Platelets are not critical effector cells for the time course of murine passive crescentic glomerulonephritis

Abstract

Although platelets are well-known effector cells of inflammatory renal disease, clinical studies were not able to establish platelet inhibition as an effective therapy. Our previous studies using Vasodilator stimulated Phosphoprotein- and P2Y1-deficient mice suggested some early, but no long-term effects of platelets in passive crescentic glomerulonephritis. To define the role of platelets for this disease model, passive crescentic glomerulonephritis was induced in 72 C57Bl/6 mice by intraperitoneal injection of sheep anti-rabbit glomerular basement membrane antibody on 2 consecutive days. Platelets were depleted using anti-glycoprotein Ibα antibodies (p0p3/p0p4) every 4th day. Mice treated with equal amounts of sterile Phosphate buffered solution or rat-IgG served as controls. Blood, urine, and tissues were harvested on days 3 and 28. Renal tissue sections were evaluated after immunostaining using (semi)quantitative and computer-assisted image analysis. Compared to controls, efficient depletion was achieved as indicated by a markedly prolonged bleeding time and a more than 90% reduction in platelet counts (800/nl vs. 42/nl; P < 0.001). Functional (creatinine-clearance and proteinuria) parameters demonstrated no significant differences between the groups. Neither parameters of renal injury (glomerulosclerosis and fibrosis) nor glomerular/tubulointerstitial matrix expansion (by collagen IV staining), glomerular capillary rarefaction (lectin staining), and the glomerular/tubulointerstitial proliferative response (proliferating cell nuclear antigen) demonstrated any differences between platelet-depleted mice and PBS- or rat-IgG-treated nephritic mice at any time point. Despite effective platelet inhibition/depletion, neither the short- nor long-term course of passive crescentic nephrotoxic nephritis was affected. These data indicate that platelets play a minor role during the time course of this disease model in the mouse.

• Platelets
• inflammatory renal disease
• crescentic glomerulonephritis

Acknowledgements

The skilled technical assistance of S. Weber, A. Braun, S. Cabric, and M. Klewer is gratefully acknowledged. We gratefully acknowledge the kind gift of anti-GPIbα IgG antibodies and the subsequent discussion of results by Prof. B. Nieswandt, Virchow-Center Wuerzburg, Germany.

Declaration of interests: This work was supported by grants to K. Amann (SFB 423 TP Z2) and C. Hugo (IZKF Erlangen TP A12 and SFB 423 TP B6). Authors declare that they do not have any relationships or financial interests with companies related to the findings of this work.