Neurotoxicity Induced by Bupivacaine via T-Type Calcium Channels in SH-SY5Y Cells

Xianjie Wen,Chenxiang Yang,Shiyuan Xu,Hanbing Wang,Hua Liang,Quinguo Zhang,Hongzhen Liu,Valentin Ceña

doi:10.1371/journal.pone.0062942

Abstract

There is concern regarding neurotoxicity induced by the use of local anesthetics. A previous study showed that an overload of intracellular calcium is involved in the neurotoxic effect of some anesthetics. T-type calcium channels, which lower the threshold of action potentials, can regulate the influx of calcium ions. We hypothesized that T-type calcium channels are involved in bupivacaine-induced neurotoxicity. In this study, we first investigated the effects of different concentrations of bupivacaine on SH-SY5Y cell viability, and established a cell injury model with 1 mM bupivacaine. The cell viability of SH-SY5Y cells was measured following treatment with 1 mM bupivacaine and/or different dosages (10, 50, or 100 µM) of NNC 55-0396 dihydrochloride, an antagonist of T-type calcium channels for 24 h. In addition, we monitored the release of lactate dehydrogenase, cytosolic Ca2+ ([Ca2+]i), cell apoptosis and caspase-3 expression. SH-SY5Y cells pretreated with different dosages (10, 50, or 100 µM) of NNC 55-0396 dihydrochloride improved cell viability, reduced lactate dehydrogenase release, inhibited apoptosis, and reduced caspase-3 expression following bupivacaine exposure. However, the protective effect of NNC 55-0396 dihydrochloride plateaued. Overall, our results suggest that T-type calcium channels may be involved in bupivacaine neurotoxicity. However, identification of the specific subtype of T calcium channels involved requires further investigation.

Highlights

Regional anesthetics have been used widely in clinical settings and as postoperative analgesics, because of their reduced systemic effects [1,2]
One multicenter study found that the incidence of transient neurological syndrome (TNS) was approximately 8.1%, which resulted in pain or sensory abnormalities in the lower back, buttocks, or lower extremities, with symptoms beginning after spinal anesthesia and lasting for hours to 4 days [5]
Cell Viability Viability of SH-SY5Y cells dose-dependently decreased with increasing concentrations of bupivacaine

Summary

Introduction

Regional anesthetics have been used widely in clinical settings and as postoperative analgesics, because of their reduced systemic effects [1,2]. Local anesthetics may cause neurotoxicity, such as transient neurological syndrome (TNS), and cauda equina syndrome, which has raised concerns about their use [3,4]. Local anesthetics can cause cell apoptosis, induce the release of reactive oxygen species and lactate dehydrogenase (LDH) [9,10]. Previous studies indicated that intracellular calcium overload is involved in local anesthetic-induced neurotoxicity [12,13]. Extracellular calcium influx and intracellular calcium store release are the most important factors for local anesthetic-induced calcium overload. An influx of extracellular calcium can induce calcium-dependent release of intracellular calcium stores [14,15]

Methods

Results

Conclusion