Morigi M, Zoja C, Figliuzzi M, Remuzzi G, Remuzzi A
Mario Negri Institute for Pharmacological Research, Ospedali Riuniti di Bergamo, Italy.
Am J Physiol. 1993 Apr;264(4 Pt 1):C1080-3. doi: 10.1152/ajpcell.1993.264.4.C1080.
We investigated the effects of culture medium conditioned with endothelial cells exposed to hemodynamic shear forces on modulation of mesangial cell (MC) growth. Confluent monolayers of bovine aortic endothelial cells, grown in medium containing 10% fetal calf serum, were exposed to static or to laminar flow conditions for 24 h using a cone-and-plate device. Endothelial cell-conditioned medium was used to study the growth of bovine MC by [3H]thymidine uptake. The proliferative response of MC to fresh medium (containing 10% fetal calf serum) and to culture medium from endothelial cells under static flow [66.7 +/- 34.1 vs. 73.9 +/- 30.0 counts/min (cpm) x 10(-3)] was comparable. In contrast, medium conditioned with endothelial cells exposed to laminar shear stress of 8 dyn/cm2 almost completely abolished MC proliferation (5.8 +/- 6.9 cpm x 10(-3), P < 0.01). To establish whether this effect is due to endothelial cell production of a substance that inhibits MC proliferation or simply to metabolization of serum growth factors in the culture medium, we performed shear stress experiments using serum free medium and we added 10% fetal calf serum after shear exposure just before the proliferation assay. In this condition a significant antiproliferative effect of endothelial cell supernatant under laminar flow was obtained (27.7 +/- 23.4 vs. 68.8 +/- 45.8 cpm x 10(-3), laminar vs. static, P < 0.05), suggesting that endothelial cells under shear stress effectively produce a factor that inhibits MC proliferation. These results would suggest that local glomerular capillary blood flow could play a role in the regulation of MC mitogenesis.
我们研究了经血流动力学剪切力作用的内皮细胞条件培养基对系膜细胞（MC）生长调节的影响。将生长于含10%胎牛血清培养基中的牛主动脉内皮细胞汇合单层，使用锥板装置使其暴露于静态或层流条件下24小时。采用[3H]胸腺嘧啶核苷摄取法，以内皮细胞条件培养基研究牛MC的生长情况。MC对新鲜培养基（含10%胎牛血清）和静态流动条件下内皮细胞培养基的增殖反应相当[66.7±34.1对73.9±30.0计数/分钟（cpm）×10⁻³]。相比之下，经8达因/平方厘米层流剪切应力作用的内皮细胞条件培养基几乎完全抑制了MC增殖（5.8±6.9 cpm×10⁻³，P<0.01）。为确定这种效应是由于内皮细胞产生了抑制MC增殖的物质，还是仅仅由于培养基中血清生长因子的代谢作用，我们使用无血清培养基进行了剪切应力实验，并在剪切暴露后、增殖测定前加入10%胎牛血清。在此条件下，获得了层流状态下内皮细胞上清液显著的抗增殖效应（27.7±23.4对68.8±45.8 cpm×10⁻³，层流对静态，P<0.05），表明剪切应力作用下的内皮细胞有效产生了一种抑制MC增殖的因子。这些结果提示局部肾小球毛细血管血流可能在MC有丝分裂的调节中发挥作用。
