Analysis of serum factor that is related to glomerular hypertrophy and extracellular matrix metabolism.

众所周知，5/6肾切除术后残肾可见肾小球硬化和肾小球肥大。以往的研究表明，残肾代偿性肥大是由血清因子(S)介导的，也就是所谓的肾性因子。然而，肾小球肥大是否由同一因素介导，目前尚不清楚。在动物实验中，当输尿管分流术减少功能性肾单位肿块时，未观察到肾小球肥大。生长激素缺乏大鼠行5/6肾切除时，未见肾小球肥大。本研究用体外培养的肾小球系膜细胞评价肾大部切除动物血清对肾小球硬化和肾小球肥大的影响。加入肾切除血清后，以胸腺嘧啶核苷摄取评价的增殖反应略有增加，尤其是在相对分子质量小于3000的部分。Northern印迹分析评价细胞外基质代谢，对血清无明显影响。用凝胶收缩法研究了细胞与基质的相互作用，5/6肾切除小鼠的血清使凝胶收缩增强。综上所述，肾小球肥大的5/6肾切除动物的血清中存在一些影响系膜细胞行为的因素。然而，它不能证明血清对细胞外基质代谢的影响。

It has been well known that glomerular sclerosis and glomerular hypertrophy observe in the remnant kidney after 5/6 nephrectomy. Previous studies indicated that compensatory hypertrophy of the remnant kidney was mediated by serum factor (s), so called renotropic factor. However, it is not clarified whether glomerular hypertrophy is mediated by same factor or not. In the animal experiments, glomerular hypertrophy did not observe when functioning nephron mass were reduced by ureteral diversion. When 5/6 nephrectomy performed using growth hormone deficient rats, glomerular hypertrophy did not observe. In this study, effects of the sera obtained from subtotally nephrectomized animal, in which glomerular sclerosis and glomerular hypertrophy were observed, were evaluated using cultured mesangial cells. The proliferative response evaluated by thymidine uptake were slightly increased by adding the nephrectomized serum, especially in the fraction of MW less than 3000. Concerning about the extra cellular matrix metabolism evaluated by northern blot analysis, there were no obvious effects in the sera. Cell-matrix interactions were studied by using gel contraction method, and the sera from 5/6 nephrectomized mice increased gel contraction. In conclusion, some factors that affect mesangial cell behavior present in the serum obtained from 5/6 nephrectomized animal in which glomerular hypertrophy observe. However it was not able to demonstrate the effects of the sera to extra cellular matrix metabolism.