Weinberg J M
J Clin Invest. 1985 Sep;76(3):1193-208. doi: 10.1172/JCI112075.
The utility of freshly isolated suspensions of rabbit tubules enriched in proximal segments for studying the pathogenesis of oxygen deprivation-induced renal tubular cell injury was evaluated. Oxygenated control preparations exhibited very good stability of critical cell injury-related metabolic parameters including oxygen consumption, cell cation homeostasis, and adenine nucleotide metabolism for periods in excess of 2 h. Highly reproducible models of oxygen deprivation-induced injury and recovery were developed and alterations of injury-related metabolic parameters in these models were characterized in detail. When oxygen deprivation was produced under hypoxic conditions, tubules sustained widespread lethal cell injury and associated metabolic alterations within 15-30 min. However, when oxygen deprivation was produced under simulated ischemic conditions, tubules tolerated 30-60 min with only moderate amounts of lethal cell injury occurring, a situation similar to that seen with ischemia in vivo. Like ischemia in vivo, simulated ischemia in vitro was characterized by a fall in pH during oxygen deprivation. No such fall in pH occurred in the hypoxic model. To test whether this fall in pH could contribute to the protection seen during simulated ischemia in vitro, tubules were subjected to hypoxia at medium pHs ranging from 7.45 to 6.41. Striking protection from hypoxic injury was seen as pH was reduced with maximal protection occurring in tubules made hypoxic at pHs below 7.0. Measurements of injury-associated metabolic parameters suggested that the protective effect of reduced pH may be mediated by pH-induced alterations of tubule cell Ca++ metabolism. This study has, thus, defined and characterized in detail a new and extremely versatile model system for the study of oxygen deprivation-induced cell injury in the kidney and has established that pH alterations play a major role in modulating such injury.
评估了富含近端小管节段的新鲜分离的兔肾小管悬浮液在研究缺氧诱导的肾小管细胞损伤发病机制中的效用。充氧对照制剂在超过2小时的时间内，关键细胞损伤相关代谢参数（包括耗氧量、细胞阳离子稳态和腺嘌呤核苷酸代谢）表现出非常好的稳定性。建立了高度可重复的缺氧诱导损伤和恢复模型，并详细表征了这些模型中损伤相关代谢参数的变化。当在低氧条件下产生缺氧时，肾小管在15 - 30分钟内持续出现广泛的致死性细胞损伤及相关代谢改变。然而，当在模拟缺血条件下产生缺氧时，肾小管可耐受30 - 60分钟，仅发生少量致死性细胞损伤，这一情况与体内缺血所见相似。与体内缺血一样，体外模拟缺血的特征是缺氧期间pH值下降。低氧模型中未出现这种pH值下降。为了测试这种pH值下降是否有助于体外模拟缺血期间所见的保护作用，将肾小管置于pH值范围为7.45至6.41的培养基中进行缺氧处理。随着pH值降低，可见对缺氧损伤的显著保护作用，在pH值低于7.0的肾小管中进行缺氧处理时出现最大保护作用。对损伤相关代谢参数的测量表明，pH值降低的保护作用可能是由pH值诱导的肾小管细胞Ca++代谢改变介导的。因此，本研究详细定义并表征了一种用于研究肾脏缺氧诱导细胞损伤的新型且极其通用的模型系统，并确定pH值改变在调节此类损伤中起主要作用。
