Hi everyone, I'm hoping to get some advice or suggestions on how to best approach this scenario. Eventually I plan to do microdialysis in the rat brain after I inject an AAV into the cortex, however, there is a 3 week span between microdialysis and the viral injection. Typically I do one viral injection through a burr hole in the skull and then suture the head wound without any cannula insertion. When I go to do microdialysis 3 weeks later, I thought that I would be able to see a partially healed burr hole on the skull but that is not the case. I'm wondering if I should just insert the cannula and perform viral injections on the same day, then have the animals live with the cemented cannulas for 3 weeks or if there may be a way to mark the skull somehow for where I inject? I'm apprehensive about having the animals survive with a headcap for 3 weeks but it's looking like this may be the only option.
Any help you could offer would be greatly appreciated!
Thanks!
In terms of how long can an animal remain healthy with a cannula inserted - we routinely use cannulated mice for optogenetics for at least a month - these are permenant implanted fibres usually deep into the hypothalamus. Providing the canula are well cemented in and you keep checking them the animals should be fine for 3 weeks. However, cannula do fall out over time due to getting bashed on cage 'furniture' especially if they are big. I would increase n per group by at least 1or 2 to account for losses.
Hopefully that helps!
Cheers, Ed
Thank you Ed! Do you have anything to plug the cannula like a screw cap? I’m worried about infection due to the dummy probes we use to plug the cannula not being screw cap-like. They just fit into the cannula and the rats could protentially grab hold of it and pull it out, leaving the hole exposed.
Are you using a stereotaxic coordinate for viral vector? If so this should be repeatable, if not extremely close. Also high powered magnification of the stereotaxic location (area) should show some sort of partially healed bur hole, even small
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