Aging-Related Phenotypic Conversion of Medullary Microglia Enhances Intraoral Incisional Pain Sensitivity.
Int J Mol Sci
; 21(21)2020 Oct 23.
Article
in En
| MEDLINE
| ID: mdl-33114176
ABSTRACT
Activated microglia involved in the development of orofacial pain hypersensitivity have two major polarization states. The aim of this study was to assess the involvement of the aging-related phenotypic conversion of medullary microglia in the enhancement of intraoral pain sensitivity using senescence-accelerated mice (SAM)-prone/8 (SAMP8) and SAM-resistant/1 (SAMR1) mice. Mechanical head-withdrawal threshold (MHWT) was measured for 21 days post palatal mucosal incision. The number of CD11c-immunoreactive (IR) cells [affective microglia (M1)] and CD163-IR cells [protective microglia (M2)], and tumor-necrosis-factor-α (TNF-α)-IR M1 and interleukin (IL)-10-IR M2 were analyzed via immunohistochemistry on days 3 and 11 following incision. The decrease in MHWT observed following incision was enhanced in SAMP8 mice. M1 levels and the number of TNF-α-IR M1 were increased on day 3 in SAMP8 mice compared with those in SAMR1 mice. On day 11, M1 and M2 activation was observed in both groups, whereas IL-10-IR M2 levels were attenuated in SAMP8 mice, and the number of TNF-α-IR M1 cells increased, compared to those in SAMR1 mice. These results suggest that the mechanical allodynia observed following intraoral injury is potentiated and sustained in SAMP8 mice due to enhancement of TNF-α signaling, M1 activation, and an attenuation of M2 activation accompanying IL-10 release.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Facial Pain
/
Aging
/
Tumor Necrosis Factor-alpha
/
Interleukin-10
/
Microglia
Type of study:
Diagnostic_studies
/
Etiology_studies
/
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
Int J Mol Sci
Year:
2020
Document type:
Article
Affiliation country:
Japan