Table 1.

The role of M2 macrophages in different pain models.

Region	Pain model	Species	Intervene	Effect	Reference
DRG	OA	Mice	Intrathecal injection of M2 macrophages	Mechanical hypersensitivity↓	(13)
Joint	K/BxN serum transfer model	Mice	–	The number of M2 macrophages at the joint does not consistently correlate with pain progression	(45)
DRG	Carrageenan-induced inflammatory pain	Mice	Intrathecal injection of M2 macrophages	The delayed pain relief caused by macrophage depletion is rescued.	(47)
Spinal cord	SNI	Mice	–	The expansion of spinal MRC1 macrophages is obviously blunted.	(50)
DRG	SNI	Mice	Intrathecal injection of M2-like bone marrow derived macrophages	M2 macrophages↑ Mechanical hypersensitivity↓	(51)
DRG	CIPN	Mice	Intrathecal injection of m-clodrosome	M2 macrophages↓ Resolution of mechanical allodynia↓	(52)
Injured nerve	CCI	Mice	Injection of IL-4 (200 ng) at the injured site from day 14 to day 21 after CCI	M2 macrophages↑ Mechanical hypersensitivity↓	(53)
Hind paw	Zymosan-induced inflammatory pain	Mice	Systemic injection of the MΦ toxin clodronate	Pain relief was delayed, which can be rescued by the transplantation of normal macrophages.	(54)

↑ means rise or promotion.↓ means decline or inhibition.