The Expression of NE in Lung Tissues and Blood of the Severe Brain Injury and Gastric Juice Aspiration Rats
|School||Zunyi Medical College,|
|Keywords||neutrophil elastase acute lung injury severe brain injury aspiration|
Objective:To investigate expression and changes of neutrophil elastase (NE) in early stage of acute lung injury (ALI) induced by the severe brain injury and aspiration rats, and provide theoretical basis for study of pathogenesis and clinical prevention and cure about ALI of the severe brain injury and aspiration patients.Methods:①A modified Marmarou’s impact device was used to establish the rat models of severe brain injury.②80 rats of brain injury were randomly divided into group of severe brain injury (group SB, n=40) and group of severe brain injury complicating aspiration (group SA, n=40).The rats of group SA were produced models of brain injury and aspiration by intratracheal instillation of gastric juice (0.4ml/kg, pH=1.2) after brain injury.Group SB(including group SB1, SB2, SB4, SB6,10 for each group) and group SA (including group SA1, SA2, SA4, SA6,10 for each group) were sacrificed at 1h,2h,4h,6h after model established,then taken the required samples of tissues to observation and detection.Control group (Group C, n=10) was fed as usual without any injury treatment.③The levels of NE in BALF and plasma of rats were measured by ELISA, the expression of NE in lung tissues was determined by Real-time RT-PCR, the albumin concentration in BALF was detected by immune turbidimetry, the water content of the lung tissues of rats was calculated by measuring the wet and dry weight of lung tissues, the morphology changes of lung tissues of rats were observed by optical microscope and electron microscope.④Statistical analysis was performed by SPSS 13.0 statistics software.Results:①170 male SD rats (including control group) were used to produce models of severe brain injury,87 brain injury models have been successfully produced, the rest died in the production process, the mortality was 45.63%; 8 rats died in all in group SA when produced the aspiration models, and group SA1, SA2, SA4, SA6 survived 8,8,9,7 rats.②The rats became apneic immediately after brain injury, and the breath restored autonomously in a few seconds to a few minutes, then occurred shortness of breath, accompanied by full-body convulsions, cyanosis at oral lips and limbs, hemiplegia, meanwhile, some haematodes secretion in their mouths and nasal cavities. Physiological index, shuch as corneal reflex and body righting reflex et cetera, disappeared when the rats injured were comatose. The rats appearanced bucking, restlessness and dyspnea after gastric juice aspiration.③It could see hemorrhage and edema from appearance of brain tissues, and the histological changes of the brain tissues showed cavitas subarachnoidealis and cerebral hemorrhage, cerebral vessels hyperemia, tissue looseness, and nerve cell edema.④From the histological changes of the lung tissues, group C was without hyperemia, edema, hemorrhage and focal infarct form, group SB and SA presented various degrees of hyperemia, edema, local hemorrhage, and there were pink cystose fluid effused when extruding lung tissues; pathological section of group SB and SA showed micrangium of alveolar wall congestion, various degrees hydrops accumulation with hemorrhage in alveolar space, interstitial edema, alveolar septum widened, infiltration of PMN in interstitial tissue and airspaces. In electron microscope, group SB and SA showed type I pneumonocyte and mitochondria swelling, chromatin pyknosis even disappearance; nucleus of type II pneumonocyte disfiguration, mitochondria and lamellar body evacuation as vacuole, villi deformation and defluxio.⑤The levels of NE in BALF, plasma and lung tissues from group SB and SA were significantly higher than that from group C (P<0.01), and it increased gradually with prolongation of time. The NE concentration from group SA at different time were markedly higher than that from group SB (P<0.01).⑥The levels of albumin in BALF from group SB2～SB6 and SA1～SA6 were significantly more than that from group C (P<0.01), and it was on ascend trend with prolongation of time. The albumin concentration from group SB at different time were markedly lower than that from group SA (P<0.01).⑦Compared with group C, the wet/dry weight ratio of the lung tissue from group SB6, SA4 and SA6 increased significantly (P<0.01), it wasn’t statistically significant when the rest groups compared with group C (P>0.05). The W/D ratio of group SA6 was significantly higher than group SB6 (P<0.01), and it wasn’t statistically significant when the rests of group SA at different time compared with group SB (P>0.05).Conclusion:①NE plays an important role in the developmental process of acute lung injury rsulted from severe brain injury complicating gastric juice aspiration.②The acute lung injury rsulted from severe brain injury complicating gastric juice aspiration is more serious than that caused by severe head injury without gastric juice aspiration.③In the six hours after severe brain injury and aspiration,the degree of lung injury become more and more serious with time lengthening.④Inflammatory cells infiltrates within lung in the early phase after severe brain injury complicating gastric juice aspiration,which indicates it should enforce medicamentous intervention as early as possible to preventing or alleviating lung injury.