Impact one stereotaxic impactor cci

Animals were anesthetized using isoflurane (1.3%) and Zoletil (20 mg/kg). Under aseptic conditions, the simulated surgery group exposed the dura mater of the T8–T9 segment, with a width of 0.5 cm. The spinal cord was exposed under the pia mater, and injury was inflicted using the Impact One Stereotaxic Impactor-CCI (Leica Microsystems, Durham, NC, USA) with an impact force of 1.5 m/s. The signs of a successful confirmation of the model are the appearance of unsteady swing and tail flick reflex in rats. Post-surgery, animals received daily gentamicin (5 mg/kg) for seven days and underwent manual bladder emptying until the return of the voiding reflex.

The experiments were performed on 75 9-week-old male C57BL/6 mice weighing 21–25 g, which were kept under 12:12 light and dark cycle with access to food and water ad libitum. Surgery was performed 1 week after recovery from transportation-related stress. Mice were anesthetized with isoflurane (3% induction, 2% maintained). The skull was fixed in a stereotactic frame and a 5-mm craniotomy was performed above the left parietal cortex. We performed mild–moderate controlled cortical impact (CCI) injury (coordinates: 2 mm lateral, 2 mm posterior to Bregma) at an impact depth of 1 mm, with a 2 mm diameter round impact tip (speed 3.6 m/s, dwell time 100 ms) and a 12° angle, using an electromagnetically driven CCI injury device (Impact One stereotaxic impactor CCI, Leica Microsystems Gmbh, Wetzlar, Germany). The bone flap was replaced but not sealed, the skin was sutured, and the mice were allowed to recover fully from anesthesia before transfer to their home cages. The mice were sacrificed at 5 h, 1, 3, 7, 14, 30, and 60 days after CCI injury. The control group for all comparisons was comprised of age-matched uninjured naïve mice (n = 4–5). All animal studies were approved by the USUHS Institutional Animal Care and Use Committee and were conducted in accordance with the NRC guide to the Care and Use of Laboratory Animals.

Mice were anesthetized with isoflurane (4% for induction, 2–3% for maintenance) and securely positioned in a mouse stereotaxic frame (Stoelting Co). Surgery was performed as described previously (Villapol et al., 2012 ; Yi et al., 2012 (link)). Briefly, an incision was made over the forehead, and the scalp was reflected to expose the skull. A craniotomy was made over the left hemisphere and the bone flap was carefully removed. Mice were injured over the left somatosensory cortex (0 bregma, 2 mm lateral to the suture line) at an impact depth of 1 mm with a 2-mm diameter round impact tip (speed 3.6 m/s, dwell time 100 ms) using an electromagnetically driven CCI injury device (Impact One™ stereotaxic impactor CCI, Leica Microsystems GMBH) (Brody et al., 2007 (link); Pleasant et al., 2011 (link)). These CCI parameters lead to an injury that is considered mild to moderate according to our experience and previous publications (Washington et al., 2012 (link); Yi et al., 2012 (link)). The dura remained intact following craniotomy. Impact caused occasional extradural hemorrhages with mild edema. Following injury, the bone flap was replaced but not secured, and the scalp was sutured closed. Mice were under isoflurane for no longer than 15 min. After recovery from anesthesia, mice were maintained in a warm recovery cage for 1 h and returned to home cages.