KIDNEY DYSFUNCTION IN THE ARTHRITIC RAT

Kidney function and histopathology were investigated in the adjuvant-i nduced arthritic rat. Rats injected with Mycobacterium butyricum exhib ited symptoms of arthritis (i.e. paw edema and loss of body weight) by day 9 which worsened and included systemic manifestations of the dise ase on days 16 and 30. Definite signs of kidney dysfunction were obser ved by day 16 which included elevated urine output and plasma creatini ne values and decreased creatinine clearance. By day 30, these paramet ers were similar to the values obtained from normal rats; however, kid ney weights from arthritic rats were still greater than those from nor mal rats. Histopathologic abnormalities observed in the kidneys of art hritic rats on day 30 included tubular lesions consisting of focal bas ophilia, edema, granular deposits and basement membrane thickening. Ch anges in the glomerulus included granular deposits with focal glomerul opathy. These findings are the first to clearly demonstrate kidney dys function and histopathologic alterations associated with the early exp ression of the adjuvant-induced disease process in the rat. Our observ ations in the rat suggest that renal dysfunction in man can be mediate d by the inflammatory disease process and is not solely a drug treatme nt-induced side effect.