Effect of methylprednisolone and "pulse" therapy with methylprednisolone sodium succinate on autologous immune complex nephritis in rats.

Autologous immune complex (AIC) nephritis was induced in rats with a single foot-pad injection of renal tubular epithelial antigen suspended in complete Freund's adjuvant. It was suggested by gel filtration of serum on Sephadex G-200 column that increase in the concentration of macroglobulins was the first alteration reflected on the serum proteins after immunization; the concentration of macroglobulins increased while the concentrations of albumin and gamma-globulin still remained in the normal range. The effect of 6 alpha-methylprednisolone sodium succinate (MP-S), 6 alpha-methylprednisolone (MP) and cyclophosphamide on the AIC nephritis in rats was studied. "Pulse" therapy, that is, an intraperitoneal administration of a large dose (26.5 mg/kg) of MP-S for 3 successive days a week and followed by an intermission for 4 days a week was started from the week of immunization with renal tubular epithelial antigen and continued for 8 weeks, resulting in the retardation of the AIC nephritis induction associated with a partial suppression of the development of proteinuria. Treatment with MP (4 mg/kg) or cyclophosphamide (10 mg/kg) every other day from the week of immunization for 8 weeks partially retarded or completely suppressed the AIC nephritis induction, respectively. On the other hand, the MP-S "pulse" therapy and the MP treatment of rats suffering from the already established AIC nephritis resulted in no apparent improvement of the disease.