Department of Medicine, VA San Diego Healthcare System, University of California San Diego, San Diego, California, USA.
CVMR and PH Discovery, Janssen Research and Development, LLC, Cambridge, Massachusetts, USA.
Nephron. 2024;148(9):631-642. doi: 10.1159/000536522. Epub 2024 Feb 1.
ob/ob mice are a leptin-deficient type 2 diabetes mellitus model, which, on a BTBR background, mimics the glomerular pathophysiology of diabetic nephropathy (DN). Since leptin deficiency reduces blood pressure (BP) and endothelial nitric oxide synthase (eNOS) lowers BP and is kidney protective, we attempted to develop a more robust DN model by introducing eNOS deficiency in BTBR ob/ob mice.
Six experimental groups included littermate male and female BTBR ob/ob or wild-type for ob (control) as well as wild-type (WT), heterozygote (HET), or knockout (KO) for eNOS. Systolic BP (by automated tail-cuff) and GFR (by FITC-sinistrin plasma kinetics) were determined in awake mice at 27-30 weeks of age, followed by molecular and histological kidney analyses.
Male and female ob/ob WT presented hyperglycemia and larger body and kidney weight, GFR, glomerular injury, and urine albumin to creatinine ratio (UACR) despite modestly lower BP versus control WT. These effects were associated with a higher tubular injury score and renal mRNA expression of NGAL only in males, whereas female ob/ob WT unexpectedly had lower KIM-1 and COL1A1 expression versus control WT, indicating sex differences. HET for eNOS did not consistently alter BP or renal outcome in control or ob/ob. In comparison, eNOS KO increased BP (15-25 mm Hg) and worsened renal markers of injury, inflammation and fibrosis, GFR, UACR, and survival rates, as observed in control and, more pronouncedly, in ob/ob mice and independent of sex.
Deletion, but not heterozygosity, of eNOS raises blood pressure and aggravates nephropathy in BTBR ob/ob mice.
ob/ob 小鼠是一种瘦素缺乏型 2 型糖尿病模型，在 BTBR 背景下，模拟了糖尿病肾病 (DN) 的肾小球病理生理学。由于瘦素缺乏会降低血压 (BP)，而内皮型一氧化氮合酶 (eNOS) 也会降低血压并具有肾脏保护作用，因此我们试图通过在 BTBR ob/ob 小鼠中引入 eNOS 缺乏来开发一种更强大的 DN 模型。
六个实验组包括同窝出生的雄性和雌性 BTBR ob/ob 或野生型 ob（对照）以及野生型 (WT)、杂合子 (HET) 或 eNOS 敲除 (KO)。在 27-30 周龄的清醒小鼠中通过自动尾套测定收缩压 (SBP) 和肾小球滤过率 (GFR)（通过 FITC-顺式曲司汀血浆动力学），随后进行分子和组织学肾脏分析。
雄性和雌性 ob/ob WT 尽管血压略低于对照 WT，但出现了高血糖和更大的体重和肾脏重量、GFR、肾小球损伤和尿白蛋白与肌酐比值 (UACR)。这些影响与男性中肾小管损伤评分和肾脏中 NGAL 的 mRNA 表达升高有关，而女性 ob/ob WT 出人意料地与对照 WT 相比，肾脏中 KIM-1 和 COL1A1 的表达降低，表明存在性别差异。eNOS 的 HET 在对照或 ob/ob 中并不一致改变血压或肾脏结果。相比之下，eNOS KO 增加了血压 (15-25mmHg)，并恶化了肾损伤、炎症和纤维化的标志物、GFR、UACR 和生存率，在对照中观察到，在 ob/ob 中更为明显，并且独立于性别。
eNOS 的缺失而非杂合性增加了 BTBR ob/ob 小鼠的血压并加重了肾病。
