FIG. 6.

Persistent hyperglycemia post-TBI resulted in a decrease in cerebral edema, which was partially reversed by insulin administration. (A) Schematic diagram showing the paradigm for streptozotocin (STZ) administration, injury, and outcome analysis. (B) Administration of STZ 1 week prior to injury resulted in significant changes in tissue water content at 48 h post-injury, as measured by the hemisphere relative to the site of injury. The tissue water percentage was decreased in the STZ-treated animals (n = 8), relative to the vehicle group (n = 9), for all measures. (C) In a separate experiment in which a subset of STZ animals was treated with insulin post-TBI, animals responsive to insulin treatment (blood glucose [BG] level < 260 mg/dL; n = 6) displayed significantly greater edema in the contralateral hemisphere than untreated STZ animals (n = 7), or those that did not respond to insulin treatment (n = 6). The dotted line represents the average level of brain water content previously seen in uninjured animals (data are presented as mean ± standard error of the mean; *p < 0.05; TBI, traumatic brain injury).