Modeling both the mechanical and hypoxic features of traumatic brain injury in vitro in rats

In traumatic brain injury, the brain is subjected to mechanical shear and varying degrees of hypoxia/ischemia. To compare effects of stretch injury, hypoxia, and the combination of both insults on neurons, mixed neuronal and astrocytic cultures were established from day 17 fetal rat brains. On days 17-19 in vitro, cultures were subjected to stretch injury or hypoxia of varying degrees, alone and in combination. Cultures were assayed for lactate dehydrogenase release and Trypan Blue uptake. Hypoxia or Stretch injury alone induced a graded response (P<0.05) on both assays. Stretch+Hypoxia (4 or 6 h) resulted in significantly greater injury as compared with controls (P<0.05), and as compared with either isolated Stretch or Hypoxia (1, 2, 4 or 6 h) alone (P<0.05).