Table1.

Characteristics of M1 and M2 microglia

	Markers	Factors secreted and recruited	Function
M1	MHC-II, CD16, CD32, CD80 (B7-1), CD86 (B7-2), and CD40 (TNFR)	TLR2, TLR4, INF-γ, complement C3a and C5a, IL-1β, IL-6, IL-12, IL-23, TNF-α, CX3C, NADPH oxidase, NO synthase, CD40, and complex II (MHC-II)	Proinflammatory; nerve injury
M2	Ym-1, CD206, CD68, and arginase-1	IL-10, TGFβ, glucocorticoids, arginase-1, Ym-1, and CD206	Anti-inflammatory; nerve repair; suppressing oxidative injury

In contrast to the function of M1-type cells, M2-type cells have an immunoprotective function