| Local anesthetics are promising for post-operative analgesia.Professor Ma Chao’s research group developed a new formula of bupivacaine preparation previously,which was prepared by single emulsification-solvent evaporation method,encapsulated by polylactic acid-glycolic acid copolymer(PLGA).The average particle size was within nanometer scale by scanning electron microscopy.Previously,Professor Ma Chao’s team conducted drug release studies in vitro,and preliminary studies on the efficacy and safety of the new preparation in rodent’s model of chronic compression of the dorsal root ganglion.In the present study,this new formula of bupivacaine nanoparticle was administered in rat plantar incision model for examining the hypothetical efficacy in acute postoperative pain management.The experiments of three parallel groups were conducted,in which the bupivacaine nanoparticle,the bupivacaine hydrochloride solution,and normal saline were respectively used.After acquisition of the baseline data,the rats underwent plantar incision modeling operation,and the corresponding drug of 0.1 ml was infiltrated in the surgical area in the meantime.The rats’ behaviors related to spontaneous pain were observed and recorded,and peripheral blood samples were collected for the detection of the level of bupivacaine.The results showed that a single injection of the suspension(10 mg/ml)without other analgesic medicine or technique had no obvious inhibitory effect on spontaneous pain-related behaviors in acute postoperative stage of rat plantar incision model.Neuropathic pain is closely related to chronic pain.The definition of neuropathic pain is the pain arising as a direct consequence of a lesion or disease affecting the somatosensory system.The abnormal ectopic excitability of afferent neurons is one important pathogenic mechanism of neuropathic pain.Whether is FcyRIa involved in it?FcyRIa is a macromolecule and receptor playing an important part in the immune system.This pilot study was conducted to explore the association of FcyRIa with the pathophysiological mechanisms of the rat model of Chronic Compression of the Dorsal root ganglion(CCD).The first half of this study was to evaluate the quality of the disease model,and methods adopted included observation of the general status of rats,mechanical stimulus with modified von Frey hairs and radiant heat stimulus applied to plantar surface of the foot,dissection performed to locate which segment of intervertebral foramen each rod resided after euthanasia.The results of behavior examination didn?t achieve the expectations,and the fulfillment of the animal model could not be ascertained.Though it was proud that the ways and points with anatomic landmark to identify the segment of vertebra during CCD surgery,were summarized.The tuber coxae parallels L6,the rostral end of iliac crest is close to zygapophy seal j oint of L5-6,and the vertebra L1-4 of rats have clear processus accessories.The second part of the study were to detect FcyRIa in rat5 s dorsal root ganglion in vivo by immunohistochemistry with fluorescent markers.Postive signals of FcyRIa in somata of neurons were observed and photographed.However,fluther experiments are required to decide whether they were false positive or not.Conclusion:Till now there is no clear evidence stating that FcyRIa is associated with the pathophysiological mechanisms of CCD model. |
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