Lidocaine Induce Neurotoxicity and Peripheral Nerve Injury in Trigeminal Nerve System

Objectives: Local anesthetics (LAs) are widely used in dentistry for their ability to block nerve impulses, particularly lidocaine. However, LAs can commonly cause neurotoxicity In vitro and In vivo. Our study investigated the neurotoxic effects of lidocaine and the occurrence of peripheral nerve injury when lidocaine is injected for local or regional anesthesia in the oro-facial area.

Methods: Sprague-Dawley rats were used in trigeminal ganglion (TG) neuron preparation and incubated with lidocaine. Cell death was assessed using a visual microscope. Nerve injury was detected by activating transcription Factor 3 (ATF3) expression in TG neurons after lidocaine injection into the trigeminal nerve endings in the infraorbital area.

Results: The rat TG neurons were killed by lidocaine after 24 hours of incubation. Cell death depends on the concentration of lidocaine, resulting in 39.83% cell death at 10 mM lidocaine, 75.20% at 20 mM lidocaine, and 89.90% at 50 mM (p<0.03), compared to 1.56% in saline. The cell membrane was damaged, and the nuclei showed signs of fragmentation in DAPI staining. Nerve injury was indicated by ATF3 immunoreactivity (IR) in the nuclei of TG neurons in the maxillary area of the TG in naïve (n=10), saline (n=50), 1% lidocaine (n=95), 2% lidocaine (n=319) (p<0.02), and 5% lidocaine (n=433) groups (p<0.01).

Conclusion: Lidocaine may induce neurotoxicity and nerve injury in vitro and in vivo at clinical concentrations or in cases of overdose.