Bilateral Macrophage Responses in the Rat Dorsal Root Ganglia following Unilateral Nerve Injury and Contralateral Sham-operation
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| Year of publication | 2012 |
| Type | Conference abstract |
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| Description | Unilateral nerve injury results in cellular and molecular changes of the contralateral dorsal root ganglia (DRG) that may contribute to the induction and maintenance of neuropathic pain. A contribution of nerve injury and proper surgical treatment to the changes in DRG of neuropathic pain models is unknown. Therefore, the goal of our experiments was to distinguish between intensity of macrophages invasion into the cervical and lumbar DRG in response to experimental nerve injury and surgical treatment alone. In our experiments, we used 10 adult female rats operated on i/ unilateral chronic constriction injury of the sciatic nerve (CCI), ii/ unilateral spared nerve injury of the sciatic nerve (SNI), iii/ unilateral chronic constriction injury of the sciatic nerve with sham operation on contralateral side (CCI+sham), iv/ unilateral spared nerve injury of the sciatic nerve with sham operation on contralateral side (SNI+sham), v/ unilateral sham operation alone. Two naive rats were used as control. The invasion of macrophages in DRG was detected immunohistochemically using mouse monoclonal antibodies anti-ED1 a week after surgical treatment. The ratio of ED1 positive area to entire area of neuronal region of each lumbar and cervical DRG section was measured by means of NIS Elements image analysis system (Laboratory Imaging, Prague, Czech Republic). The data differences were evaluated by Mann-Whitney test using STATISTICA software. ED1 positive cells areas considered to be activated macrophages were observed in the DRG of naive rats. Significant elevation of ED1+ macrophages was found both in cervical and lumbar DRG one week after all types of surgical treatments. Invasion of macrophages was distinct after unilateral sciatic nerve injury (CCI, SNI) and lower after sham surgery. Strikingly, after combined damage (CCI+sham, SNI+sham), the amount of ED1+ macrophages was lower both in the ganglia associated and non associated with damaged nerve when compared with ganglia from CCI and SNI rats. A possible explanation for this phenomenon could be the depletion of macrophage activation after two sided injury. |
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