MASCIS Spinal Cord Contusion Model

The impactor is the most widely used rodent spinal cord injury model. The Multicenter Animal Spinal Cord Injury Study (MASCIS) adopted the model in 1993 and standardized protocols for anesthesia, surgery, spinal cord contusion, and post-injury care of rats, as well as specific outcome measures. The MASCIS model stipulates Long-Evan's hooded rats that are 77 ± 1-day old and anesthetized with pentobarbital (intraperitoneal 45 mg kg⁻¹ female, 6 mg kg⁻¹ male). After removing the T10 and half of T9 lamina, the rat is suspended by clamping the T8 and T11 dorsal vertebral processes. The Impactor is used to drop a 10-gram rod 12.5, 25.0, or 5.0 mm onto T11 spinal cord. The Impactor tracks the trajectory of the falling rod (±10 μm and ±10 μs) and measures impact velocity (Vi), cord compression distance (Cd), time (Ct), and rate (Cr = Cd/Ct). The rats get tracheal suction for respiratory depression and subcutaneous saline (5–10 ml) for dehydration. The rats are treated with cephalosporin (25 mg kg⁻¹ day⁻¹) for 7 days and daily bladder expression. Recurrent urinary tract infections are treated with a 10-day course of enrofloxacin (2.5 mg kg⁻¹ day⁻¹). If the rats develop autophagia, they receive daily oral acetaminophen (65 mg kg⁻¹ Children's Tylenol). Spinal cord lesion volume is estimated from Na and K concentrations of the spinal cord. Walking recovery is assessed with the BBB locomotor scale. Spared white matter is used to assess spinal cord damage at 6–12 weeks.