ABSTRACT
Periodontal disease is a common chronic inflammatory disease in humans, It is believed that neurogenic inflammation plays an important role in pathogenesis of this disorder. Therefore the neuronal expression of the pro-inflammatory mediators are altered. This study was to determine the neuronal profile of neuropeptides mRNA in the trigeminal ganglia in a model of experimental periodontitis in rats, Periodontitis was induced in male rats by intragingival injection of lipopolysaccharide adjacent to the second right mandibular molar, The animals were killed seven days after lipopolysaccharide injection and the right trigeminal ganglia were processed for in situ hybridisation for neuropeptides [beta-preprotachykinin, alpha-calcitonin gene-related peptide mRNAs and somatostatin]. Expression of these neuropeptides' mRNAs was significantly increased only in small neurons in the mandibular division of the trigeminal ganglion from the periodontitis Group. No significant changes in neuropeptide mRNA levels were seen in the maxillary and ophthalmic divisions of the trigeminal ganglia. The upregulation of neuropeptides mRNAs in periodontal disease suggests a role for neurogenic mechanisms in the development of periodontal disease