IN-SITU HYBRIDIZATION OF INTERLEUKIN-6 IN DIABETIC NEPHROPATHY

Increased mesangial expansion is one of the most characteristic histol ogical changes in diabetic nephropathy (DN), Although the pathogenesis of DN remains unclear, recent studies associate interleukin (IL) 6 wi th mesangial proliferative glomerulonephritis. To elucidate the expres sion and localization of IL-6 mRNA in renal tissues of patients with D N, a high-resolution in situ hybridization using digoxigenin-labeled o ligonucleotide was performed, Patients were divided into three groups based on light microscopy findings: mild (group 1), moderate (group 2) , and severe (group 3) mesangial expansion, The relationship between t he expression of IL-6 mRNA and the degree of glomerular mesangial expa nsion in DN was examined, Individual cells positive for IL-6 mRNA were observed in glomeruli. These cells were mesangial cells, glomerular e pithelial cells, and Bowman's capsule, The signal intensity was strong est in tissues from group 2 but was weak in those from groups 1 and 3. Most cells in the area of mesangial proliferation were strongly stain ed for IL-6 mRNA, and few positive cells were found in the Kimmelstiel -Wilson nodular lesion, In the interstitium, some tubules, particularl y atrophic tubules, and some infiltrating cells were positively staine d for IL-6 mRNA, The interstitial expression of IL-6 mRNA correlated s ignificantly with the degree of interstitial injury and was remarkable in tissues from groups 2 and 3, We conclude that IL-6 mRNA is express ed by glomerular resident cells and interstitial cells in the renal ti ssue of patients with DN and that its expression may be associated wit h mesangial proliferation and may be involved in the tissue injury of DN.