Neuroprotective effects of Tacrolimus (FK-506) and Cyclosporin (CsA) in oxidative injury


Sandeep K. Agrawal, Department of Surgery, Section of Neurosurgery, 6009 Poynter Hall, University of Nebraska Medical Center, Omaha, NE 68198-6250. Tel: +402-559-4567; Fax: 402-559-7779; E-mail:


The detrimental effects of hypoxic damage to central nervous system lead to energy depletion, free radical formation, lipid peroxidation (LPO), and increased calcium. We hypothesized that in vitro tacrolimus (FK-506) and cyclosporine A (CsA) could be protective against hypoxic damage in spinal cord. Dorsal columns were isolated from the spinal cord of adult rats and injured by exposure to hypoxic condition for 1 h, and treated with FK-506 (0.1 μM) and CsA (0.1 μM). After injury, reperfusion was carried out for 2 h. Tissues were collected, processed for biochemical assays, and 2,3,5-triphenyltetrazolium chloride (TTC) staining. Spinal cord hypoxia caused a significant decrease (P < 0.001) in mitochondrial ATP (30.64%) and tissue reduced glutathione (GSH) (60.14%) content. Conversely, a significant increase (P < 0.001) in tissue LPO level (57.77%) and myeloperoxidase (MPO) activity (461.24%) was observed in hypoxic group. Mitochondrial swelling was also significantly increased in hypoxic group (90.0%). Treatment with either FK-506 or CsA showed that significant neuroprotective effects (P < 0.05–0.01) were measured in various parameters in hypoxic groups. FK-506 and CsA treatment showed increase in ATP by 11.19% and 16.14% while GSH content increased by 66.46% and 77.32%, respectively. Conversely, LPO content decreased by 18.97% and 24.06% and MPO level by 42.86% and 18.66% after FK-506 and CsA treatment. Calcium uptake was also decreased in mitochondria as exhibited by the increase in absorbance by 11.19% after FK-506 treatment. TTC staining also showed increased viability after FK-506 and CsA treatment. In conclusion, present study demonstrates the neuroprotective effect of FK-506 and CsA treatment against spinal cord hypoxia induced damage is mediated via their antioxidant actions.