Ascorbic Acid Promotes Recovery of Cellular Functions Following Toxicant-Induced Injury

Protein Kinase C-α and ERK1/2 Mediate Mitochondrial Dysfunction, Decreases in Active Na+ Transport, and Cisplatin-induced Apoptosis in Renal Cells

“…Measurement of Na ϩ /K ϩ -ATPase Activity-RPTC lysates were prepared as described previously (37). Briefly, 1.0 mg of RPTC protein was added to 0.1 ml of 25 mM imidazole buffer (pH 7.0) containing 0.065% SDS, 1% bovine serum albumin, and a phosphatase inhibitor mixture.…”

“…Following incubation for 10 min at 22°C, 0.6 ml of 0.3% bovine serum albumin in 25 mM imidazole buffer was added to lower the SDS concentration and aliquots were used for measurement of Na ϩ /K ϩ -ATPase activity. Na ϩ /K ϩ -ATPase activity was determined in cellular lysates by measuring the difference between total ATPase activity and ouabaininsensitive ATPase activity as described previously (37).…”

Protein Kinase C Mediates Repair of Mitochondrial and Transport Functions after Toxicant-Induced Injury in Renal Cells

“…RPTC monolayers were washed with 37°C culture medium and gently detached from the dishes with a rubber policeman, suspended in warm (37°C) culture medium and transferred to the oxygen consumption (QO 2 ) measurement chamber. QO 2 was measured polarographically in RPTCs suspended in the culture medium using Clark type electrode as described previously (Nowak and Schnellmann, 1996;Nowak et al, 1998Nowak et al, , 1999Nowak et al, , 2000. Basal QO 2 was used as a marker of entire mitochondrial function.…”

“…However, the repair of RPTC functions does not occur in sublethally injured RPTCs after DCVC exposure (Nowak et al, 1999). DCVC also decreases synthesis of extracellular matrix proteins of the RPTC basement membrane, including collagen IV, and disrupts localization of collagen binding integrins (Nowak et al, 2000;). Interestingly, epidermal growth factor and pharmacological concentrations of ascorbic acid promote the repair of mitochondrial function and active Na ϩ transport in DCVC-injured RPTCs (Nowak et al, 1999(Nowak et al, , 2000.…”

“…DCVC also decreases synthesis of extracellular matrix proteins of the RPTC basement membrane, including collagen IV, and disrupts localization of collagen binding integrins (Nowak et al, 2000;). Interestingly, epidermal growth factor and pharmacological concentrations of ascorbic acid promote the repair of mitochondrial function and active Na ϩ transport in DCVC-injured RPTCs (Nowak et al, 1999(Nowak et al, , 2000. The promotion of RPTC repair by ascorbic acid is mediated, in part, by collagen IV and is associated with the relocalization of collagen-binding integrins to the basement membrane .…”