Evaluation of MAPK pathway activation in brainstem induced by the masseter muscle inflammation
Nakatsuka Michiko, Kumabe Shunji, Gamoh Shoko, Akiyama Hironori, 주성숙, 김지윤, Ueda Katsura, Matsuda Yoshifumi, Shimizutani Kimishige, 신제원, Iwai Yasutomo,
소속 상세정보
( Nakatsuka Michiko ) - Osaka Dental University Department of Oral Anatomy
( Kumabe Shunji ) - Osaka Dental University Department of Oral Anatomy
( Gamoh Shoko ) - Osaka Dental University Department of Oral Radiology
( Akiyama Hironori ) - Osaka Dental University Department of Oral Radiology
주성숙 ( Jue Seong-Suk ) - Kyung Hee University Graduate School of Dentistry Department of Oral Anatomy
김지윤 ( Kim Ji-Youn ) - Kyung Hee University Graduate School of Dentistry Department of Oral Anatomy
( Ueda Katsura ) - Osaka Dental University Department of Oral Anatomy
( Matsuda Yoshifumi ) - Osaka Dental University Department of Oral Anatomy
( Shimizutani Kimishige ) - Osaka Dental University Department of Oral Radiology
신제원 ( Shin Je-Won ) - Kyung Hee University Graduate School of Dentistry Department of Oral Anatomy
( Iwai Yasutomo ) - Osaka Dental University Department of Oral Anatomy
KMID : 0355820140350010089
Abstract
To evaluate the inflammatory hyperalgesia induced by noxious stimulation of the masticatory muscles, we performed an immunohistochemical study on the expressions of phosphorylated-p38 (p-p38) mitogen activated-protein kinase (MAPK) and the distribution of activated microglia in the trigeminal subnucleus caudalis (Vc). The left masseter muscle (LMM) of Sprague Dawley rats (male, 250 g, n=60) was stimulated in the following methods: 1) L-L group (control); the LMM was injected with lipopolysaccharide (LPS, 2 μg/kg, 100μl) on the 1st day of the experiment. On day 2, the same site was injected with the LPS again. 2) L-S6 group (experimental); the LMM was injected with LPS (2 μg/kg, 100μl) on the 1st day of the experiment. On day 2, the same site was injected with 6 % sodium chloride solution (S6, 100 μl, 5 times per 90 min). Rats were allowed to survive for 1 day, 7 days or 14 days after the last injection. The brainstems were dissected and cut
with a cryostat (at 30 μm thickness). These specimens were investigated with anti-TNFα (masseter muscle), the bradykinin receptor B2 (BKRB2, masseter muscle), anti-p-p38 MAPK (brainstem) and anti-Iba1 (ionized calcium-binding adapter molecule 1: Iba1, a marker for microglial activity; brainstem) enzyme-labeled antibody method. The specimens were observed and evaluated using a light microscope (LM) mounted with an Olympus FX380 3CCD digital camera system connected with a FLvFs software (Flovel Image Filling System, Tokyo, Japan). In both groups, the TNF-α and the BKRB2-immunoreactive (IR) cells were observed until 7 days after stimulation. In the experimental group, the LM histology indicates that p-p38 MAPK and Iba1-IR cells were particularly localized in the left Vc until 14 days after stimulation. In the experimental group, 7 days or 14 days after nociception, the p-p38 MAPK-IR cells were recognized in the contralateral and ipsilateral in the Vc. The results suggest that the prolonged MAPK activity in the Vc is related to central sensitization in chronic pain of the masseter muscle.
키워드
masseter muscle; chronic pai
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