Microvascular Permeability Damage And Mechanism Of Endothelial Injury Induced By Blast Wave

Objective:1. To establish a stable and reliable animal model of blast injury, which could be used tounderstand the propagation law of blast wave in different tissues.2. To investigate the dose-effect relationship between blast wave and microvascularpermeability.3. To explore the mechanism of microvascular endothelial damage after blast.4. To seek prognostic markers for multi-organs dysfunction after micro-vascularpermeability damaged by blast wave.Methods:1. Paper detonators were exploded at different distances in front of the conjuncture ofchest and abdomen of the animal, and meanwhile the pressure data in the air and in differentorgans were detected. The data were analyzed and fitted through mathematic model. Thetransmission rules of blast wave in the air, subcutaneous tissue, liver, chest and blood vesselwere summarized.2. We observed the albumin leakage rate, the ratio of residual radioactivity with125I-albumin-label method, and also observed the changes of the whole blood hematocrit afterthe animals were injured by different intensity of blast wave.3. After the animals were injured by different-intensity of blast wave, histologicalsections of lungs, kidneys, liver and intestines were observed under light and electronmicroscope.4. The blood level of creatine phosphokinase (CPK), lactate dehydrogenase(LDH),c-reactive protein(CRP), tumor necrosis factor(TNF-α), interleukin (IL-8and IL-10)andglucose were detected before and1hr after the animals were injured by detonations atdifferent distances. Results:1. The animal model of blast injury generated by paper detonators (RDX0.9g, DDNP0.4g)exploded at the distances of10cm,15cm,20cm and30cm from conjuncture of chest andabdomen was stable and reliable. The propagation laws of blast wave were different in skin,blood vessels, chest and liver. In the arterial system, the attenuation of shock wave is slow; itmay cause hemodynamic changes ultimately resulting in the damage of small blood vessels.2Albumin leakage rate was statistically different between the10cm distance injuriedgroup and control group (p <0.05). Residue of the125I-albumin in the organs increasedsignificantly in10cm distance injuried group especially in kidneys and lungs. Residualradioactivity in kidneys(p<0.05)or lungs(p<0.01)was statistically different between injuredgroups and control group. Hematocrit had statistically different increases in10cm(p<0.01),15cm(p<0.05)and20cm(p<0.05)distance injuried group between before and after thedetonations.3Pulmonary microvascular endothelial cells showed significant edema and a largenumber of intracytoplasmic vacuolization formation after blast injury. Higer intensity ofshock wave can disrupt the continuity of pulmonary microvascular endothelial cells, andwould widen the endothelial cell gap. In kidney, glomeruli and proximal tubule endothelialcell swelling were observed41hr after injury, CPK level in serum was statistically different between every injuriedgroup and control group (p <0.01), LDH level in serum was statistically different between the10cm distance injuried group and the control group(p <0.01), glucose level in serum wasstatistically different between10cm or15cm distance injuried group and control group(p<0.01); IL-8and IL-10level in serum were statistically different between10cm,15cm or20cm distance injuried group and control group(p <0.01). There were no statistical differencein CRP and TNF-α level in serum..Conclusion:With paper detonators (RDX0.9g, DDNP0.4g)exploded in10cm,15cm,20cm and30cm distance, we can establish a stable and reliable animal model of chest and abdomenblast injury. Different intensity of blast wave could bring about varying degree of increase inmicrovascular permeability, which can resulting in blood plasma albumin occult loss and blood concentration, and ultimately trigger the dysfunction of microcirculation. Endothelialcell injury may be an important mechanism for multi-organs dysfunction after blast injury.CPK, LDH, IL-8and IL-10levels in serum could be prognostic markers for multi-organsdysfunction after blast injury.