Effects of newly synthesised platinum(ii) complexes on mitochondrial functions

Cisplatin- and dietary ascorbic acid-mediated changes in the mitochondria of Dalton's lymphoma-bearing mice

Cisplatin treatment caused a significant increase in the life span of ascites Dalton's lymphoma (DL) Tumor-bearing (TB) mice. However, as compared to cisplatin (CP) alone, combination treatment with ascorbic acid plus CP resulted in better therapeutic efficacy against murine DL. Cisplatin treatment of TB mice resulted in the appearance of thickened and irregular arrangement of mitochondrial cristae in the liver, kidney and DL tumor cells. Combination treatment of the hosts with ascorbic acid and CP lessened deformities in the mitochondria of liver and kidney, while in tumor cells, this increased the formation of vacuoles and disruption in mitochondrial cristae. Cisplatin treatment decreased the succinate dehydrogenase (SDH) activity in the mitochondria of kidney and DL cells and combination treatment caused further decrease in SDH activity in kidney and DL cells during 24-48 h of treatment. After CP treatment, the protein content in the mitochondria of these tissues decreased, and during combination treatment, it showed significant improvement. Mitochondrial lipid peroxidation (LPO) increased in these tissues after CP treatment. However, combination treatment significantly decreased mitochondrial LPO in liver and kidney but increased in DL cells. This increase in mitochondrial LPO in DL cells and decrease in liver and kidney could play an important role in the antitumor activity of combination treatment and at the same time reduce CP-induced toxicity in the host. However, further study may be desirable to explore some aspects of the mechanism(s) involved in these changes in mitochondria.

Differential effects of cisplatin on mouse hepatic and renal mitochondrial DNA

The objective of this study was to determine if the nephrotoxic effects induced by cisplatin were correlated to mitochondrial DNA damage. Comparisons were made with the liver since hepatotoxicity is rarely observed. Cisplatin doses of 10, 20 and 40 mg/kg were administered intraperitoneally to C57BL/6J mice. Mitochondrial DNA was isolated from both the hepatic and renal tissues and quantitated by hybridization with a specific mitochondrial probe. Cisplatin caused differential effects on mouse hepatic and renal mitochondrial DNA. The 10 and 20 mg/kg dose caused an elevation in mitochondrial DNA levels in the hepatic, but no increase in the renal tissue was observed. This is the first study demonstrating an organ specific effect of cisplatin at the DNA level.