title: Estradiol attenuates spinal cord injury-induced pain by suppressing microglial activation in thalamic VPL nuclei of rats.
abstract: In our previous study we showed that central pain syndrome (CPS) induced by electrolytic injury caused in the unilateral spinothalamic tract (STT) is a concomitant of glial alteration at the site of injury. Here, we investigated the activity of glial cells in thalamic ventral posterolateral nuclei (VPL) and their contribution to CPS. We also examined whether post-injury administration of a pharmacological dose of estradiol can attenuate CPS and associated molecular changes. Based on the results,in the ipsilateral VPL the microglial phenotype switched o hyperactive mode and Iba1 expression was increased significantly on days 21 and 28 post-injury. The same feature was observed in contralateral VPL on day 28 (P<.05). These changes were strongly correlated with the onset of CPS (r(2)=0.670). STT injury did not induce significant astroglial response in both ipsilateral and contralateral VPL. Estradiol attenuated bilateral mechanical hypersensitivity 14 days after STT lesion (P<.05). Estradiol also suppressed microglial activation in the VPL. Taken together, these findings indicate that selective STT lesion induces bilateral microglia activation in VPL which might contribute to mechanical hypersensitivity. Furthermore, a pharmacological dose of estradiol reduces central pain possibly via suppression of glial activity in VPL region.
authors: Department of Pharmacology, Shahid Beheshti University of Medical Sciences, Evin, Tehran, Iran. Saghaei999@yahoo.com
authors: Elham
authors: E
authors: Saghaei
authors: Fatemeh
authors: F
authors: Abbaszadeh
authors: Kobra
authors: K
authors: Naseri
authors: Samar
authors: S
authors: Ghorbanpoor
authors: Mina
authors: M
authors: Afhami
authors: Ali
authors: A
authors: Haeri
authors: Farzaneh
authors: F
authors: Rahimi
authors: Masoumeh
authors: M
authors: Jorjani
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004195:Disease Models, Animal; D004958:Estradiol / Q000627:therapeutic use*; D004967:Estrogens / Q000627:therapeutic use*; D007839:Functional Laterality; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006930:Hyperalgesia / Q000188:drug therapy / Q000209:etiology; D008297:Male; D017628:Microglia / Q000187:drug effects*; D010146:Pain / Q000188:drug therapy* / Q000209:etiology; D010147:Pain Measurement / Q000187:drug effects / Q000379:methods; D017288:Pain Threshold / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000150:complications; D013997:Time Factors; D020651:Ventral Thalamic Nuclei / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*
chemical_list: D004967:Estrogens; D005904:Glial Fibrillary Acidic Protein; D004958:Estradiol