| Objective:To investigate the function of Krebs cycle of astrocytes in acute injury, chronic persistent injury and central sensitization of the spinal cord induced by formalin.Method:This study made inflammatory pain model of rat through injecting formalin (5%,50L) in the planar of right hind legs, and then observed the behavior changes in rats after intrathecal injection with lnmol/10L fluorocitrate (FC) and (or)500nomol/10L L-glutamate (Glu).Results:(1) compared with the control group, in the acute phase: the spontaneous nociceptive behavior (lick bite claws and shrinkage leg reflection) was inhibited by injecting FC intrathecally, but this effect was reversed by injecting Glu;(2) In chronic phase: compared with the control group, single injection with FC intrathecally (at20min before formalin injection) significantly improved the mechanical threshold in rats ipsilaterally in2days (P<0.01, P<0.05), but improved the mechanical hyperalgesia in rats contralaterally in1day (P<0.05); multiple injections with FC intrathecally (at20min before formalin injection and in1day,2day for3days after formalin injection) significantly inhabited the mechanical hyperalgesia in rats ipsilaterally in3-7days (P<0.01, P<0.05), and in rats contralaterally in2-7days (P <0.01, P<0.05); compared with the control group, single injection with FC intrathecally (in9days after formalin injection) significantly inhabited the mechanical hyperalgesia in rats ipsilaterally and contralaterally at third hour (P<0.05), but the mechanical hyperalgesia recovered at six hour; multiple injections with FC intrathecally (in9,10,11days after formalin injection) transiently inhabited the mechanical hyperalgesia in rats ipsilaterally and contralaterally at third hour.Conclusion:the Krebs cycle in astrocytes was involved in the formation of central sensitization in the spinal cord induced by formalin, but did not play a leading role in the maintenance of central sensitization in the spinal cord. |
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