Abstract
Purpose::
Creatine has previously been demonstrated to protect neuronal cells in animal models of Parkinson’s disease, Huntington’s disease and traumatic injury to the brain and spinal cord. It is believed that impared energy metabolism is a contributing factor of neuronal death and that the neuroprotective effects of creatine supplementation are achieved through energy buffering and transport. In this study, the efficacy of creatine as a neuroprotectant was investigated in an in vitro rat retinal glutamate excitotoxic model.
Methods::
Rat retinal neuronal cultures (7 - 8 days) were treated for 24 hours with media containing glutamate (0 - 1000 microM), with or without 24 hours pre-treatment with 2 mM creatine. Creatine was left in the culture media during glutamate treatment. Comparison of glutamate-induced excitotoxic injury in the presence of creatine to excitotoxic injury without creatine was measured using the MTT cell viability assay. Immunocytochemisty was performed on cell cultures and positive staining was counted in a 20x field of view.
Results::
In the absence of creatine 0 - 1000 microM glutamate resulted in a dose-dependent decrease in cell culture viability, whereas the glutamate treatment in the presence of creatine resulted in greater cell viability as determined by the MTT assay. Cells staining positive for calretinin were more susceptible to glutamate excitotoxicity than cells that stained positive for calbindin. The survival of calretinin and calbindin positive cells was improved in the presence of creatine.
Conclusions::
Rat retinal cultures subjected to glutamate-induced excitotoxic injury and pre-treated for 24 hours with 2mM creatine display improved neuronal survival and mitochondrial function.
Keywords: neuroprotection • cell survival • excitatory neurotransmitters