Yu Hongmei, Alexander Caroline M, Beebe David J
Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA.
Lab Chip. 2007 Jun;7(6):726-30. doi: 10.1039/b618793e. Epub 2007 Apr 19.
While the importance of autocrine-paracrine signaling in vivo is clear, the ability to study the effects of secreted endogenous factors in vitro is hampered by canonical culture platforms. In multi-well plates, the large air-liquid interface gives rise to convective flows that continually mix the fluid disrupting the local diffusion-based accumulation. Simple microchannels provide a more controlled microenvironment that can be used to study secreted factor effects. Here, we utilize microchannel culture to examine basic culture parameters and their interactions using normal mammary gland epithelial cells (NMuMG). The following parameters were studied: (1) cell density (80 vs. 240 cells mm(-2)), (2) exogenous growth factors (epidermal growth factor [EGF] vs. fetal bovine serum), (3) medium change frequency (1 h, 4 h, 12 h), and (4) culture platform (microchannels vs. 96-well plates). The cells exhibited increased growth rates in microchannels as compared to 96-well plates. Cell proliferation increased as the frequency of media change decreased. For the microchannel geometries used, important threshold concentrations were reached in a few hours. In aggregate, the results indicate that the function of the four factors and their interactions on NMuMG growth are spatially and temporally related by molecular diffusion in the controlled microchannel space. The convective-free microchannel environment may prove useful for studying soluble factor signaling in vitro, and to test models and predictions of autocrine-paracrine signaling.
虽然自分泌 - 旁分泌信号在体内的重要性已很明确，但传统培养平台阻碍了在体外研究分泌型内源性因子作用的能力。在多孔板中，较大的气液界面会产生对流，持续混合液体，破坏基于局部扩散的积累。简单的微通道提供了一个更可控的微环境，可用于研究分泌因子的作用。在此，我们利用微通道培养，使用正常乳腺上皮细胞（NMuMG）来研究基本培养参数及其相互作用。研究了以下参数：（1）细胞密度（80对240个细胞/mm²），（2）外源性生长因子（表皮生长因子[EGF]对胎牛血清），（3）培养基更换频率（1小时、4小时、12小时），以及（4）培养平台（微通道对96孔板）。与96孔板相比，细胞在微通道中表现出更高的生长速率。随着培养基更换频率降低，细胞增殖增加。对于所使用的微通道几何形状，在数小时内就达到了重要的阈值浓度。总体而言，结果表明这四个因素及其对NMuMG生长的相互作用的功能，在可控的微通道空间中通过分子扩散在空间和时间上相关。无对流的微通道环境可能被证明对体外研究可溶性因子信号传导以及测试自分泌 - 旁分泌信号传导的模型和预测有用。
