Hansen U, Schünke M, Domm C, Ioannidis N, Hassenpflug J, Gehrke T, Kurz B
Anatomisches Institut der Christian-Albrechts-Universität Kiel, Olshausenstr. 40, D-24098, Kiel, Germany.
J Biomech. 2001 Jul;34(7):941-9. doi: 10.1016/s0021-9290(01)00050-1.
Cartilage cells are normally studied under atmospheric pressure conditions and without loading. However, since cartilage exists in a condition of reduced oxygen and intermittent hydrostatic pressure we hypothesized lower partial oxygen pressures (PO2) and different intermittent hydrostatic pressures (IHP) would increase articular chondrocyte proliferation and matrix production and to stabilize chondrocyte phenotype in vitro. Monolayers of adult bovine articular chondrocytes were cultured under 5% or 21% PO2 in combination with IHP (0.2 MPa amplitude, frequencies 5/5s = 0.1 Hz, 30/2 or 2/30 min on/off loading). We measured proliferation (3H-thymidine incorporation) and collagen secretion (protein-binding assay, collagen type II-ELISA and immunocytochemical staining of pericellular collagen types I, II and IX). Reduced PO2 stimulated proliferation and collagen type II and IX secretion of chondrocytes in comparison to 21% PO2. Additionally, collagen type I expression was delayed by low PO2, indicating a stabilization of the cell phenotype. IHP 5/5s and 30/2 min inhibited proliferation but increased collagen secretion (pericellular collagen type IX was decreased). IHP 30/2 min delayed first expression of collagen type I. In contrast, IHP 2/30 min increased proliferation, but lowered collagen expression. All stimulating or inhibiting effects of PO2 and IHP were additive and vice versa. Reduced PO2 and different settings of IHP increased proliferation, collagen secretion, and phenotype stability of chondrocytes. The oxygen- and IHP-induced effects were additive, suggesting that a combination of these parameters might be a useful tool in cartilage tissue engineering.
软骨细胞通常在常压条件下且无负荷状态下进行研究。然而，由于软骨存在于低氧和间歇性静水压力环境中，我们推测较低的氧分压（PO2）和不同的间歇性静水压力（IHP）会增加关节软骨细胞的增殖和基质产生，并在体外稳定软骨细胞表型。将成年牛关节软骨细胞单层培养于5%或21% PO2环境中，并结合IHP（振幅0.2 MPa，频率5/5秒 = 0.1 Hz，30/2或2/30分钟开/关加载）。我们测量了细胞增殖（3H-胸腺嘧啶核苷掺入）和胶原蛋白分泌（蛋白质结合测定、II型胶原蛋白酶联免疫吸附测定以及细胞周围I、II和IX型胶原蛋白的免疫细胞化学染色）。与21% PO2相比，降低的PO2刺激了软骨细胞的增殖以及II型和IX型胶原蛋白的分泌。此外，低PO2延迟了I型胶原蛋白的表达，表明细胞表型得到了稳定。IHP 5/5秒和30/2分钟抑制了增殖，但增加了胶原蛋白分泌（细胞周围IX型胶原蛋白减少）。IHP 30/2分钟延迟了I型胶原蛋白的首次表达。相反，IHP 2/30分钟增加了增殖，但降低了胶原蛋白表达。PO2和IHP的所有刺激或抑制作用都是相加的，反之亦然。降低的PO2和不同设置的IHP增加了软骨细胞的增殖、胶原蛋白分泌和表型稳定性。氧和IHP诱导的效应是相加的，这表明这些参数的组合可能是软骨组织工程中的一种有用工具。
