Magnesium and riboflavin combination therapy following cortical contusion injury in the rat

Previous research has shown that magnesium chloride (MgCl₂) and riboflavin (B₂) both significantly improve functional recovery when administered shortly after frontal cortical contusion injury (CCI). The purpose of the present study was to examine the ability of combination treatments of MgCl₂ and B₂ to improve functional outcome following unilateral CCI. One hour post-injury, rats were administered MgCl₂ (1.0 mmol/kg), B₂ (7.5 mg/kg), MgCl₂ + B₂ (1 mmol/kg + 7.5 mg/kg), 1/2 MgCl₂ + 1/2 B₂ (0.5 mmol/kg and 3.75 mg/kg), or saline. Two days following CCI rats were tested on a battery of sensorimotor (vibrissae → forelimb placing and tactile removal test) and motor (staircase test). A regimen of MgCl₂ + B₂ significantly reduced the initial impairment and facilitated the rate of recovery on the tactile removal test and facilitated the rate of recovery on the forelimb placing test. The half-dose combination did not significantly improve functional recovery on the tactile removal test compared to the individual treatments; however, it did improve performance on the forelimb placing test compared to saline treatment. Administration of MgCl₂ improved performance on the placing and tactile removal tests on 2 post-operative days, as did treatment with B₂ on the tactile removal test. The results indicate that the full combination of MgCl₂ + B₂ significantly improved functional recovery to a greater extent than the individual treatments or the low dose combination group on forelimb placing but not on tactile removal. These findings suggest that administration of MgCl₂ + B₂ may provide better therapeutic action than individual treatments.