缓激肽对人角质形成细胞增殖凋亡及分化影响的实验研究

目的观察缓激肽(BK)对体外培养的人角质形成细胞(HKC)增殖、凋亡和分化的影响并探讨其机制。方法以1×10-4~1×10-9mol/LBK作用于体外培养的HKC,采用噻唑蓝法、台盼蓝染色法观察到1×10-4mol/LBK抑制作用最强,以此浓度BK进行余下实验。当HKC达对数生长期后,一部分加入1×10-4mol/LBK作为实验组,另一部分不加BK作为对照组,分别培养24、48h后采用流式细胞仪检测细胞早期凋亡情况及细胞周期,用链霉亲和素-生物素复合物(SABC)免疫细胞化学法检测HKC分化标志物角蛋白10(K10)及内披蛋白的表达情况。用含1×10-4mol/LBK的无血清培养基KC-SFM培养HKC作为实验组,对照组细胞仅加KC-SFM,分别用激光扫描共聚焦显微镜结合钙荧光探针Fluo-3/AM技术检测细胞内游离Ca2 浓度即[Ca2 ]i的变化。结果与对照组比较,实验组G0/G1期细胞比例相对上升34.57%,S期相对下降58.91%,其细胞早期凋亡率为15.34%,明显高于对照组(5.60%,P<0.05)。实验组HKCK10阳性细胞百分比为2.20%,明显低于对照组(6.89%,P<0.05)。BK作用3min后实验组HKC[Ca2 ]i较对照组上升163.0%,之后开始下降,5min后接近对照组。结论高浓度BK可抑制HKC周期进程、明显促进其凋亡及诱导[Ca2 ]i升高,这可能是其使HKC体外生长受抑的部分机制。BK还可抑制表皮再生和HKC分化。

Effects of bradykinin on the proliferation, apoptosis and differentiation of human keratinocytes

OBJECTIVE: To investigate the effects of bradykinin (BK) on the proliferation, apoptosis and differentiation of human keratinocyte (HKC) and the underlying mechanisms. METHODS: HKCs were cultured together with 1 x 10(-4) - 1 x 10(-9) mol/L of BK. With methyl thiotetrazole (MTT) and trypan blue staining it was shown that the BK in dose of 1 x 10(-4) mol/L possessed most powerful inhibitory effect, and the survival rate of HKC was 69.3%. Therefore, BK was employed in the dose of 1 x 10(-4) mol/L in the following studies. When the growth of HKCs reached the logarithmic phase, BK in the concentration of 1 x 10(-4) mol/L was added, and it was categorized as the test group (E). HKCs without BK served as the control group (C). The cell cycle and apoptosis were detected by flow cytometry after being cultured for 24 and 48 hours. The change in intracellular calcium [Ca(2+)](i) was determined by means of laser scanning confocal microscopy with calcium fluorescence probe Fluo-3/AM techique. The expression of HKC differentiation labeling protein keratin10 (K10) and involucrin were detected with Strept Avidine-Biontin Complex (SABC) immunocytochemical assay. RESULTS: The cell ratio in G0/G1 phase in E group increased by 34.57% while in S phase decreased by 58.91% in reference to that in C group. The G1/S phase switching of HKCs was obviously inhibited by BK, and apoptosis was stimulated (apoptotic rate of 15.34% in E group vs 5.60% in C group, P < 0.05). The [Ca(2+)](i) increased transiently in HKCs by 163.0% in E group after 3 minutes of BK activation and decreased thereafter in reference to that in C group. The K10 expression in HKC was down-regulated in E group with positive cell rate of 2.20%, which was lower than that of C group (6.89%, P < 0.05). CONCLUSION: The cell cycle process of HKC could be inhibited by high concentration of BK with increased apoptosis and an increase in [Ca(2+)](i), which might be the mechanism of inhibition of growth of HKC in vitro. Furthermore, the epithelial regeneration and HKC differentiation can also be inhibited by BK.