乳腺癌特异性磁共振分子探针的制备及体外实验

目的：制备针对乳腺癌细胞表面生长激素抑制素受体(somatostatin receptor, SSTR)的特异性磁共振分子探针，探讨其理化性质及体外成像特征。方法：采用化学偶联法，将超顺磁性氧化铁颗粒（superparamagnetic iron oxide, SPIO）与生长激素抑制素类似物奥曲肽(octreotide, OCT)偶联，制备特异性磁共振分子探针SPIO-OCT。用MTT法分析不同浓度探针对标记细胞生长增殖的影响，普鲁士蓝染色评价其细胞磁性标记情况，并对不同浓度的探针、不同数目的标记细胞行体外磁共振成像。细胞磁性标记对照组采用超顺磁性氧化铁颗粒（Resovist）。结果：细胞被分子探针磁性标记后，胞质内可见蓝染颗粒，且探针标记浓度越高，胞质内蓝染颗粒越多；分子探针细胞阳性标记率达96.15%，高于对照组（80.00%）；MTT结果显示，不同浓度的探针对细胞增殖影响差异无统计学意义（P＞0.05）；探针在Fe²⁺ 浓度为20 mg/L时，T₂WI呈明显低信号、无磁敏感伪影，此浓度标记的细胞数量越多，T2WI信号降低越明显，6×10⁶个磁标记细胞T₂WI上呈显著低信号。结论：磁共振分子探针SPIO-OCT可安全、高效标记SSTR表达阳性的乳腺癌细胞，其理想标记和成像浓度为Fe²⁺ 20 mg/L，体外核磁信号强度可在一定程度上反应磁标记细胞的数量。

Preparation of magnetic resonance molecular probe for breast cancer detection in vitro

Objective:To prepare magnetic resonance(MR) molecular probe for somatostain receptor expressed on breast cancer cell membranes and investigate its physico-chemical properties and imaging features in vitro.Methods:Molecular probe was prepared through superparamagnetic iron oxide(SPIO) conjugated to somatostatin analog-octreotide(OCT) using chemical method.Its features at different Fe2+ concentrations were tested by MTT assay and Prussian blue staining respectively.Molecular probes at di-fferent Fe2+ concentr...