Cisplatin-induced kidney injury in the rat: L-carnitine modulates the relationship between MMP-9 and TIMP-3.

Renal interstitial fibrosis is a major complication of cisplatin treatment, due to the increased accumulation of extracellular matrix (ECM) proteins whose remodeling is important for the development of normal tissues; indeed, its malfunction might play a role in the etiology of various diseases. Biopharmacological evaluations suggest that L-carnitine can prevent cardiac metabolic damage caused by doxorubicin, as well as can inhibit cisplatin-induced injury in the kidney and in the small intestine, without any interference with the drug's antitumoral properties. Since the glomerular basement membrane and the mesangial matrix constitute the ECM of the renal glomerulus, we examined the localization and expression of MMP-9 and TIMP-3 in normal rat kidney and the changes in their expression over a period of time by treatment with cisplatin, with and without L-carnitine. MMP-9 immunoreaction in cisplatin-treated rat kidney tissue suggests an involution of the basal membrane, an alteration of ECM components and low glomerular function, due to the increased thickness of the mesangium. Our results suggest that the matrix remodeling by MMP-9 and TIMP-3, in the later stages, can play an important role in the development of glomerular sclerosis and interstitial fibrosis after cisplatin treatment. It can also be postulated that L-carnitine protects from cisplatin injury, by modulating the relationship between MMP-9 and TIMP-3.