Bigelow M W, Wiessner J H, Kleinman J G, Mandel N S
Department of Medicine, Medical College of Wisconsin and Department of Veterans Affairs Medical Center, Milwaukee 53295, USA.
J Urol. 1998 Oct;160(4):1528-32.
Cultured kidney epithelial cell lines have frequently been used in urolithiasis research, and in particular in studies related to the interactions between stone crystals and cell membranes. There is evidence that when epithelial cell lines are transformed or serially passed to immortalize them, they experience changes in both cell physiology and morphology. Stone research utilizing cell cultures is frequently necessary due to the lack of an animal model for spontaneous stone disease. However, the interpretation of these cell culture research studies might be clouded by any significant differences in cell physiology between primary cells and continuous cell cultures. Therefore, the present study was conducted to compare calcium oxalate monohydrate (COM) crystal attachment to two primary kidney epithelial cell lines and to various continuous cell lines.
The cell lines surveyed were primary mouse proximal tubule cells (pMPT), primary inner medullary collecting duct cells (pIMCD), semi-continuous inner medullary collecting duct cells (cIMCD), BSC-1 cells, COS-1 cells, LLC-PK1 cells, MDCK cells, NRK-52E cells, and OK cells. All cell lines were cultured under identical conditions and the amount of COM attachment was measured using radioactive labeled COM crystals.
COM crystal interaction with continuous kidney epithelial cells varied by a factor of two among the different cell lines. In general, cells that grew as regular, confluent cell monolayers, such as pMPT, pIMCD and cIMCD cells, exhibited the lowest levels of crystal attachment. Neither changes in membrane fluidity nor loss of normal epithelial cell membrane asymmetry seemed to correlate well with crystal attachment. After nine days of continuous cell culture, COM attachment to cIMCD cells dropped by 61 percent while crystal attachment to MDCK cells remained unchanged. It is unclear what makes these cell lines more resistant to crystal attachment compared to continuous cell lines.
The significant difference in COM attachment between primary kidney epithelial cells and continuous epithelial cell cultures and the apparent differences in growth morphology between primary and continuous cell cultures must be considered when selecting a cell line for use in kidney stone research. Comparison of cIMCD cells and MDCK cells during extended culture time revealed one possible explanation for the differences in COM attachment: the formation of a mature, end-differentiated, non-dividing cell monolayer could protect the cells from crystal attachment.
培养的肾上皮细胞系经常用于尿路结石研究，尤其是在与结石晶体和细胞膜相互作用相关的研究中。有证据表明，当上皮细胞系被转化或连续传代以使其永生化时，它们的细胞生理学和形态都会发生变化。由于缺乏自发性结石病的动物模型，利用细胞培养进行结石研究常常是必要的。然而，这些细胞培养研究的解释可能会因原代细胞和连续细胞培养之间细胞生理学的任何显著差异而受到影响。因此，本研究旨在比较一水合草酸钙（COM）晶体与两种原代肾上皮细胞系以及各种连续细胞系的附着情况。
所研究的细胞系包括原代小鼠近端小管细胞（pMPT）、原代髓质内集合管细胞（pIMCD）、半连续髓质内集合管细胞（cIMCD）、BSC-1细胞、COS-1细胞、LLC-PK1细胞、MDCK细胞、NRK-52E细胞和OK细胞。所有细胞系均在相同条件下培养，并使用放射性标记的COM晶体测量COM附着量。
COM晶体与连续肾上皮细胞的相互作用在不同细胞系之间相差两倍。一般来说，以规则、汇合的细胞单层生长的细胞，如pMPT、pIMCD和cIMCD细胞，表现出最低水平的晶体附着。膜流动性的变化和正常上皮细胞膜不对称性的丧失似乎都与晶体附着没有很好的相关性。连续细胞培养九天后，COM与cIMCD细胞的附着下降了61%，而晶体与MDCK细胞的附着保持不变。与连续细胞系相比，不清楚是什么使这些细胞系对晶体附着更具抗性。
在选择用于肾结石研究的细胞系时，必须考虑原代肾上皮细胞和连续上皮细胞培养物之间COM附着的显著差异以及原代和连续细胞培养物之间明显的生长形态差异。在延长培养时间期间对cIMCD细胞和MDCK细胞的比较揭示了COM附着差异的一种可能解释：成熟的、终末分化的、不分裂的细胞单层的形成可以保护细胞免受晶体附着。
