Tanshinone IIA attenuates nerve transection injury associated with nerve regeneration promotion in rats

Tanshinone IIA (Tan IIA) is the major pharmacological constituent of Salvia miltiorrhiza Bunge (Danshen) for the therapeutic purpose of preventing ischemic injury and treating cerebrovascular disease. The aim of the present study was to explore the potential neuroprotective effects of Tan IIA in sciatic nerve transection injury. We investigated the possible beneficial effects of Tan IIA in promoting nerve regeneration after nerve transection injury in rats. Nerve transection injury was induced in male Sprague-Dawley rats by left sciatic nerve transection. After neuroanastomosis, the rats were intraperitoneally (IP) injected with 6 mg/kg, 15 mg/kg, or 40 mg/kg Tan IIA once daily for 12 weeks; the vehicle and positive control groups were injected with normal saline and mecobalamin (MeCbl, 100 μg/kg), respectively. Axonal regeneration and functional recovery were evaluated by a range of morphological and functional measures 12 weeks after neuroanastomosis. The administration of 15 mg/kg and 40 mg/kg Tan IIA and MeCbl achieved better axonal regeneration with significant restoration of motor function as well as a marked decrease in Fluoro-Gold (FG)-labeled neurons and increased nerve regeneration. At 12 weeks post-surgery, 40 mg/kg Tan IIA showed a better neuroprotective effect than 15 mg/kg Tan IIA and MeCbl. There were no statistical differences between the 15 mg/kg Tan IIA and MeCbl groups or the control and 6 mg/kg Tan IIA groups. Our findings demonstrate that Tan IIA can alleviate nerve injury and promote nerve regeneration in a sciatic nerve transection model in rats, providing supportive evidence for Tan IIA as an effective potential therapeutic remedy for peripheral nerve injury.