P R Kramer1, L L Bellinger. 1. Department of Biomedical Sciences, Baylor College of Dentistry, Texas A&M Health Science Center, Dallas, USA. pkramer@bcd.tamhsc.edu
Abstract
BACKGROUND: Previous studies have shown 17β-estradiol will reduce temporomandibular joint (TMJ) inflammation and hypersensitivity in female rats. Although male rats contain significant amounts of oestradiol, it was unknown whether a physiological concentration of 17β-estradiol would attenuate male TMJ inflammation and nociception. METHODS: Intact and castrated rats were given a physiological concentration of oestradiol to examine first, if oestradiol will affect male TMJ nociception/inflammation and, second, if administration of oestradiol would act synergistically with endogenous male hormones to attenuate TMJ nociception. The hormonally treated rats were given TMJ injections of complete Freund's adjuvant (CFA) and then nociception was measured using a validated method in which a lengthening in meal duration is directly correlated to the intensity of deep TMJ nociception. Inflammation was assayed by quantitating pro-inflammatory gene expression. RESULTS: Meal duration was significantly lengthened after TMJ CFA injection and this lengthening was significantly attenuated in the castrated but not intact males after administering a physiological concentration of oestradiol. A physiological concentration of 17β-estradiol also significantly increased IL-6 expression in the inflamed TMJ of castrated males while 17β-estradiol did not alter IL-1β, CXCL2 and CCL20 expression. Castration increased pro-inflammatory mediators IL-6, IL-1β and CXCL2 suggesting male sex hormones were anti-inflammatory. Calcitonin gene-related peptide in the trigeminal ganglia was unchanged. CONCLUSIONS: Similar to females, male rats with TMJ inflammation showed a reduced nociceptive response after treatment with a physiological concentration of oestradiol suggesting the effects of oestradiol treatment were not constrained by organizational processes in the males.
BACKGROUND: Previous studies have shown 17β-estradiol will reduce temporomandibular joint (TMJ) inflammation and hypersensitivity in female rats. Although male rats contain significant amounts of oestradiol, it was unknown whether a physiological concentration of 17β-estradiol would attenuate male TMJ inflammation and nociception. METHODS: Intact and castrated rats were given a physiological concentration of oestradiol to examine first, if oestradiol will affect male TMJ nociception/inflammation and, second, if administration of oestradiol would act synergistically with endogenous male hormones to attenuate TMJ nociception. The hormonally treated rats were given TMJ injections of complete Freund's adjuvant (CFA) and then nociception was measured using a validated method in which a lengthening in meal duration is directly correlated to the intensity of deep TMJ nociception. Inflammation was assayed by quantitating pro-inflammatory gene expression. RESULTS: Meal duration was significantly lengthened after TMJ CFA injection and this lengthening was significantly attenuated in the castrated but not intact males after administering a physiological concentration of oestradiol. A physiological concentration of 17β-estradiol also significantly increased IL-6 expression in the inflamed TMJ of castrated males while 17β-estradiol did not alter IL-1β, CXCL2 and CCL20 expression. Castration increased pro-inflammatory mediators IL-6, IL-1β and CXCL2 suggesting male sex hormones were anti-inflammatory. Calcitonin gene-related peptide in the trigeminal ganglia was unchanged. CONCLUSIONS: Similar to females, male rats with TMJ inflammation showed a reduced nociceptive response after treatment with a physiological concentration of oestradiol suggesting the effects of oestradiol treatment were not constrained by organizational processes in the males.
Authors: Luana Fischer; Karla E Torres-Chávez; Juliana T Clemente-Napimoga; Dany Jorge; Franco Arsati; Maria Cecília F de Arruda Veiga; Claudia H Tambeli Journal: J Pain Date: 2008-07 Impact factor: 5.820
Authors: Waldiceu A Verri; Thiago M Cunha; Sérgio H Ferreira; Xiaoqing Wei; Bernard P Leung; Alasdair Fraser; Iain B McInnes; Foo Y Liew; Fernando Q Cunha Journal: Eur J Immunol Date: 2007-12 Impact factor: 5.532
Authors: Rebecca S Hornung; William L Benton; Sirima Tongkhuya; Lynda Uphouse; Phillip R Kramer; Dayna Loyd Averitt Journal: Front Integr Neurosci Date: 2020-05-08
Authors: Phillip R Kramer; Mahesh Rao; Crystal Stinson; Larry L Bellinger; Paul R Kinchington; Michael B Yee Journal: Front Integr Neurosci Date: 2018-10-12