Decrease in Oxidative Stress Parameters after Post‐Ischaemic Recombinant Human Erythropoietin Administration in the Hippocampus of Rats Exposed to Focal Cerebral Ischaemia

Abstract

Recombinant human erythropoietin (rhEpo) is a multi-functional drug with antioxidant potential. However, the underlying molecular mechanisms of its action are still unclear. The purpose of this study was to investigate the effects of rhEpo on the brain infarct volume as well as on the levels of the neuronal damage, oxidative stress parameters and active caspase-3, nuclear factor erythroid 2-related factor 2 (Nrf2) and haemeoxygenase-1 (HO-1) expressions in the hippocampi of rats exposed to the right middle cerebral artery occlusion (MCAO) for 1 hr. Ischaemic animals received either vehicle or rhEpo (5000 IU/kg, i.p.) immediately or 3 hr after the induction of ischaemia. Sham-operated, vehicle-treated animals served as the control group. Rats were killed 24 hr after the onset of the ischaemic or sham experimental procedure. MCAO caused ipsilateral brain infarction within the striatum and cortex. In the CA1 region of the hippocampi, we did not find significant neuronal loss, but a statistically significant rise in the active caspase-3 and Nrf2 protein expressions was registered. We detected also significant increases in the hippocampal levels of oxidative stress parameters (thiobarbituric acid-reactive substances, superoxide dismutase, glutathione peroxidase). Post-ischaemic administration of rhEpo significantly reduced the brain infarct volume, decreased levels of all tested oxidative stress parameters and increased the Nrf2 expression level. These findings suggest that decrease in oxidative stress parameters in the hippocampus could be an early indicator of post-ischaemic neuroprotective effect of rhEpo in rats exposed to focal cerebral ischaemia and that this effect could be attributable to additional post-ischaemic activation of Nrf2 endogenous antioxidant system.

Early‐life N‐arachidonoyl‐dopamine exposure increases antioxidant capacity of the brain tissues and reduces functional deficits after neonatal hypoxia in rats

“…Decreased GPx2 mRNA level in brain tissue may indicate that 1.5 h after hypoxia the level of oxidative stress is reduced by NADA. A reduced levels of ROS and a decrease in GPx activity in rat brains were observed in the recent studies of pre-treatment with metabotropic glutamate receptors agonist (Bratek et al, 2018) and recombinant human erythropoietin (Mršić-Pelčić et al, 2017). The authors suggest that the protective effects of the therapeutic agents determined by the inhibition of ROS production and reduction of oxidative stress.…”

Neuroprotective Effect of the Recombinant Human Erythropoietin in the Enthorinal Cortex and Thalamus of Rats Exposed to Focal Cerebral Ischemia

“…Thus, it was shown that MCAO followed by 24 h of reperfusion causes significant neuronal damage in various brain regions. The predominant affected areas are mostly striatum and cortex due to the lack of collateral blood supply (2,18,19). It was described also that immunoreactivity for NeuN decrease significantly following MCAO (20), causing massive corticostriatal lesion with the peak of the damage 12-24 h following reperfusion (20,21).…”

“…However, most of the experimental research in various animal models that examined the neuroprotective effects of different doses of rhEpo on brain damage, proposed 5000 IU/kg of rhEpo as optimal dosage (32). It was also shown that rhEpo applied at various time-periods ranging from pre-treatment to up to 24 h after ischemia, exerts the best results when applied within the first 3 h after induction of ischemia (18).…”

Changes in Gene Expression and Neuroinflammation in the Hippocampus after Focal Brain Ischemia: Involvement in the Long-Term Cognitive and Mental Disorders

“…Apparent signs of apoptosis induction were observed in the rat hippocampus one day after MCAO [24]. The death of hippocampal cells via apoptosis was confirmed by the decrease in the expression of anti apop totic protein Bcl 2, as well as by the upregulated expres BIOCHEMISTRY (Moscow) sion of the pro apoptotic protein BAX [25] and the apop tosis executing enzyme caspase 3 in the hippocampus [22,26]. The increase in the number of apoptotic cells was accompanied with pronounced changes in the expression of mRNAs for the NMDA receptor sub units [27].…”

“…As established using microdialysis, the extracellular level of glutamate in the rat hippocampus increased within the first minutes of ischemia [21]. The first evidences of the so called delayed death of neurons in this structure were detected later than in the cortex and the striatum [22], as a rule, between 12 h and seven days after the ischemia, with the peak levels on day 4 [23]. Apparent signs of apoptosis induction were observed in the rat hippocampus one day after MCAO [24].…”