Rohn D A, Stewart R H, Elk J R, Laine G A, Drake R E
Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, USA.
Lymphology. 1996 Jun;29(2):67-75.
The renal lymphatic system plays an important role in removing excess fluid from the kidneys. Unfortunately, the factors influencing lymphatic flow are difficult to measure. We used a simple model to represent renal lymphatics as a single pressure source (PL) pushing lymph through a single resistance (RL). In anesthetized dogs, we cannulated renal lymphatics and measured lymph flow rate (QL) as we varied pressure (PO) at the outflow end of the lymphatics. There was no significant change in QL as we increased PO from -5 to 0 cm H2O. In other words, there was a plateau in the QL vs. PO relationship. At higher PO's, QL decreased linearly with increases in PO. From this linear relationship, we calculated RL as -delta PO/ delta QL and we took PL as the PO at which QL = 0 microliter/min. At baseline, RL = 0.34 +/- 0.14 (SD) cm H2O.min/microliter and PL = 8.2 +/- 4.4 cm H2O. When we increased renal venous pressure (PV) from baseline (3.5 +/- 3.0 cm H2O), the plateau in the QL vs. PO relationship extended to higher PO's, RL decreased, and PL increased. Renal interstitial fluid volume and interstitial pressure increased following elevation of PV. The extension of the QL vs. PO plateau with increasing PV suggests that renal interstitial pressure may partially collapse intrarenal collecting lymphatics which may compromise lymph flow.
肾淋巴系统在清除肾脏多余液体方面发挥着重要作用。不幸的是，影响淋巴液流动的因素难以测量。我们使用了一个简单模型，将肾淋巴管表示为一个单一压力源（PL），该压力源推动淋巴液通过单一阻力（RL）。在麻醉的狗身上，我们将肾淋巴管插管，并在改变淋巴管流出端压力（PO）时测量淋巴液流速（QL）。当我们将PO从-5 cm H₂O增加到0 cm H₂O时，QL没有显著变化。换句话说，QL与PO的关系存在一个平台期。在更高的PO值时，QL随PO的增加呈线性下降。根据这种线性关系，我们计算RL为-ΔPO/ΔQL，并将PL视为QL = 0微升/分钟时的PO值。在基线时，RL = 0.34 ± 0.14（标准差）cm H₂O·分钟/微升，PL = 8.2 ± 4.4 cm H₂O。当我们将肾静脉压力（PV）从基线值（3.5 ± 3.0 cm H₂O）升高时，QL与PO关系的平台期扩展到更高的PO值，RL降低，PL升高。PV升高后，肾间质液体积和间质压力增加。随着PV升高，QL与PO平台期的扩展表明，肾间质压力可能会使肾内集合淋巴管部分塌陷，这可能会损害淋巴液流动。
