Kinetic study of glomerular epithelial cells associated with segmental glomerular sclerotic lesions with adhesion in spontaneously diabetic WBN/Kob rats

Background We previously found that glomerular epithelial cells play an important role in the formation of adhesive lesions. Glomerular sclerotic lesions develop after the inital adhesive lesions. Methods Two series of experiments were done with spontaneously diabetic WBN/Kob rats. These rats develop segmental glomerular sclerotic lesions with aging. The first series of experiments was intended to clarify the kinetics of glomerular cells on progressive glomerular damage in these rats. The second series of experiments was designed to study the relationship between proliferation (judged by % bromodeoxyuridine-positive cells) of glomerlar epithelial cells and sclerotic lesions with adhesions. Results In the first series, rats having increased proteinuria showed segmental glomerular sclerotic lesions with adhesions. At the same time, increased labeling indices of tuft cells and epithelial cells of Bowman's capsule were observed. In the second series, no significant increase in the labeling indices of tuft cells with sclerotic lesions was observed, compared to tuft cells without sclerotic lesions. In sclerotic lesions with adhesion, bromodeoxyurdine-positive cells were observed that were not distinguishable as podocytes or epithelial cells of Bowman's capsule. The highest labelling index was noted in the epithelial cells of Bowman's capsules with sclerosis. Conclusion This study shows that the proliferation of glomerular epithelial cells (mainly epithelial cells of Bowman's capsule) occurs in glomerular sclerotic lesions with adhesions.