Tomoda F, Takata M, Kinuno H, Tomita S, Yasumoto K, Inoue H
Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Toyama, Japan.
Hypertension. 2000 Jul;36(1):68-72. doi: 10.1161/01.hyp.36.1.68.
In 10- to 12-week-old Dahl salt-sensitive (DS) and salt-resistant (DR) rats fed a 0.3% salt diet (n=10 in each group), flow-pressure and pressure-glomerular filtration rate (F-P and P-GFR, respectively) relationships were established for maximally vasodilated perfused kidneys. From these relationships, 3 indices of vascular structural properties were estimated: slope of F-P (minimal renal vascular resistance reflecting overall luminal dimensions of preglomerular and postglomerular vasculature), slope of P-GFR (glomerular filtration capability against pressure), and threshold pressure for beginning filtration at P-GFR (preglomerular-to-postglomerular vascular resistance ratio). Thereafter, maximal renal vascular resistance was determined to assess wall-to-lumen ratios of the resistance vessels in half of each group. In the remainder, the kidneys were perfusion-fixed for histological analysis. Mean arterial pressure did not differ between the DS and DR rats. There were no significant differences in the slopes of F-P between the 2 groups. In contrast, the slope of P-GFR was significantly lower (33%) in DS rats than in DR rats, although the DS kidneys began filtering at a threshold pressure similar to that of the DR kidneys. Thus, in DS rats, there were no abnormalities in luminal dimensions at preglomerular and postglomerular vascular segments, but the kidney filtration capacity decreased at any given increase in pressure. Maximal vascular resistance was greater in DS than in DR rats, a finding compatible with the histological appearance, which showed vascular hypertrophy with little, if any, vascular narrowing in the interlobular arteries of DS rats. In conclusion, hypertrophic remodeling without vascular narrowing at preglomerular resistance vessels and structural defects in filtering at the glomeruli could occur in prehypertensive DS rats.
在喂食0.3%盐饮食的10至12周龄达尔盐敏感（DS）和盐抵抗（DR）大鼠（每组n = 10）中，建立了最大血管舒张灌注肾脏的血流压力与压力 - 肾小球滤过率（分别为F - P和P - GFR）关系。根据这些关系，估计了3个血管结构特性指标：F - P斜率（反映肾小球前和肾小球后血管总体管腔尺寸的最小肾血管阻力）、P - GFR斜率（肾小球滤过能力与压力的关系）以及P - GFR开始滤过时的阈值压力（肾小球前与肾小球后血管阻力比）。此后，测定每组一半大鼠的最大肾血管阻力以评估阻力血管的壁腔比。其余大鼠的肾脏进行灌注固定以进行组织学分析。DS和DR大鼠的平均动脉压无差异。两组之间F - P斜率无显著差异。相比之下，DS大鼠的P - GFR斜率显著低于DR大鼠（33%），尽管DS肾脏开始滤过的阈值压力与DR肾脏相似。因此，在DS大鼠中，肾小球前和肾小球后血管段的管腔尺寸无异常，但在任何给定的压力升高时肾脏滤过能力下降。DS大鼠的最大血管阻力大于DR大鼠，这一发现与组织学表现相符，即DS大鼠的小叶间动脉显示血管肥大且几乎没有血管狭窄。总之，高血压前期DS大鼠可能在肾小球前阻力血管处发生无血管狭窄的肥厚性重塑以及肾小球滤过的结构缺陷。
