Author:
Soma Chihiro,Hitomi Suzuro,Oshima Eri,Hayashi Yoshinori,Soma Kumi,Shibuta Ikuko,Tsuboi Yoshiyuki,Shirakawa Tetsuo,Kikuiri Takashi,Iwata Koichi,Shinoda Masamichi
Abstract
AbstractPatients with persistent pain have sometimes history of physical abuse or neglect during infancy. However, the pathogenic mechanisms underlying orofacial pain hypersensitivity associated with early-life stress remain unclear. The present study focused on oxidative stress and investigated its role in pain hypersensitivity in adulthood following early-life stress. To establish an early-life stress model, neonatal pups were separated with their mother in isolated cages for 2 weeks. The mechanical head-withdrawal threshold (MHWT) in the whisker pad skin of rats received maternal separation (MS) was lower than that of non-MS rats at postnatal week 7. In MS rats, the expression of 8-hydroxy-deoxyguanosine, a marker of DNA oxidative damage, was enhanced, and plasma antioxidant capacity, but not mitochondrial complex I activity, decreased compared with that in non-MS rats. Reactive oxygen species (ROS) inactivation and ROS-sensitive transient receptor potential ankyrin 1 (TRPA1) antagonism in the whisker pad skin at week 7 suppressed the decrease of MHWT. Corticosterone levels on day 14 increased in MS rats. Corticosterone receptor antagonism during MS periods suppressed the reduction in antioxidant capacity and MHWT. The findings suggest that early-life stress potentially induces orofacial mechanical pain hypersensitivity via peripheral nociceptor TRPA1 hyperactivation induced by oxidative stress in the orofacial region.
Funder
JSPS KAKENHI
Dental Research Center, Nihon University School of Dentistry
Uemura Fund, Nihon University School of Dentistry
Sato Fund, Nihon University School of Dentistry
Japan Agency for Medical Research and Development
Nihon University Multidisciplinary Research Grant
Publisher
Springer Science and Business Media LLC