Previous exposure to cigarette smoke aggravates experimental cyclosporine-induced nephrotoxicity.

BACKGROUND/AIMS: The effects of cigarette smoke (CS) on cyclosporine (CsA)-induced nephrotoxicity are poorly studied. This study aims to assess the effects of previous exposure to CS on CsA nephrotoxicity.

METHODS

Rats were either exposed to CS or sham (S) procedures for 10 min twice a day for 20 weeks. From the 16th to the 20th week, they received a low-salt diet. Beginning with the 17th week, they were given 2.5 mg/day CsA or vehicle (VH) for 3 weeks. The final groups were VH/CS, CsA/CS, VH/S, and CsA/S. On day 141, glomerular filtration rate (GFR), renal blood flow (RBF), renal vascular resistance (RVR), tubulointerstitial fibrosis, and CsA blood levels were measured and immunohistochemistry was analyzed for renal α-smooth muscle actin (SMA), nitrotyrosine, and vimentin.

RESULTS

CsA decrease in GFR was enhanced by CS exposure. CsA associated with CS induced higher periglomerular α-SMA and renal nitrotyrosine expression. CsA decreased RBF, but increased RVR, tubulointerstitial fibrosis, and α-SMA and renal vimentin expression. These changes and the CsA blood levels were not affected by CS exposure.

CONCLUSION

CS aggravated the CsA-induced impairment of GFR and CS associated with CsA caused the development of periglomerular structural lesions and oxidative stress in a rat model of CsA nephrotoxicity.