Fig. 3.

Patterns of 4C4-ir microglial profiles after deafferentation by cautery.

Olfactory bulbs after deafferentation by cautery of the right olfactory organ were labeled with 4C4. Boxes indicate areas magnified in A’-F”. A) At 1 h, there was no apparent difference in distribution of 4C4-ir profiles between the left, internal control and right, deafferented (*) olfactory bulbs. The few 4C4-ir profiles had a ramified (arrowheads) morphology in both the left (A’) and right (A”) bulbs. B) At 4 h, there was a substantial increase in 4C4-ir profiles in the injured bulb (*). In the intact bulb, labeled profiles were ramified (B’), while on the deafferented side, most 4C4-ir profiles showed an amoeboid (arrow) morphology (B”). C) At 12 h, the tissue appeared to be inflamed, and there were fewer 4C4-ir profiles in both olfactory bulbs than the previous timepoint. Most labeled profiles were of the ramified morphology in the intact (C’) and the damaged (C”) bulbs. D) At 24 h, there was another increase in 4C4-ir profiles in the deafferented bulb (*). While the intact bulb (D’) continued to exhibit ramified microglia, the deafferented bulb (D”) showed more amoeboid microglia. E) At 48 h, there were even more 4C4-ir profiles in the deafferented bulb (*), and while the intact bulb showed ramified microglia (E’) the affected bulb displayed many amoeboid and transitioning (long arrows) morphologies (E”). F) At 72 h, the total level of microglia continued to increase in the deafferented bulb (*). The intact bulb had ramified cells (F’), while the deafferented bulb showed mostly microglia with the transitioning morphology (F”). Scale bar =200 μm for A–F; 20 μm for A’-F”.