Objective To investigate the effects of lactoferrin on microglial activation in the spinal cord in the rat model of neuropathic pain (NP).Methods Thirty-two male SD rats with the weight of 200-220 g were randomly divided into 4 groups, i.e. the control group , the neuropathic pain group , the minocycline group and the lactoferrin group , each consisting of 8 animals.The sciat-ic nerve was only exposed but not ligated in the animals of the control group , and 8μl of normal saline were injected intrathecally .The neuropathic pain model was produced by placing loosely constrictive ligatures around the common sciatic nerve in the animals of the oth -er groups.Eight μl of normal saline were injected intrathecally in the animals of the neuropathic pain group .One hundred μl of lacto-ferrin were given intrathecally in the animals of the lactoferrin group , while the same amount of minocycline was also given intrathecally in the animals of the minocycline group .Following medication , the paw withdrawal latency ( PWL) was detected every 30 minutes by u-sing thermal nociceptive stimulus with a total of 180 minutes.After detections for 7 times, the rats were sacrificed for the collection of spinal dorsal horn .The expression of Iba-1 was determined by immunofluorescence , and then statistical analyses were made according-ly.Results PWL for the animals of the neuropathic pain group was obviously prolonged , as compared with that of the control group , and statistical significance could be seen , when comparisons were made between them (P<0.05).PWL for the animals of both the mi-
nocycline group and the lactoferrin group was prolonged , as compared with that of the neuropathic pain group , also with statistical signif-icance(P<0.05).No statistical significance could be noted in PWL for the animals of the minocycline group and the lactoferrin group , when comparisons were made between them (P>0.05).This was an indirect indication that lactoferrin could alleviate neuropathic pain through the inhibition of the activation of spinal microglia .The expression levels of Iba-1 in the animals of the minocycline group and the lactoferrin group , as well as the neuropathic pain group , were significantly decreased , and statistical significance could be seen , when it was compared with that of the control group (P<0.05).The expression levels of Iba-1 in the animals of the minocycline group and the lactoferrin group were also significantly decreased , as compared with that of the neuropathic pain group , also with statistical signifi-cance(P<0.05).No statistical significance was shown in PWL , when comparisons were made between the minocycline group and the lactoferrin group(P>0.05).This was also an indirect indication that lactoferrin could alleviate neuropathic pain through the inhibition of the activation of spinal microglia .Conclusion Lactoferrin could alleviate neuropathic pain through the inhibition of the activation of spinal microglia , which had certain medical value in the clinical practice of anesthesia .

Objective To investigate the effects of lactoferrin on activity of PKG in spinal dorsal horn in a rat model of neuropathic pain(NP).Methods Thirty-two male SD rats weighing 200-250 g were randomly divided into4 groups(n = 8 each): sham operation group(group S),NP group,lactoferrin group and KT5823(an inhibitor of PKG)group.Neuropathic pain was produced by placing loosely constrictive ligatures around the common sciatic nerve in group NP,lactoferrin and KT5823,while the sciatic nerve was only exposed but not ligated in groupS.In group S and NP,normal saline 10 μl + 50% dimethyl sulfoxide(DMSO)10 μl were injected intrathecally.Lactoferrin 100 μg + 50% DMSO 10 μl were given intrathecally in group lactoferrin.Lactoferrin 100 μg + KT5823 10 μl were given intrathecally in group KT5823.The paw withdrawal latency(PWL)to a thermal nociceptive stimulus was measured every 30 min within 180 min after administration.The rats were then sacrificed and the spinal cord was removed.The activity of PKG in the spinal dorsal horn was determined by immunofluorescence.Results Compared with group NP and KT5823,the PWL was significantly prolonged after administration in group lactoferrin and the PKG activity was significantly increased in group lactoferrin(P ＜ 0.05).There was no significant difference in the parameters mentioned above between group NP and group KT5823(P ＞ 0.05).Conclusion Lactoferrin reduces NP by inhibiting the activity of PKG in spinal dorsal horn in rats.