Several molecular changes occur following axotomy, such as gene up-regulation and down-regulation. In our previous study using Affymetrix arrays, it was found that after the axotomy of sciatic nerve, there were many novel genes with significant expression changes. Among them, neuronatin (Nnat) was the one which expression was significantly up-regulated. Nnat was identified as a gene selectively expressed in neonatal brains and markedly reduced in adult brains. The present study investigated whether the expression of Nnat correlates with symptoms of neuropathic pain in adult rats with transected sciatic nerve. Methods: Western blotting,. | Chen et al. Journal of Biomedical Science 2010 17 41 http content 17 1 41 a NSC Tha cost of publication In Journal of Blomodlcal Science Is bome by tlM National Science Council Taiwan JOURNAL OF BIOMEDICAL SCIENCE RESEARCH Open Access Altered neuronatin expression in the rat dorsal root ganglion after sciatic nerve transection Kuan-Hung Chen 1 2 Chien-Hui Yang1 Jiin-Tsuey Cheng2 Chih-Hsien Wu1 2 Wei-Dih Sy1 and Chung-Ren Lin 1 3 Abstract Background Several molecular changes occur following axotomy such as gene up-regulation and down-regulation. In our previous study using Affymetrix arrays it was found that after the axotomy of sciatic nerve there were many novel genes with significant expression changes. Among them neuronatin Nnat was the one which expression was significantly up-regulated. Nnat was identified as a gene selectively expressed in neonatal brains and markedly reduced in adult brains. The present study investigated whether the expression of Nnat correlates with symptoms of neuropathic pain in adult rats with transected sciatic nerve. Methods Western blotting immunohistochemistry and the Randall and Selitto test were used to study the protein content and subcellular localization of Nnat in correlation with pain-related animal behavior. Results It was found that after nerve injury the expression of Nnat was increased in total protein extracts. Unmyelinated C-fiber and thinly myelinated A-Ỗ fiber in adult dorsal root ganglions DRGs were the principal subpopulation of primary afferent neurons with distributed Nnat. The increased expression of Nnat and its subcellular localization were related to mechanical hyperalgesia. Conclusions The results indicated that there was significant correlation between mechanical hyperalgesia in axotomy of sciatic nerve and the increased expression of Nnat in C-fiber and A-Ỗ fiber of adult DRG neurons. Background Neuropathic pain in humans can be caused by peripheral nerve injury resulting in spontaneous .
