ABSTRACT
BACKGROUND: We have recently shown neuroprotective activity of the creatine amides in the focal cerebral ischemia in rats on the 280 mg/kg administration. In the present study, neuroprotective properties of creatylglycine ethyl ester fumarate (CrGEt) in rats with focal cerebral ischemia were explored in a wide dosage range (30-280 mg/kg, intravenous and intragastric). METHODS: Focal cerebral ischemia was induced by the middle cerebral artery occlusion (MCAO). RESULTS: The CrGEt administration 30 minutes before and at the last 5 minutes of MCAO dose dependently attenuated cerebral ischemic damage on 35%-65%, reduced neurobehavioral deficits, led to high neuronal survival in ischemic rat brains. The neuroprotective activity of CrGEt was mediated by its following abilities: (1) normalize the energy metabolism in the ischemic brains, maintaining adenosine triphosphate levels, and reducing lactate concentration; (2) inhibit the ischemia-reperfusion-related oxidative stress as evidenced by the increased activity of superoxide dismutase and the reduced levels of malondialdehyde. CrGEt served as a substrate for creatine kinase and a partial agonist of N-methyl-D-aspartate receptors; this partly explains mechanism of its neuroprotective action. CONCLUSIONS: In view of the previously mentioned results, CrGEt holds a promise as a compound for treatment of ischemic brain disorders.
Subject(s)
Brain/drug effects , Fumarates/pharmacology , Infarction, Middle Cerebral Artery/drug therapy , Neurons/drug effects , Neuroprotective Agents/pharmacology , Reperfusion Injury/prevention & control , Adenosine Triphosphate/metabolism , Animals , Antioxidants/pharmacology , Behavior, Animal/drug effects , Brain/metabolism , Brain/pathology , Brain/physiopathology , Cell Survival/drug effects , Creatine Kinase/metabolism , Cytoprotection , Disease Models, Animal , Dose-Response Relationship, Drug , Drug Partial Agonism , Drug Stability , Energy Metabolism/drug effects , Excitatory Amino Acid Agonists/pharmacology , Fumarates/metabolism , Half-Life , Infarction, Middle Cerebral Artery/metabolism , Infarction, Middle Cerebral Artery/pathology , Lactic Acid/metabolism , Male , Malondialdehyde/metabolism , Neurons/metabolism , Neurons/pathology , Neuroprotective Agents/metabolism , Oxidative Stress/drug effects , Rats, Wistar , Receptors, N-Methyl-D-Aspartate/agonists , Receptors, N-Methyl-D-Aspartate/metabolism , Reperfusion Injury/metabolism , Reperfusion Injury/pathology , Superoxide Dismutase/metabolismABSTRACT
Prolonged oral creatine administration resulted in remarkable neuroprotection in experimental models of brain stroke. However, because of its polar nature creatine has poor ability to penetrate the blood-brain barrier (BBB) without specific creatine transporter (CRT). Thus, synthesis of hydrophobic derivatives capable of crossing the BBB by alternative pathway is of great importance for the treatment of acute and chronic neurological diseases including stroke, traumatic brain injury and hereditary CRT deficiency. Here we describe synthesis of new hybrid compounds-creatinyl amino acids, their neuroprotective activity in vivo and stability to degradation in different media. The title compounds were synthesized by guanidinylation of corresponding sarcosyl peptides or direct creatine attachment using isobutyl chloroformate method. Addition of lipophilic counterion (p-toluenesulfonate) ensures efficient creatine dissolution in DMF with simultaneous protection of guanidino group towards intramolecular cyclization. It excludes the application of expensive guanidinylating reagents, permits to simplify synthetic procedure and adapt it to large-scale production. The biological activity of creatinyl amino acids was tested in vivo on ischemic stroke and NaNO(2) -induced hypoxia models. One of the most effective compounds-creatinyl-glycine ethyl ester increases life span of experimental animals more than two times in hypoxia model and has neuroprotective action in brain stroke model when applied both before and after ischemia. These data evidenced that creatinyl amino acids can represent promising candidates for the development of new drugs useful in stroke treatment.
