AIM. To investigate whether Nrf2 expression and activation occurs during ischemia – reperfusion injury of spinal cord, in which cells the Nrf2 expression is observed and does the Nrf2 signalling pathway activity depends on the time of reperfusion. To investigate whether manganese porphyrin (MnP) presents neuroprotective effects through transcription factors Nrf2 and NF-kB. MATERIAL AND METHODS. The study was conducted on experimental model of spinal cord IR injury by clamping abdominal aorta during 45 min in rats. MnP was administered just before the surgery and every 12 h post surgery. The animals were sacrificed after 1, 6, 48 and 168 h of reperfusion. Neurologic score was evaluated during 7 days. Spectrophotometric measurement of lipid peroxidation products, protein carbonyl content and levels of antioxidant enzyme activity were performed. Using Western blot levels of expression of SOD1, SOD2, GSH-Px, Nrf2, HO-1 and NF-kB were measured. The expressions of mRNA HO-1, Gclc and CAT were analyzed by PCR method. Immunofluorescent analysis was used to show localization and intensity of expression of Nrf2, NF-kB, NeuN, ChaT, GFAP, Iba1 and PLP1. RESULTS. The neurologic score was significantly better during 48 and 168 h of reperfusion in group with MnP treatment. MnP significantly decreased the levels of lipid peroxidation products and the protein carbonyl content during 48 and 168 h of reperfusion. Also MnP significantly increased the activity of SOD enzymes during 6 h of reperfusion, while the activity of GPx enzyme was increased even during 48 h of reperfusion. IR injury significantly increased expression of Nrf2 protein in nuclear fraction during 6 h of reperfusion while MnP does not effect Nrf2 expression. Nrf2 signalling pathway target protein, HO-1, was significantly increased even during 48 h of reperfusion. Also the level of mRNA HO-1, Gclc and CAT expression was increased. MnP significantly decreased expression of NF-kB protein in nuclear fraction during 6 h of reperfusion. Histological analysis revealed Nrf2 expression in CHaT positive neurons localized in anterior horn of grey matter. Mean intensity of Nrf2 expression increased with the longer reperfusion time and was directly dependant on IR injury. MnP decreased astrocyte number in anterior funiculus of white matter during 6 and 48 h of reperfusion. By analysing NF-kB expression and activation we showed that NF-kB was expressed in astrocytes depending on IR injury as well as on time of reperfusion. MnP significantly decreased number of cells with nuclear positive NF-kB expression. CONCLUSION. IR injury induces expression and activation of Nrf2 protein depending on time of reperfusion. MnP acts protective by decreasing expression of NF-kB protein in nuclear fraction.