The Observation Of Inhaled Carbon Black Particle Matter On Rats With Chronic Sciatic Nerve Injury

Objective Aim of this study was to investigate the impact of inhaled carbon black particulate matter suspension in rats with neuropathic pain.Methods 36 S-D rats were divided into 3 groups,carbon black suspension(CBS)group,Escape group,control group(n=12 per group),and all rats received inhaled administration first.CBS group received Intratracheal injection of carbon black suspension for 10 days.Escape group received the same manner to CBS group with an additional 20 days secession from CBS environment.Control group received intratracheal injection of vehicle solution for 10 days.After inhaled administration,to establish neuropathic pain model,all rats received CCI surgery on their right hind paw and sham operation on the left.Mechanical withdrawal thresholds(MWT)was tested on post-CCI operation-1,3,5,7 days.Levels of tumor necrosis factor-?(TNF-?),interleukin-1 ?(IL-1 ?)in the sciatic nerve were assessed on post-operation 3,7 days.Lung tissues of CBS and Escape group were obtained for hematoxylin-eosin staining on post-CCI operation 3 day.Results HE staining showed carbon black particulate matter appeared in the blood vessels of lung.Before CCI surgery,the body weighs increasing rate of CBS group was significantly lower than control group.After CCI model estimated,on the contralateral hind paws to CCI surgery,no significant difference on MWT was observed,and only on day 3 after surgery,an upregulation of IL-1? was observed compared with control group(P<0.05).On the ipsilateral hind paws to CCI surgery,CBS group showed a decrease of MWT injured hind paws and upregulation of proinflammatory cytokines on day 3 and 7 after surgery(P<0.05).Escape group showed an increase of MWT and decreases of IL-1? on day 3,7 and TNF-? on day 3 compared to CBS group(P<0.05).No significant difference between control and escape group in MWT was observed,but an increase of IL-1? on day 3 after surgery was observed in Escape group compared to control group(P<0.05).Conclusion It may be concluded that Inhaled carbon black has the ability to aggravate neuropathic pain behavior of mechanical allodynia in rats,associated with increased local cytokines expressing in sciatic nerve.Avoiding contact with airborne particulate matters cloud alleviate the adverse effects.