Inhibition of mononuclear phagocytes reduces ischemic injury in the spinal cord.

Transient ischemia to the lumbar and sacral sections of the spinal cord of rabbit leads to a deterioration in neurological function that usually worsens 24 to 48 hours after injury. This decline in movement of the hindlimbs develops simultaneously with the appearance of mononuclear phagocytes in the gray matter of injured neural tissue. Chloroquine and colchicine inhibit phagocytic and secretory functions in mononuclear phagocytes. When given up to 6 hours after an induced ischemic lesion in rabbit, this drug combination decreased the number of mononuclear phagocytes found within the gray matter of damaged spinal cord, improved the recovery of function of the hindlimbs and bladder, preserved spinal somatosensory evoked potentials, and promoted the survival of motor neurons. In contrast, the glucocorticoid dexamethasone, a weak inhibitor of mononuclear phagocytes in vivo, did not reduce the number of inflammatory cells in the spinal cord and did not improve motor and bladder functions. The suppression of mononuclear phagocytes soon after ischemic injury may offer a new approach in the treatment of vascular disease in the central nervous system.