Abstract
Bupivacaine, a typical local anesthetic, induces neurotoxicity via reactive oxygen species regulation of apoptosis. High glucose could enhance bupivacaine-induced neurotoxicity through regulating oxidative stress, but the mechanism of it is not clear. Mitochondrial calcium uniporter (MCU), a key channel for regulating the mitochondrial Ca2+ (mCa2+) influx, is closely related to oxidative stress via disruption of mCa2+ homeostasis. Whether MCU is involved in high glucose-sensitized bupivacaine-induced neurotoxicity remains unknown. In this study, human neuroblastoma (SH-SY5Y) cells were cultured with high glucose and/or bupivacaine, and the data showed that high glucose enhanced bupivacaine-induced MCU expression elevation, mCa2+ accumulation, and oxidative damage. Next, Ru360, an inhibitor of MCU, was employed to pretreated SH-SY5Y cells, and the results showed that it could decrease high glucose and bupivacaine-induced mCa2+ accumulation, oxidative stress, and apoptosis. Further, with the knockdown of MCU with a specific small interfering RNA (siRNA) in SH-SY5Y cells, we found that it also could inhibit high glucose and bupivacaine-induced mCa2+ accumulation, oxidative stress, and apoptosis. We propose that downregulation expression or activity inhibition of the MCU channel might be useful for restoring the mitochondrial function and combating high glucose and bupivacaine-induced neurotoxicity. In conclusion, our study demonstrated the crucial role of MCU in high glucose-mediated enhancement of bupivacaine-induced neurotoxicity, suggesting the possible use of this channel as a target for curing bupivacaine-induced neurotoxicity in diabetic patients.
Highlights
About 113.9 million Chinese and over 300 million worldwide suffer from diabetes mellitus, and the number is expected to enlarge further in the future [1, 2]
Compared to the control group, cell viability was significantly inhibited in cells exposed to high glucose (10, 25, or 50 mM) (P < 0 05)
Our findings demonstrate that high glucose enhances bupivacaine-induced neurotoxicity via Mitochondrial calcium uniporter (MCU)-mediated oxidative stress
Summary
About 113.9 million Chinese and over 300 million worldwide suffer from diabetes mellitus, and the number is expected to enlarge further in the future [1, 2]. Patients with diabetic polyneuropathy receiving intrathecal anesthesia or analgesia are at increased risk of neurological dysfunction, but the mechanism remains unclear [5]. Previous studies have provided detailed evidence on local anesthetic-induced neurotoxicity triggered by oxidative stress [10]. Bupivacaine, one of the commonly used local anesthetics in clinics, induces cell apoptosis via reactive oxygen species (ROS). Studies have confirmed some key factors for synergism to regulate bupivacaineinduced ROS overproduction. It can decrease respiratory chain complex activity, uncouple oxidative phosphorylation, and inhibit ATP production which leads to mitochondrial membrane potential collapse [13]. ATP production dysfunction leads to adenosine monophosphate-activated protein kinase activation and aggravates ROS overproduction, leading to bupivacaine-induced apoptosis and neurotoxicity [14]. Oxidative Medicine and Cellular Longevity the mechanism responsible for the above phenomenon remains unknown
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