Effect of interleukin-8 on glomerular sulfated compounds and albuminuria

To evaluate the effect of interleukin-8 (IL8) on glomerular basement membrane (GEM) sulfated compounds and albuminuria, we infused IL8 in 1% bovine serum albumin (BSA) for 5 days into the left renal artery of Holtzman male rats at the rate of 10 mu l/h using an osmotic pump. Control rats received 1% BSA. A significant increase in urinary albumin/creatinine ratio was seen on the last day of as infusion (0.38 +/- 0.11, mean +/- SEM) when compared with albumin/creatinine ratio prior to infusion (0.19 +/- 0.04, P = 0.04). No significant differences in urinary albumin excretion prior to and after infusion of 1% BSA were observed. On the last day of infusion, rats were injected with (35)sulfate (1.0 mCi/200 g body weight) intraperitoneally and killed after 8 h. Glomeruli were isolated and GEM obtained. After 5 days of IL8 administration, there was a significant increase in (35)sulfate uptake by GEM of the infused kidney (76 + 10 cpm/dry glomerular weight, mean +/- SEM) compared with the uptake seen in the contralateral kidney (53 +/- 9, P = 0.05). The in vivo infusion of IL8 increased the (35)sulfate uptake by GEM and augmented the urinary albumin/creatinine ratio, suggesting that IL8 may induce albuminuria by altering the metabolism of the GEM sulfated compounds. This hypothesis needs to be confirmed by studies on glomerular charge selectivity and GEM anionic sites during the course of the infusion. Moreover, the persistence of the effect needs to be evaluated by prolonging the infusion for more than 5 days.