incision was extended to 1.5 cm with a Metzenbaum scissor. The abdominal contents were manipulated by moving the contents to the right and then to the left, exteriorizing the spleen and small intestines, and then returning them to the abdomen. The linea alba was closed with Monocryl 4-0 (Reverse Cutting, 19 mm, 3/8 c; Ethicon, Raritan, NJ) using a simple continuous pattern followed by closure of the skin layer with Autoclips (BD Autoclip, 9 mm; Thomas Scientific, Swedesboro, NJ). All mice received 0.05 mL of diluted 0.25% ropivacaine (0.5% ropivacaine HCl, Akorn, Lake Forest, IL) as a local analgesic after the abdominal wall was closed, before skin closure (Figure 1). Total surgery time was between 5 to 10 min. Time to recovery of toe pinch reflex, tail pinch reflex, and righting reflex were recorded. Mice were moved into a cage with soft bedding (Diamond Soft Bedding Teklad 7089, Envigo, Indianapolis, IN) after all 3 reflexes returned to baseline, and return of spontaneous movement was confirmed. To assist in recovery, 12 a diet gel cup (DietGel Recovery, Clear H2O, Westbrook, ME) and meloxicam tablets (Mouse MD's Meloxicam, 0.125-mg tablet, bacon flavor, Bio-Serv, San Diego, CA) were provided for 3 d. To allow the mice to become familiar with the meloxicam tablet, a placebo tablet (Rodent MD's Placebo, 5-g tablet, grain-based bacon flavor, Bio-Serv, San Diego, CA) was offered on the day before surgery.
Mice were monitored daily for 7 d after surgery, at which time the incision sites were fully healed. Mice were then euthanized with CO 2 per IACUC guidelines. A necropsy was performed due to unexpected death, but we did not perform a necropsy on all mice that were euthanized.
Mice were anesthetized SC with 50AXB as described above. The times of injection, LORR, and loss of toe pinch reflex were recorded. Respiratory rate was monitored every 2 min until the surgical plane was achieved. Then respiratory rate, LORR, and loss of toe pinch reflex were monitored every 5 min until the end of the surgical procedure. Upon reaching a surgical plane of anesthesia, mice were moved over to a heating pad, and the eyes were lubricated with sterile artificial tear ointment. The abdomen was shaved and aseptically prepared with 3 alternating applications of iodine and isopropyl alcohol. A surgical drape (clear plastic, 8 in. × 8 in., Steris, Saxonburg, PA) was then placed over the mouse. The exploratory laparotomy included making a ventral midline abdominal incision through the skin with a scalpel blade (no. 15 Protected Disposable Scalpels, Bard-Parker, Danbury, CT) and extending the incision to 1.5 cm with a Metzenbaum scissor. Another incision was made into the linea alba to open the abdominal cavity, and the incision was extended to 1.5 cm with a Metzenbaum scissor. The abdominal contents were manipulated by moving the contents to the right and then to the left, exteriorizing the spleen and small intestines, and then returning them to the abdomen. The linea alba was closed with Monocryl 4-0 (Reverse Cutting, 19 mm, 3/8 c; Ethicon, Raritan, NJ) using a simple continuous pattern followed by closure of the skin layer with Autoclips (BD Autoclip, 9 mm; Thomas Scientific, Swedesboro, NJ). All mice received 0.05 mL of diluted 0.25% ropivacaine (0.5% ropivacaine HCl, Akorn, Lake Forest, IL) as a local analgesic after the abdominal wall was closed, before skin closure (Figure 1). Total surgery time was between 5 to 10 min. Time to recovery of toe pinch reflex, tail pinch reflex, and righting reflex were recorded. Mice were moved into a cage with soft bedding (Diamond Soft Bedding Teklad 7089, Envigo, Indianapolis, IN) after all 3 reflexes returned to baseline, and return of spontaneous movement was confirmed. To assist in recovery, 12 a diet gel cup (DietGel Recovery, Clear H2O, Westbrook, ME) and meloxicam tablets (Mouse MD's Meloxicam, 0.125-mg tablet, bacon flavor, Bio-Serv, San Diego, CA) were provided for 3 d. To allow the mice to become familiar with the meloxicam tablet, a placebo tablet (Rodent MD's Placebo, 5-g tablet, grain-based bacon flavor, Bio-Serv, San Diego, CA) was offered on the day before surgery.
Mice were monitored daily for 7 d after surgery, at which time the incision sites were fully healed. Mice were then euthanized with CO 2 per IACUC guidelines. A necropsy was performed due to unexpected death, but we did not perform a necropsy on all mice that were euthanized.
