Objective: To investigate the protective effect of mild hypothermia on rat astrocytes with traumatic or ischemic injury.
Methods: Rat astrocytes in primary culture were subjected to scratching or hypoxic injury and exposed to normothermia (37 degrees celsius;) or hypothermia (34 or 32 degrees celsius;) for 24 h. The morphology of the astrocytes was evaluated by live/dead staining, and the cell injury was measured by lactate dehydrogenase (LDH) release assay.
Results: As the temperature reduced the LDH release rate from the cells in hypoxic group decreased significantly, to (11.48 - or + 1.53)% at 34 degrees celsius; and (3.79 - or + 0.45)% at 32 degrees celsius; as compared to that in normothermia [(33.02 - or + 3.58)%] in the absence of rat white blood cells (WBC) (P<0.001). LDH release rate of the hypoxic cells further decreased in the presence of rat WBC to (51.14 - or + 2.17 )% at 37 degrees celsius;, (19.53 - or + 4.37)% at 34 degrees celsius; and (16.68 - or + 1.47)% at 32 degrees celsius; (P<0.001). In the scratched cells, with or without WBC, LDH release rate showed no significant variation between the 3 temperatures (P>0.05).
Conclusion: Mild hypothermia offers obvious protective effects on rat astrocytes against ischemic damage but not against mechanical injury.