Very delayed neuronal loss occurs in the glomerular layer of the main olfactory bulb following transient ischemia in gerbils.

Olfactory dysfunction could happen following various insults such as ischemic-hypoxic state. Neurons of the main olfactory bulb (MOB) are resistant to ischemic damage. In the present study, we investigated the ischemia-related changes of neurons and glial cells in the glomerular layer (GL) of the gerbil MOB after transient ischemia. The number of NeuN-immunoreactive neurons became to decrease from 10 days after ischemic insult. Fifteen days after ischemic insult, astrocytes and microglia were increased in number. By 60 days after ischemia, NeuN-immunoreactive neurons were significantly decreased by 42% per glomerulus. At this time period, astrocytes and microglia were pronouncedly increased. This result indicates that neuronal loss must be much delayed in the GL following transient ischemia.