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.