Establishment of animal models of primary brain explosive injury in dogs and their early treatment with mannitol

Objective To establish new experimental models of primary explosive injury to brain in dogs and investigate the effect of early treatment on primary explosive injury in dogs by using two doses of 20% mannitol. Methods Thirty-six mongrel male dogs were randomly divided into three groups: model group, high-dose treatment group and low-dose treatment group (n=12). Models of primary craniocerebral explosive injury were established in all the groups. Dogs in the high-dose treatment group and low-dose treatment group were given 1.0 g/kg and 0.5 g/kg 20% mannitol 6 h after injury, and these treatments were given every 6 h; 0, 3, 6, 12, 24 and 48 h after injury, respiratory frequency, heart rate, blood pressure (BP), intracranial pressure (ICP), CT of skull, urea nitrogen (BUN), creatinine (Cr) and survival time were observed and compared. Results The levels of respiratory frequency and heart rate were significantly increased, and the levels of BP and ICP were significantly decreased in the high-dose treatment group and low-dose treatment group as compared with those in the model group 12, 24 and 48 h after injury (P<0.05); 24 and 48 h after injury, as compared with those in the model group and high-dose treatment group, the levels of BUN and Cr in the low-dose treatment group were significantly lower (P<0.05). The midline shift in the high-dose treatment group ([3.5±0.41] mm) and low-dose treatment group ([3.3±0.22] mm) was significantly decreased than that in the model group ([6.4±0.50] mm) 48 h after injury (P<0.05). The survival time in both high-dose treatment group (131.6±8.73 h) and low-dose treatment group (133.7±9.31 h) was significantly longer than that in control group (96.0±3.0 h, P<0.05). Conclusion Early proper treatment for primary craniocerebral explosive injury by using mannitol can relieve the indexes of respiratory frequency, heart rate, BP and ICP, and relieve the severities of cerebral edema, prolong the survival time in dogs, but high-dose 20% mannitol might aggravate the kidney damage of the injured dogs. Key words: Explosive injury; Craniocerebral injury; Mannitol