Protective Effects of Bupivacaine against Kainic Acid-Induced Seizure and Neuronal Cell Death in the Rat Hippocampus

Abstract

The excessive release of glutamate is a critical element in the neuropathology of epilepsy, and bupivacaine, a local anesthetic agent, has been shown to inhibit the release of glutamate in rat cerebrocortical nerve terminals. This study investigated whether bupivacaine produces antiseizure and antiexcitotoxic effects using a kainic acid (KA) rat model, an animal model used for temporal lobe epilepsy, and excitotoxic neurodegeneration experiments. The results showed that administering bupivacaine (0.4 mg/kg or 2 mg/kg) intraperitoneally to rats 30 min before intraperitoneal injection of KA (15 mg/kg) increased seizure latency and reduced the seizure score. In addition, bupivacaine attenuated KA-induced hippocampal neuronal cell death, and this protective effect was accompanied by the inhibition of microglial activation and production of proinflammatory cytokines such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-α in the hippocampus. Moreover, bupivacaine shortened the latency of escaping onto the platform in the Morris water maze learning performance test. Collectively, these data suggest that bupivacaine has therapeutic potential for treating epilepsy.

Ropivacaine Protects against Memory Impairment and Hippocampal Damage in a Rat Neurodegeneration Model

“…Three days after KA treatment, the Morris water maze was used to measure the spatial learning and memory performance of rats. All experimental procedures were conducted as described previously [12]. A circular pool 200 cm in diameter and 50 cm height was used to perform the Morris water maze test.…”

“…These sliced sections were then incubated in a 1% solution of neutral red (Sigma-Aldrich, St. Louis, MO, USA) for 1 min to detect cell viability. Fluoro-Jade B staining was conducted, and the positive cells in the CA3 region were counted as described in a previous study [12] and 10-µm-thick brain sections were incubated 15 min with potassium permanganate (0.06%) and changed to a Fluoro-Jade B (0.001%) solution (Millipore, Temecula, CA, USA) for 30 min. Results were presented as the number of labelled cells per 0.1 mm 2 ± SEM.…”

“…Fluorescence microscopy was used to observe the apoptosis of neuronal cells. TUNEL labelled cells were counted in the hippocampal CA3 region as described in a previous study [12].…”

“…The sections were mounted and air-dried overnight on glass slides, and cover slipped with aqueous based mounting medium (Fluoromount TM Aqueous Mounting Medium, SigmaAldrich, St. Louis, MO, USA) after washing with PBS. KA-induced caspase-3-positive cells in the hippocampal CA3 region were quantified as described in a previous study [12].…”

“…Three different time points were chosen based on previous reports [12,14,15]. Following KA treatment, the rats were decapitated at 0.5 h, 4 h, and 3 days and the hippocampi were rapidly dissected and collected, respectively.…”