星形细胞瘤MRI定量参数与HIF-1α表达水平的相关性分析

Correlation analysis on MRI quantitative parameters and expression level of HIF-1α in cerebral astrocytoma

目的:探讨星形细胞瘤MRI定量参数与缺氧诱导因子1α(HIF-1α)表达水平的相关性,阐明MRI定量参数与星形细胞瘤相关指标的关系。方法:收集手术病理证实的脑星形细胞瘤33例,计算MRI定量分析指标水肿指数(EI)、T1WI增强后相对信号强度(RSIGd)及信号强度增加百分率(EP)。采用免疫组织化学法检测HIF-1α的表达情况。结果:低级别星形细胞瘤(WHOⅠ-Ⅱ级)的平均RSIGd值、EP值均低于高级别星形细胞瘤(WHOⅢ-Ⅳ级)(均P<0.01)。低级别星形细胞瘤平均EI值低于高级别星形细胞瘤(P<0.01);正常脑组织中未见HIF-1α表达,各级星形细胞瘤中均有HIF-1α表达,其表达强度随星形细胞瘤病理级别增高而加强,低级别星形细胞瘤平均HIF-1α表达水平低于高级别星形细胞瘤(P<0.001);HIF-1α表达水平与RSIGd和EP值呈正相关关系(r=0.431,P<0.05;r=0.651,P<0.001),HIF-1α表达水平与EI值无明显相关性(r=0.317,P>0.05)。结论:RSLGd、EP可以较好地反映脑星形细胞瘤新生血管的通透性和病理分级,病理级别高的肿瘤易伴瘤周水肿,但瘤周水肿不能用单一一种理论解释。

Objective To clarify the relationship between MRI quantitative parameters and astrocytoma related indexes by analyzing the correlation between MRI quantitative parameters and the expression level of hypoxia inducible factor-1α （HIF-1α） in cerebral astrocytoma. Methods A total of 33 cases of astrocytoma proved by operation and pathology were collected. The MRI quantitative parameters, such as edema index （EI）, relative signal intensity on Gd-enhanced T1WI （RSIGd） and enhancement percentage （EP） were measured. The expression of HIF-1α in tumor tissues was detected with immunohistochemical method. Results The values of RSIGd and EP of low grade astrocytoma （WHO grade Ⅰ - Ⅱ ） were significantly lower than those of high grade astrocytoma （WHO grade Ⅲ-Ⅳ） （P〈O. 01）. The EI value of low grade astrocytoma was lower than that of high grade astrocytoma （P〈0.01）. There was no expression of HIF-1α in normal brain tissue. But HIF-1α expressed in astrocytoma with different grades. The expression level of HIF-1α in low grade astrocytoma was lower than that in high grade astrocytoma （P〈0. 001）. The expression level of HIF-1α was positively correlated with the value of RSIGd （r= 0. 431, P〈0. 05）. The expression level of HIF-1α was significantly positively correlated with the value of EP （r= 0. 651, P〈0. 001）. There was no obviously significant correlation between the level of HIF-1α and the value of EI （r= 0. 317, P〉0.05）.Conclusion RSIGd and EP are very helpful to evaluate the pathological grades and the permeability of new vessels of cerebral astrocytoma. High grade cerebral astrocytomas are often accompanied by peritumoral edema but it can＇ t be explained by only one theory.