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目的:研究人巨噬细胞发育及其向泡沫细胞分化过程中MaxiK通道的表达和电生理学特征。方法:以健康人外周血单核细胞源性巨噬细胞为研究对象,采用Real time RT-PCR和Western blot技术观察MaxiK通道α亚单位mRNA及蛋白的表达;膜片钳技术分析MaxiK通道的电生理学特征。结果:在巨噬细胞发育过程中,MaxiK通道α亚单位的表达被轻度上调。同培养5 d的细胞相比,7.5 d细胞的mRNA及蛋白表达增加分别约为1.06和1.44倍,但无统计学意义。然而,30 mg/L oxLDL显著提高MaxiK通道α亚单位的表达,在其分化成泡沫细胞后,mRNA和蛋白表达分别是培养5 d细胞的2.4和7.27倍,有显著的差异(P<0.05)。在所有培养5 d、7.5 d和oxLDL组中的巨噬细胞上均能记录到典型的MaxiK电流;MaxiK通道的选择性阻断剂-paxilline(10μmol/L)抑制时间依从性电流、几乎全部的外向电导和噪声;但是,在培养5 d、7.5 d和oxLDL组中的巨噬细胞上MaxiK电流密度分别是(36±6)pA/pF、(35.9±3.5)pA/pF和(32.4±6.9)pA/pF,无明显差异。结论:在人巨噬细胞发育过程中,MaxiK通道的表达被上调,分化成泡沫细胞后尤为显著,但其介导的电流没有改变。
AIM: To investigate the expression and electrophysiological characteristics of MaxiK channel in human macrophage development and its differentiation into foam cells. Methods: Monocyte-derived macrophages from healthy volunteers were used as experimental subjects. Real-time RT-PCR and Western blotting were used to detect mRNA and protein expression of MaxiK channel α subunit. Patch-clamp technique was used to analyze MaxiK channels Physiological characteristics. Results: The expression of the MaxiK channel alpha subunit was slightly up-regulated during macrophage development. Compared with the 5-day culture, the mRNA and protein expression of 7.5-day-old cells increased by about 1.06 and 1.44-fold, respectively, but not statistically significant. However, 30 mg / L oxLDL significantly increased the MaxiK channel α subunit expression. After differentiation into foam cells, mRNA and protein expression were 2.4 and 7.27 folds, respectively, with significant difference (P <0.05) . Typical MaxiK currents were recorded on all macrophages in the 5-day, 7.5-day and oxLDL-treated groups. Paxilline (10 μmol / L), a selective blocker of the MaxiK channel, suppressed time-dependent currents and almost all Extrinsic conductance and noise; however, the MaxiK current densities on macrophages in the 5 d, 7.5 d and oxLDL groups were (36 ± 6) pA / pF, (35.9 ± 3.5) pA / pF, and (32.4 ± 6.9 ) pA / pF, no significant difference. CONCLUSION: The expression of MaxiK channel is up-regulated during human macrophage development, especially after differentiation into foam cells, but its current-mediated changes have not changed.