The effect of ropivacaine hydrochloride on Fas/Fasl-meditated apoptosis in the rat spinal cord: an in vivo experiment.

Ropivacaine hydrochloride (RH) has potential neurotoxicity, although the exact mechanism is unclear. In this study, the expression of Factor associated suicide receptor (Fas) and its ligand (FasL) in the spinal cord cells was detected in rats receiving repeated intrathecal injection of RH. The paw mechanical withdraw threshold (MWT) was measured before and 3 days after intrathecal cannulation and 24 hours after intrathecal injection. Rats received intrathecal injection of 0.5%, 1%, 2% RH at 0.12 ml/kg or saline of equal volume alone. Intrathecal injection was done 8 times with an interval of 1.5 hour in 12 hour. The spinal cord was collected for pathological examination; TUNEL staining was used to assess the apoptosis in the spinal cord and the expression of Fas, FasL, caspase-3, and caspase-8 was detected. Results showed that intrathecal injection of 1% and 2% RH significantly increased the MWT (P<0.05) and more vacuoles or edema was observed in the spinal cord after RH treatment. The apoptosis rates and expression of Fas, FasL, caspase-3, and caspase-8 increased significantly in the RH groups (P<0.05). Therefore, repeated intrathecal injection of RH may cause damage to the spinal cord and induce apoptosis in the spinal cord via up-regulation of Fas/FasL expression.

盐酸罗哌卡因（Ropivacaine hydrochloride, RH）具有潜在神经毒性，但其具体作用机制尚未明确。本研究对反复接受鞘内注射（intrathecal injection）RH的大鼠，检测其脊髓细胞中死亡因子受体（Factor associated suicide receptor, Fas）及其配体（FasL）的表达水平。分别在鞘内置管前、鞘内置管后3天以及鞘内注射后24小时，测定大鼠后肢机械撤足阈值（paw mechanical withdraw threshold, MWT）。实验大鼠分为四组：分别以0.12 ml/kg的剂量鞘内注射0.5%、1%、2%浓度的RH，或注射等体积生理盐水。鞘内注射共进行8次，每次间隔1.5小时，总时长为12小时。采集各组大鼠脊髓组织进行病理学检查；采用TUNEL染色（TUNEL staining）评估脊髓细胞凋亡情况，并检测Fas、FasL、半胱氨酸天冬氨酸蛋白酶3（caspase-3）及半胱氨酸天冬氨酸蛋白酶8（caspase-8）的表达水平。结果显示，鞘内注射1%及2%浓度的RH可显著升高大鼠MWT（P<0.05），且经RH处理后，大鼠脊髓组织可见更多空泡及水肿现象。RH给药各组的脊髓细胞凋亡率，以及Fas、FasL、caspase-3、caspase-8的表达水平均显著升高（P<0.05）。综上，反复鞘内注射RH可能造成脊髓损伤，并通过上调Fas/FasL通路的表达诱导脊髓细胞凋亡。