Direct effects of platelet-activating factor on glomerular capillary permeability.
Direct effects of platelet-activating factor on glomerular capillary permeability.
复制标题
血小板活化因子对肾小球毛细血管通透性的直接影响。
DOI：
10.1159/000174107
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发表时间：
1997
影响因子：
2.8
通讯作者：
Savin,VJ
中科院分区：
文献类型：
--
作者：
Sharma,R;Sharma,M;Li,JZ;McCarthy,ET;Savin,VJ
Platelet-activating factor (PAF) is an important mediator of injury in acute renal failure and glomerulonephritis. Intrarenal infusion of PAF reduces glomerular filtration rate and renal plasma flow and increases glomerular permselectivity via its renal hemodynamic and/or immunologic effects. Direct effects of PAF on glomerular capillary permeability are not known. We studied the direct effects of PAF on mesangial contraction (a measure of filtration area), glomerular capillary hydraulic conductivity (Lp) and capillary albumin permeability (Palbumin)· Glomeruli were isolated from Sprague-Dawley rats and incubated with or without various concentrations of PAF (10-9,10-7and 10-5M) for up to 5 h at 37⁰C. Mesangial contraction (percent change in glomerular volume) was assessed from the gradual decrease in volume of glomeruli during 20 min of incubation with PAF. Lpwas calculated from the rate of change in glomerular volume during the 0.1 s of capillary expansion in response to a transcapillary oncotic gradient. Palbuminwas calculated from a change in relative volume of glomeruli in response to an oncotic gradient. Mesangial contraction was maximal after 20 min of incubation and was concentration dependent (5.2+0.9, 7.9 ± 1.0 and 10.0+1.0%, respectively, with PAF 10-9,10-7and 10-5M). Incubation of glomeruli with PAF 10-7Mfor 60 min at 37°C caused a significant decrease in Lp(2.25 ± 0.30 vs. control 3.12 ± 0.28 µl·min-1•mm Hg-1cm-1, n= 5). Palbuminof glomeruli incubated with PAF was unchanged up to 2 h but increased significantly with the highest concentration of PAF (10-5M) after 3 h of incubation (0.60 ± 0.18, n = 15, vs. control 0.00 ± 0.08, n = 20), whereas lower concentrations of PAF (10-7or 10-9M) required at least 5 h of incubation with glomeruli to cause a significant increase in Palbumin(0.45 ± 0.09 and 0.48 ± 0.07, respectively, n = 15, vs. control 0.00 ± 0.08, n = 15). We conclude that PAF has multiple direct effects on glomerular functions, which are time dependent and may contribute to the altered capillary permeability in vivo.
