In vitro Models of Brain Ischemia: The Peptidergic Drug Cerebrolysin Protects Cultured Chick Cortical Neurons from Cell Death

Glutamate (1 mM), iodoacetate (0.01 mM) and ionomycin (0.25 mu M) are reported to induce several characteristics of ischemia and neuronal degeneration in vitro, e.g. glutamate and ionomycin lesion result in a disturbance of Ca2+ homeostasis, iodoacetate impairment leads to an inhibition of energy metabolism, suppression of protein synthesis and generation of oxygen free radicals. In this study these three lesion models were used to investigate the effects of the nootropic drug Cerebrolysin (Cere) on the survival of cortical neurons in culture and on the occurrence of apoptosis. The viability of the cells was evaluated with the colorimetric MTT-reduction assay. Apoptosis was detected with Bisbenzimide (Hoechst: 33258), a fluorescent DNA stain. Administration of Cere resulted in dose dependent neuroprotection independent from the kind of lesion. In the glutamate model the drug almost doubled neuronal viability compared to lesioned controls. After acute glutamate exposure Cere reduced the number of apoptotic cells significantly. In spite of the protective efficacy after cytotoxic hypoxia induced by iodoacetate, the drug significantly increased the number of apoptotic neurons, indicating a shift from necrosis to apoptosis. In contrast to previous studies investigating acute ionomycin lesions, the chronic Ca2+-overload used here did not increase the abundance of apoptosis compared to the unlesioned control. Summarizing the findings it can be suggested that Cere is able to stabilize Ca2+ homeostasis, to protect protein synthesis and to counteract neuronal death in different in vitro models of ischemia.