Changes And Mechanisms Of Immunodepression After Ischemic Stroke

ObjectiveTo investigate the changes and mechanisms of immune functionafter ischemic stroke by the changes of patients and mice C57BL/6’s lung, spleen and peripheral blood after ischemic stroke, to provide new ideas and methods for the treatment of ischemic strokeand the prevention and treatmentof infections after ischemic stroke.MethodsClinical data of 30 patients with ischemic stroke (stroke group),30 patients with brain tumor(brain tumor group) and30healthy controls(control group) were collected continuouslyin the First Affiliated Hospital of Kunming Medical University from October 2013 toJanuary 2014,toanalysis the infection rate of pneumonia and thecellcounts of blood leukocyte subsets of the three groups.Forty-eight mice C57BL/6 were randomly assigned to stroke group(n=32) and control group(n=16). The acute ischemic stroke model was established in experiment group by Middle Cerebral Artery Occlusion(MCAO) and no stroke was performed in control group. Divide the stroke group into MCAO 24h group,MCAO 48h group and MCAO72h group according to their survival time.Takeout the brain, spleen and lung on 24 hours, 48 hours and 72 hours after modeling.Observe the cerebral infarction bystaining the brain with TTC and the lung inflammation by staining the lung with HE.Measure the spleen weight, spleen weight index and spleen cell counts ofeach group and analyze the apoptosis situation of spleen cells by flow cytometry.Results1. The pneumonia infection rate of the stroke patients is higher than the brain tumor patients and the healthy controls.The infection rate of pneumoniain each group:the stroke group is 36.7%, the brain tumor group is 3.3% and the control group is 0, between the stroke group and the brain tumor group differences were statistically significant, between the stroke group and the control group differences were statistically significant.2. Theperipheral blood lymphocyte count in each group:the stroke group is(1.59±0.73)×109/L, the brain tumor group is(1.98±0.79)×109/L and the control group is(2.21±0.51)×109/L.Theperipheral blood leukocyte count in each group:the stroke group is(8.37±3.15)×109/L, the brain tumor group is(6.96±2.14)×109/L and the control group is(6.68±1.49)×109/L.Theperipheral blood neutrophil count in each group:the stroke group is(6.16±3.34)×109/L, the brain tumor group is(4.40±2.11)× 109/L and the control group is(3.91±1.18)×109/L. Theperipheral blood monocyte count in each group:the stroke group is(0.51±0.19)×109/L, the brain tumor group is(0.40±0.16)×109/L and the control group is(0.42±0.14)×109/L. Theperipheral blood lymphocyte countof the stroke groupis lower than the control group, the count of leukocyte, neutrophil and monocyte of the stroke group is higher than the brain tumor group and the control group, between group differences were statistically significant.3、Theperipheral blood leukocyte count of the stroke group who have pneumonia is(9.86±4.17)×109/L and the neutrophil count is(7.89±4.48)×109/L. Theperipheral blood leukocyte count of the stroke group who haveno pneumonia is(7.51±2.05)x 109/L and the neutrophil count is(5.16±1.98)×109/L. Theperipheral blood leukocyte and neutrophil count of the stroke group who havepneumoniaare higher than the oneswho have nopneumonia, between group differences were statistically significant.4、The spleen weight of mice in each group:the MCAO 24h group is(65±8)mg, the MCAO 48h group is(61±12)mg, the MCAO 72h group is(54±14)mg and the control group is(91±13)mg.The spleen weight index in each group:the MCAO 24h group is 28.94±3.76, the MCAO 48h group is 26.79±5.32, the MCAO 72h group is 23.74±7.66 and the control group is 39.46±5.60.The spleen cell countsin each group: the MCAO 24h group is(2.775±1.479)×107, the MCAO 48h group is(2.337±0.976)×107, the MCAO 72h group is(1.993±0.997)×107 and the control group is(7.155±2.052)×107.The spleen weight, spleen weight indexand spleen cell countsof the MCAO 24h,48h and 72h groupsare decreased than the control group, between group differences were statistically significant.5、The count ofthe inflammatory cells in lungof the stroke group miceis higher than the control group.6、The apoptosis index of spleen cellsof mice in each group:the stroke group is 20.00%±5.39% and the control group is 6.48%±1.37%. The apoptosis index of spleen cells of the stroke groupis higher than the control group, between group differences were statistically significant.ConclusionThe ischemic stroke patients were more susceptible to pneumonia, theperipheral blood leukocyte, neutrophil and monocyte count of the stroke group is increased and the lymphocyte count isdecreased. Theperipheral blood leukocyte and neutrophil count of the stroke group who havepneumoniaare higher than the oneswho have nopneumonia, and the stroke group mice have inflammatory reaction in lung. The spleen weight, spleen weight index and spleen cell counts of the stroke group mice are decreased andthe apoptosis index of spleen cells is increased, which suggest that there may immunodepressionafter ischemic stroke and easily lead to the infection,andthe apoptosis of lymphocytes may be one of the mechanismswhich cause immunodepressionafter ischemic stroke.