Recent studies have demonstrated that an inflammatory mechanism contributes to the pathogenesis of diabetic nephropathy (DN). It is also known that colchicine (Col) can prevent various renal injuries via its anti-inflammatory action. However, the effect of colchicine on DN has never been explored. This study was undertaken to elucidate the effect of colchicine on inflammation and extracellular matrix accumulation in DN. In vivo, 64 rats were injected with diluent (C; n = 32) or streptozotocin intraperitoneally (DM, n = 32). Sixteen rats from each group were treated with Col. In vitro, rat mesangial cells and NRK-52E cells were cultured in media with 5.6 mM glucose (NG) or 30 mM glucose (HG) with or without 10(-8) M Col. Monocyte chemotactic protein-1 (MCP-1) mRNA expression was determined by real-time PCR (RT-PCR), and the levels of MCP-1 in renal tissue and culture media were measured by ELISA. RT-PCR and Western blotting were also performed for intercellular adhesion molecule-1 (ICAM-1) and fibronectin (FN) mRNA and protein expression, respectively, and immunohistochemical staining (IHC) for ICAM-1, FN, and ED-1 with renal tissue. Twenty-four-hour urinary albumin excretion at 6 wk and 3 mo were significantly higher in DM compared with C rats (P < 0.05), and colchicine treatment significantly reduced albuminuria in DM rats (P < 0.05). Col significantly inhibited the increase in MCP-1 mRNA expression and protein levels under diabetic conditions both in vivo and in vitro. ICAM-1 and FN expression showed a similar pattern to the expression of MCP-1. IHC revealed that the number of ED-1(+) cells were significantly higher in DM compared with C kidney (P < 0.005), and this increase was significantly attenuated by Col treatment (P < 0.01). In conclusion, Col prevents not only inflammatory cell infiltration via inhibition of enhanced MCP-1 and ICAM-1 expression but also ECM accumulation in DN. These findings provide a new perspective on the renoprotective effects of Col in DN.

Diabetic nephropathy (DN) is clinically characterized by proteinuria. Many studies tried to demonstrate a relationship between proteinuria and changes in nephrin in various forms of glomerular diseases including DN, but the results are not consistent. Glomerular hypertrophy occurs in DN, yet hypertrophy does not develop in all glomeruli concurrently. For investigation of the differences in nephrin expression according to glomerular size, glomeruli were isolated from 10 control and 10 streptozotocin-induced diabetic rats at 6 wk after the induction of diabetes by a sieving technique using sieves with pore sizes of 250, 150, 125, and 75 m. Glomeruli then were classified into large glomeruli (LG; on the 125-m sieve) and small glomeruli (SG; on the 75-m sieve) groups. Glomerular volumes were determined using an image analyzer, and mRNA and protein expression was determined by real-time PCR and Western blot, respectively. The mean volumes of diabetic LG (1.51 Ϯ 0.06 ϫ 10 6 m 3 ) and control LG (1.37 Ϯ 0.05 ϫ 10 6 m 3 ) were significantly higher than those of diabetic SG (0.94 Ϯ 0.03 ϫ 10 6 m 3 ) and control SG (0.87 Ϯ 0.03 ϫ 10 6 m 3 ; P Ͻ 0.01). Nephrin mRNA expression was significantly reduced in the diabetic LG group compared with the diabetic SG and control glomeruli groups (P Ͻ 0.05). In contrast, nephrin mRNA expression was significantly higher in the diabetic SG group compared with the diabetic LG and control glomeruli groups (P Ͻ 0.05). Even after correction for 18s rRNA and Wilms' tumor-1 mRNA expression, the differences in nephrin mRNA expression remained significant. The expression of nephrin protein showed a similar pattern to the mRNA expression. In conclusion, these data suggest that the nephrin gene is differentially expressed according to glomerular size. Furthermore, more hypertrophied glomeruli with lesser nephrin expression may be responsible for albuminuria in the early stage of DN.

Besides roles in nucleus mediating the condensation of DNA into chromatin, the involvement of histones in autoimmune diseases, hormone regulation, and killing leukemia cells has been reported. In order to investigate the functions of histones on an autoimmune disease, histone H1 was injected into collagen-induced arthritis (CIA) mice. A dramatic suppression of CIA by histone H1 was observed at a dose of 1 mg/kg bodyweight of mouse. In addition, the increased level of anti-inflammatory cytokine IL-10 was detected in cultured splenocytes from the mouse treated with histone H1. These findings suggest that histone H1 suppresses the collagen-induced arthritis, possibly by increasing the level of IL-10 production.