食物限制对大鼠的肾脏转运和皮质膜脂质含量有有益影响。

Eiam-Ong S, Sabatini S

Department of Physiology and Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, USA.

J Nutr. 1999 Sep;129(9):1682-7. doi: 10.1093/jn/129.9.1682.

Food restriction (FR) exerts a variety of beneficial effects and may prolong life in both humans and animals. However, studies of its effects on the cortical brush border membrane (BBM) and basolateral membrane (BLM) lipid concentration, which may be pertinent to renal function, have not been reported in detail. We hypothesized that FR would decrease renal work and lower renal membrane lipid concentration. The changes in lipid concentration would be most dramatic in BBM because this membrane is the entry site for the recovery of filtered ions and nutrients. Young male Fischer 344 x Brown-Norway F1 rats consumed food ad libitum (AL) or were food-restricted (FR, 60% of AL consumption) for 6 wk. AL rats had higher fractional excretions of Na(+), K(+), and Cl(-) than did the FR group (P < 0.001). Renal Na,K-ATPase activity in AL rats was 100% higher than in FR rats (P < 0.001), reflecting greater renal work. The work required for renal proton secretion was lower in FR than in the AL rats. In FR rats, all BBM phospholipid concentrations (phosphatidylserine, phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin) were approximately 50% lower than in the AL rats (P < 0.001). In the BLM, food restriction resulted only in lower phosphatidylcholine concentration, while the other phospholipids were unaffected. Plasma and renal membrane (BBM and BLM) cholesterol concentrations were significantly lower in FR than in AL rats. These results show that a nutritionally complete, but energy restricted, diet improves renal function. It also prevents renal membrane lipid deposition and decreases plasma cholesterol. Prolonged food restriction might attenuate the renal injury that occurs in obese humans as a consequence of insulin resistance and atherosclerosis.

食物限制（FR）具有多种有益作用，可能会延长人类和动物的寿命。然而，关于其对皮质刷状缘膜（BBM）和基底外侧膜（BLM）脂质浓度的影响（这可能与肾功能相关）的研究尚未详细报道。我们推测，食物限制会减少肾脏工作并降低肾膜脂质浓度。脂质浓度的变化在BBM中最为显著，因为该膜是滤过离子和营养物质重吸收的入口部位。将年轻雄性Fischer 344×Brown-Norway F1大鼠分为两组，一组随意进食（AL），另一组进行食物限制（FR，进食量为AL组的60%），持续6周。AL组大鼠的Na⁺、K⁺和Cl⁻分数排泄率高于FR组（P<0.001）。AL组大鼠的肾钠钾ATP酶活性比FR组高100%（P<0.001），这反映出肾脏工作负担更重。FR组大鼠肾脏质子分泌所需的工作量低于AL组大鼠。在FR组大鼠中，所有BBM磷脂浓度（磷脂酰丝氨酸、磷脂酰胆碱、磷脂酰乙醇胺和鞘磷脂）均比AL组大鼠低约50%（P<0.001）。在BLM中，食物限制仅导致磷脂酰胆碱浓度降低，而其他磷脂不受影响。FR组大鼠的血浆和肾膜（BBM和BLM）胆固醇浓度显著低于AL组大鼠。这些结果表明，营养完整但能量受限的饮食可改善肾功能。它还可防止肾膜脂质沉积并降低血浆胆固醇。长期食物限制可能会减轻肥胖人群因胰岛素抵抗和动脉粥样硬化而发生的肾损伤。