Protective effect of hypothermia during ischemia in neural cell cultures.

Hypothermia offers protection from the effects of ischemia in small animals. We have recently shown that similar to small animals, hypothermia may also be protective in an astrocytic model of "simulated ischemia" in cell culture. This study was designed to look at the protective effects of hypothermia in cultures of cerebellar granular (glutamatergic) and cortical (GABAergic) neurons. We used LDH release into the medium as an indicator for neuron damage. Experiments were all done in sister cultures, in groups of six cultures at two temperatures (37 and 32 degrees Celsius). The duration of ischemia was three hours in cerebellar granular neuronal cell cultures and six hours in cortical neurons. LDH release was measured immediately after the insult. Hypothermia protected both granular and cortical neurons. In granular cells, LDH release was 62 +/- 18 at 32 degrees and 212 +/- 15 at 37 degrees (p = 0.02). Cortical neurons showed LDH release of 15 +/- 2 at 32 degrees and 32 +/- 2 at 37 degrees (p = 0.005). Our study suggests that similar to astrocytes, the protective effects of hypothermia are evident in neuronal cell cultures from the cerebellum and the cerebral cortex. Cell culture systems should prove useful techniques in understanding mechanisms of hypothermic protection during simulated ischemia in neurons from different sites.