METABOLIC QUANTIFICATION OF LESION VOLUME FOLLOWING EXPERIMENTAL TRAUMATIC BRAIN INJURY IN THE RAT

A reliable and rapid method for quantifying lesion volume following tr aumatic brain injury (TBI) has vast potential in brain injury research . Staining with 2,3,5-triphenyltetrazolium chloride (TTC) provides for demarcation of damaged or infarcted tissue from normal, viable cerebr al tissue, in which a red formazan product is formed by reduction duri ng cellular respiration of mitochondrial dehydrogenase enzymes. The pr esent study evaluated the use of TTC staining to quantify the cortical lesion volume in rats undergoing fluid-percussion (FP) brain injury. Male Sprague-Dawley rats (350-450 g, n = 27) were anesthetized (sodium pentobarbital, 60 mg/kg, ip) and subjected to lateral FP brain injury of mild (1.1-1.3 atm, n = 5), moderate (2.0-2.3 atm, n = 9), or high (2.4-2.6 atm, n = 8) severity, while sham (noninjured) animals (n = 5) were anesthetized and surgically prepared without injury. Forty-eight hours after injury animals were sacrificed, brains were stained with TTC, and lesion volumes were calculated. A highly significant correlat ion was found between cerebral cortical lesion volume (mm(3)) and seve rity of brain injury (r = 0.85; p < 0.0001). The mean (+/- SD) lesion volumes were 12.1 (+/- 4.5) mm(3) following mild injury, 33.8 (+/- 8.6 ) mm(3) following moderate injury, and 45.1 (+/- 14.0) mm(3) following severe injury. A significant difference was observed between all inju ry groups using a t test with Bonferroni correction (p < 0.05). These results suggest that the TTC staining technique is a useful, rapid, an d reproducible method for quantification of lesion volume following la teral FP brain injury.