Correlation Of Monocyte Chemoattractant Protein-1 Expression And Brain Edema In Rats After Experimental Intracerebral Hemorrhage

BackgroundChemokines have been shown to play an important role in leukocyte infiltration into hemorrhagic lesions. Recently, the increased expression of monocyte chemoattractant protein-1 (MCP-1) was observed in experimental SAH and MCAO models where infiltrated leukocytes were supposed to induce tissue injury. However, the role of MCP-1 in the brain edema after intracerebral hemorrhage (ICH) in rats has not been explored. This study was understaken to investigate the expression of MCP-1 in ICH model and to clarify the relationship of MCP-1 in brain edema.MethodsA total of 167 male Sprague-Dawley rats were randomly divided into 7 groups:control group; 2 hours,6 hours,12 hours,1 day,3 days and 7 days groups. The animals in control groups were subjected to physiological saline injection into ipsilateral basal ganglia (IBG), and the other animals were subjected to autologous blood injection into IBG and were killed 2 hours,6 hours,12 hours,1 day,3 days and 7 days after ICH. Brain water content of IBG, contralateral basal ganglia (CBG) and cerebellum (C) was measured and the MCP-1 protein and mRNA expression was assessed by enzyme-linked immunosorbent assay systems (ELISA), Western blot (WB), reverse transcription and polymerase chain reaction (RT-PCR). The experiment details are shown in the appendant figure. ResultsThe brain water content of IBG was found to be 78.702±0.065% at 2h,79.305±0.139% at 6h,80.425±0.409% at 12h,81.355±0.425% on Id,82.598±0.311% on 3d, and 80.625±0.512% on 7d, respectively, which reached to the peak point on 3d. The elevated protein of MCP-1 was detected after ICH and reached to the peak concentration at 12h in blood (155.855±29.407 pg/ml), at 6h in CSF (594.068±14.440 pg/ml), at 12h in IBG (371.458±12.324 ng/g tissue wet weight), statistical analysis showed that it was in accordance with WB and RT-PCR results. Correlation analysis revealed that MCP-1 is strongly positvely correlated with the development of brain edema at early stage (before 12h) in a rat ICH model.ConclusionOur study have described the different time-dependent production of MCP-1 in the blood, CSF and IBG in experimental ICH model. The peak local MCP-1 concentration was high enough to exert its biological effects, and that MCP-1 in hemorrhagic brain was actually related to the development of inflammatory response, and played a strongly positvie correlated role for regional brain edema formation at early stage.In addition, the present data also supported the possibility that different temporal MCP-1 production contributes to subsequent variation of infiltrated leukocyte subtypes.