Ropivacaine impairs mitochondrial biogenesis by reducing PGC-1α.

Ropivacaine is one of the commonly used local anesthetics in medical and dental care. However, preclinical and observational studies indicate that ropivacaine could have substantial side effects including neurotoxicity, which has raised concern regarding the safety of this drug. In the present study, we investigated the effects of clinically relevant doses of ropivacaine on mitochondrial biogenesis and function in neuronal cells. Our data indicate that exposure to ropivacaine leads to reduced expression of the major mitochondrial regulator PGC-1α and its downstream transcription factors NRF1 and TFAM. Ropivacaine treatment induces impairment of mitochondrial biogenesis by reducing mitochondrial mass, the ratio of mtDNA to nDNA (mtDNA/nDNA), cytochrome C oxidase activity, and COX-1 expression. Additionally, treatment with ropivacaine causes "loss of mitochondrial function" by impairing the mitochondrial respiratory rate and ATP production. Mechanistically, the reduction of PGC-1α caused by ropivacaine exposure requires inactivation of CREB, while re-introduction of PGC-1α completely rescues ropivacaine-induced mitochondrial abnormalities. In summary, our results provide supporting evidence that mitochondrial impairment is a key event in ropivacaine-mediated neurotoxicity, and the reduction of PGC-1α and its downstream signals are likely the molecular mechanism behind its cellular toxicity.