Behavior of Rats in the Open Field within the Early Period after Light-Degree Blast-Induced Neurotrauma

Blast-induced neurotrauma (BINT) is a specific type of traumatic brain injury (TBI). At present, this type of injury is rather widespread throughout the world due to its occurrence in military conflicts and terrorism acts. Consequences of such traumas form an important social and medical problem. Brain injuries in the case of BINT result mostly from a specific action of the main pathological factor of explosion, the shock wave. Experimental studies of BINT consequences have been concentrated on its different aspects and were carried out using variable techniques of modeling; thus, some links of the BINT pathogenesis have been insufficiently examined. In our study, we modeled BINT in rats using a self-made pneumatic device that produced a baroacoustic wave with the excess pressure of about 25 kPa and examined behavioral activity of the experimental animals subjected to the action of this factor in the open-field test within acute and early segments of the post-traumatic period. After initial increases in the intensities of horizontal and vertical motor activities (in the case of vertical activity, dramatic and more long-lasting), these behavioral phenomena were later on significantly suppressed. Exploration of openings in the arena floor (burrows) and the performance of grooming episodes were suppressed within the entire observation period. A part of grooming events was transformed into an abortive pattern. It should be concluded that high anxiety related to primary pathological effects of the shock wave were obvious within the acute period (days 1–7). Within the early post-traumatic period (days 7–21), the animals experienced fear and demonstrated signs of depression; this was probably related to secondary damage to the brain against the background of neuroinflammation and neuromediatory imbalance.