[Production of reactive oxygen species and scavenger treatment in nephrotoxic nephritis]

Role of reactive oxygen species (ROS) was studied in accelerated nephrotoxic nephritis (NTN) in rats. In this experimental model, histological examination, and luminol amplified chemiluminescence (CL) assay of peripheral polymorphonuclear neutrophils (PMN), peritoneal macrophages (M phi), and isolated glomeruli were performed time-sequentially. Effect of ROS scavengers were also examined in this experiment. Daily dosages of bovine liver catalase and SOD were 550,000 and 1,000 units respectively. After nephrotoxic IgG injection, CL of glomeruli increased strikingly attaining peak at day 1, and remained high until the end of the experiment. This increase of CL may have reflected the release of ROS by glomerular cells and/or infiltrating cells stimulated in situ. In fact, peripheral PMN and peritoneal M phi showed no increase of CL after nephrotoxic IgG injection. Glomerular cells increased as early as 3 hours after induction of nephritis. Accumulation of PMN was noted for the first three days, whereas that of M phi became prominent after 4 days. Favourable effect was obtained in terms of proteinuria by administration of catalase, only when catalase was given at initial 3 days of nephritis. The data suggest that generation of ROS reflected by increase of CL in glomeruli of NTN rats is attributable to the PMN and M phi infiltrated in glomeruli as well as glomerular resident cells per se. It is also suggested that glomerular PMN increasing in the early phase of NTN plays a considerable role in glomerular injury.