EFFECT OF METHYLPREDNISOLONE ON TRANSFORMING GROWTH-FACTOR-BETA, INSULIN-LIKE GROWTH FACTOR-I, AND BASIC FIBROBLAST GROWTH-FACTOR GENE-EXPRESSION IN THE KIDNEYS OF NZB W F1-MICE/

The present study was carried out to determine whether transforming gr owth factor-beta, insulin-like growth factor-I and basic fibroblast gr owth factor mRNA levels were correlated with disease activity in NZB/W F1 mice, an animal model of systemic lupus erythematosus. Levels of m RNA for these three growth factors increased significantly as nephriti s progressed in these mice. At 48 weeks of age, transforming growth fa ctor-beta, insulin-like growth factor-I, and basic fibroblast growth f actor mRNA levels showed a 11- (p < 0.001), 10- (p < 0.001), and 8-fol d (p < 0.001) increase, respectively, in the renal cortex of NZB/W F1 mice when compared with NZW control mice. In NZW kidneys, these mRNA l evels showed little change throughout the study period. At 24 weeks of age, NZB/W F1 mice were divided in 2 groups that received either meth ylprednisolone or saline injections for 24 weeks. The development of h istological lesions and the increase in these growth factor mRNA level s in the kidneys of NZB/W F1 mice were both suppressed by methylpredni solone. These results indicate that the transforming growth factor-bet a, insulin-like growth factor and basic fibroblast growth factor may p lay a role in the progression of murine lupus nephritis and that methy lprednisolone may be an effective treatment at the transcription level of these growth factor genes for this type of nephritis.