The effects of nucleoside/nucleotide and non-nucleoside reverse transcriptase inhibitors combination therapy on mitochondrial bioenergetics, reactive oxygen species generation, and uncoupling protein 2 expression in mouse hepatocytes

Abstract

Considerable scientific research has been directed to study the toxic effect of the different classes of anti-retroviral drugs on mitochondria. In a previous study done on mitochondrial hepatocytes, Lopimune a protease inhibitor, was proved to lead to mitochondrial damage, increased reactive oxygen species (ROS) production, and uncoupling protein 2 (UCP2) expression which, through a negative feedback mechanism, decreased ROS production to basal level. The focus of the present study was to examine whether nucleoside/nucleotide and non-nucleoside reverse transcriptase inhibitors, Duovir and Viraday, led to mitochondrial toxicity. Mitochondria were extracted from mouse liver through differential centrifugations and hepatocytes were isolated by the collagenase perfusion procedure. Rank Brothers oxygen electrode was used to measure mitochondrial respiration, 2, 7-dichlorofluorescin diacetate probe monitored ROS generation using flow cytometry, and western blot was used to detect UCP2 protein expression. The results indicated that mitochondria isolated from mice treated with either Duovir or Viraday had no significant effect on respiration states 2, 3, 4, FCCP and on the respiratory control ratio as compared to control mitochondria. This implicated that both drugs did not affect mitochondrial efficiency and ATP production. UCP2 protein was not detected in control and treated mitochondria, indicating that Duovir and Viraday did not induce mitochondrial proton leak. In addition, no significant variation in ROS production was detected between control and treated hepatocytes. In conclusion, the results indicated that some types of nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs) did not lead to mitochondrial toxicity and functioned through a different mechanism as compared to other anti-retroviral drugs such as Lopimune. Further investigations are required to identify the mechanism of action of antiretroviral drugs on mitochondrial bioenergetics.