I am analysing synapse formation during early postnatal development using the brains of postnatal day 2 (P2) and postnatal day 10 (P10) wild-type and knockout mice. Through Western blot analysis, I have found that synapse numbers increase significantly with age in the wild-type mice, but this effect is not found with the knockout mice, suggesting that the knockout of the gene of interest leads to impaired synapse formation.
I would like to confirm my findings using an in vitro model. I am new to neuronal cultures but one way I think this can be achieved is to prepare primary neuronal cultures from P2 wild-type and knockout mice, and use immunocytochemistry to quantify synapse numbers when they reach the "P10 stage" (e.g. fix and label neurons when they reach 8 days in vitro).
However, I would like to know if the cultured neurons at 8 days in vitro would be equivalent to the state of neurons (e.g. in terms of their growth and morphology) in vivo in P10 mice or is this a faulty assumption? Any insights are appreciated.