Hansell P, Göransson V, Odlind C, Gerdin B, Hällgren R
Department of Physiology, University of Uppsala, Uppsala, Sweden.
Kidney Int. 2000 Nov;58(5):2061-8. doi: 10.1111/j.1523-1755.2000.00378.x.
Growing evidence suggests that the interstitial hyaluronan (HA) content is a determinant of the fluid exchange barrier in tissues through its high resistance to water flow. This study addressed the possible involvement of renal papillary HA in water balance regulation.
In anesthetized rats during different states of renal water handling (euvolemia, water diuresis, antidiuresis), in desert rodents, and in Brattleboro rats (diabetes insipidus) with a hereditary difference in water handling, regional renal HA and water contents were measured.
The intrarenal HA distribution is heterogeneous, with 100 times larger amounts in the papilla than in the cortex. Compared with control rats, two hours of water diuresis increased the papillary HA content by 48% and that in the outer medulla by 52%, leaving the cortex unaffected. After 24 hours of water deprivation, papillary HA was decreased by 17%, while outer medullary HA remained unchanged. In gerbils, papillary and outer medullary HA contents were only 25 and 13%, respectively, of those in normal rats, while the cortical content was similar. In Brattleboro rats, the outer medullary HA content was significantly higher (285%) than in the normal rat, while the papillary content was similar. Generally, papillary HA was positively correlated to water content but was inversely related to urine osmolality.
The amount of renal papillary HA changes in response to water balance of the organism. When excess water needs to be excreted, increased papillary interstitial HA could antagonize water reabsorption. The opposite occurs during water conservation. HA may play a role in renal water handling by affecting physicochemical characteristics of the papillary interstitial matrix and influencing the interstitial hydrostatic pressure, thereby determining interstitial water diffusion.
越来越多的证据表明，组织间透明质酸（HA）含量因其对水流的高阻力而成为组织中液体交换屏障的一个决定因素。本研究探讨了肾乳头HA在水平衡调节中的可能作用。
在麻醉大鼠处于不同肾脏水代谢状态（等容、水利尿、抗利尿）时，以及在沙漠啮齿动物和遗传性水代谢存在差异的布拉特洛维大鼠（尿崩症）中，测量肾脏不同区域的HA和水含量。
肾脏内HA分布不均一，乳头中的含量比皮质中的多100倍。与对照大鼠相比，两小时的水利尿使乳头HA含量增加48%，外髓质HA含量增加52%，而皮质HA含量未受影响。禁水24小时后，乳头HA含量降低17%，而外髓质HA含量保持不变。在沙鼠中，乳头和外髓质HA含量分别仅为正常大鼠的25%和13%，而皮质含量相似。在布拉特洛维大鼠中，外髓质HA含量显著高于正常大鼠（285%），而乳头HA含量相似。总体而言，乳头HA与水含量呈正相关，但与尿渗透压呈负相关。
肾乳头HA量随机体水平衡变化而改变。当需要排出多余水分时，乳头组织间HA增加可对抗水重吸收。保水时则相反。HA可能通过影响乳头组织间基质的物理化学特性和影响组织间静水压，从而决定组织间水扩散，在肾脏水代谢中发挥作用。
