Mechanism of brain-spleen inflammation coupling in a rat model of acute ischemic stroke stasis toxin syndrome / 中国比较医学杂志

ABSTRACT

Objective To investigate the correlation between brain injury and spleen damage in a rat model of acute ischemic stroke and stasis interaction,and its effect on the MCP-1/CCR2 axis,and to provide an experimental basis for the mechanism of brain-spleen inflammatory coupling in spleen lesions caused by acute ischemic stroke.Methods Forty male SD rats were randomly divided into a sham group,carrageenan/yeast stasis syndrome group(carrageenan/yeast,CA/Y),middle cerebral artery occlusion group(MCAO),and middle cerebral artery stasis syndrome group(MCAO CA/Y)with 10 rats in each group.CA/Y and MCAO CA/Y groups were injected with 10 mg/kg carrageenan and 10 mg/kg intraperitoneally on the first day of modeling.2 mg/kg of dry yeast suspension were injected subcutaneously on the second day.MCAO and MCAO CA/Y groups were established by wire embolism on the second day.At 24 h after cerebral infarction modeling,the neurological deficit score was calculated in each group,the percentage of the cerebral infarction area was determined by TTC staining,the spleen weight was measured,and the correlation between the percentage of the cerebral infarction area and spleen weight was analyzed by the Spearman correlation coefficient.Furthermore,the pathological morphology of brain and spleen tissues was observed by hematoxylin-eosin(HE)staining,and chemotactic protein 1(MCP-1)and interferon-γ(IFN-γ)contents were measured in rat plasma by enzyme-linked immunosorbent assays.Western blot was used to detect chemokine C-C-motif receptor 2(CCR2)protein expression in the ischemic side of brain tissue.Results Compared with the sham group,the neurological deficit score,cerebral infarction area,and MCP-1 and IFN-γ contents in plasma were significantly increased(P＜0.01),spleen weight was decreased significantly(P＜0.01),and CCR2 protein expression in brain tissue was significantly upregulated(P＜0.05)in MCAO and MCAO CA/Y groups.Moreover,the area of cerebral infarction was increased significantly(P＜0.01),the spleen weight was decreased significantly(P＜0.01),and CCR2 protein expression in brain and spleen tissues was significantly upregulated(P＜0.05)Compared with the MCAO group,the area of cerebral infarction in the MCAO CA/Y group was significantly increased(P＜0.01)and the spleen weight was decreased significantly(P＜0.05).Spearman correlation analysis showed that the spleen weight was negatively correlated to the percentage of the cerebral infarction area(P＜0.01,r=-0.9711).Pathological morphology observation revealed that the pathological changes in the MCAO CA/Y group were the most serious,cerebral liquefaction necrosis foci were seen in the brain tissue cortex,arrangement of neuronal cells in the lesions was sparse and disordered with volume atrophy and a small number of vacuoles and nuclear solidification,most neuronal cells were degenerated and necrotic,microglia hyperplasia was obvious,small blood vessels were significantly increased,and interstitial lipid degeneration was severe.The density of periarterial lymph sheath cells in some of the spleen tissue was reduced and the marginal area is widened.Conclusions A correlation between brain and spleen injury was found after acute ischemic stroke with stasis and toxin syndrome,and the chemokine signaling axis of MCP-1/CCR2 might be involved in the mechanism of brain-spleen inflammation coupling.