EFFECTS OF CLOSED-HEAD TRAUMA AND LIPOPOLYSACCHARIDE ON BODY-TEMPERATURE, BRAIN-TISSUE WATER-CONTENT, AND PGE2 PRODUCTION IN RATS

Closed head trauma (CHT) increases brain tissue prostaglandin E2 (PGE2 ) concentration, and that increase is associated with cerebral edema f ormation and worsening of the neurologic severity score (NSS). Injecti on of the bacterial endotoxin lipopolysaccharide (LPS) increases cereb ral and hypothalamic PGE2, and the hypothalamic increase is associated with increased body temperature. The present study determined (a) whe ther LPS-induced increase of PGE2 causes brain edema or worsens NSS an d (b) whether CHT increases hypothalamic PGE2 and thereby increases bo dy temperature. Halothane-anesthetized rats were divided into four gro ups: group 1 = surgery with no CHT and no LPS (n = 8), group 2 = surge ry with LPS and no CHT (n = 8); group 3 = surgery with CHT and no LPS (n = 8); and group 4 = surgery with CHT plus LPS (n = 8). NSS was dete rmined at 1 and 24 h after injury, and brain tissue PGE2 and edema wer e determined when animals were killed 24 h after injury. As compared w ith group I,LPS alone, but not CHT or CRT plus LPS, increased rectal t emperature. CHT and CHT plus LPS, but not LPS alone increased brain wa ter content and worsened NSS. LPS, CHT, and CHT plus LPS all increased hypothalamic and cerebral PGE2 production. We conclude that although LPS and CHT increased PGE2 levels, LPS alone did not affect neurologic status or brain edema, CHT did not increase rectal temperature, and a ddition of LPS to CHT did not aggravate the sequelae of CHT.