RÉSUMÉ
Objective:To explore the feature of FOS expression in oxytocin-and vasopressin-positive neurons in the hypothalamic paraventricular nucleus(PVN)under different status of diabetes mellitus(DM).Methods:Intraperito-neal injection of vehicle or STZ in mice was conducted to establish control or diabetes model.Mechanical sensitivity was evaluated by von Frey filament tests to distinguish diabetic neuropathic pain(DNP)from without-pain group(DWP).The expression of FOS,oxytocin(OXT)-and vasopressin(VP)-positive neurons,as well as their double labeling was detected by immunohistochemical and immunofluorescent staining.Cell counting and comparison were made in groups.Results:FOS expression was easily detected in the PVN in the three groups(Control group,DNP group and DWP group)at 7 days,while that in DWP and DNP groups at 28 days was hardly detectable,with the number being signifi-cantly different from the 7 days group(P＜0.05 or 0.001).Likewise,compared with the control group,immunofluo-rescent signals for VP and OXT staining in the DNP and DWP groups also showed a trend of weakening as the modeling time increased(P＜0.05).The cell counting after double staining for VP or OXT with FOS showed that,in the DWP group at 7 days,the number of VP and FOS double-labeled neurons was 74.33±22.10,accounting for(56.64± 7.52)％of VP-positive cells,whereas the double labeling rate for OXT and FOS was only(10.44±3.14)％.In the DNP group at 7 days,the number of OXT and FOS double-labeled neurons was 51.00±31.80,accounting for(18.50 ±9.51)％of OXT-positive neurons,whereas the double labeling rate for VP and FOS was only(9.34±3.27)％.In contrast to these changes in 7 days group,the expression of FOS decreased sharply in the group of 28 days,thereby al-most no double-labeled neurons.Conclusion:The plasticity changes of oxytocin-and vasopressin-positive neurons in the PVN are different depending on the status of pain and non-pain,and the stage of disease progression.Understanding the changes is of great significance for unravelling the neural mechanism of diabetes and its complications.
RÉSUMÉ
Diabetic neuropathic pain （DNP） is one of the common complications of diabetic peripheral neuropathy， which is difficult to be cured. The clinical manifestations of DNP include reduced pain threshold， neuropathic pain in extremities， and abnormal pain. Studies have demonstrated that nuclear factor-kappa B （NF-κB）， mitogen-activated protein kinase （MAPK）， Toll-like receptor 4 （TLR4）， nuclear factor erythroid 2-related factor 2 （Nrf2）， and phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt） signaling pathways are involved in the treatment of DNP by inhibiting the activation and release of inflammatory cytokines ［e.g.， tumor necrosis factor-alpha （TNF-α） and interleukin （IL）］， regulating inflammation-mediating factors ［e.g.， reactive oxygen （ROS）， inducible nitric oxide synthase （iNOS）， cyclooxygenase （COX-2）， and NF-κB inhibitor （IκB）］， suppressing neurogenic inflammation， destroying the persistent damage of peripheral nerves， and repairing damaged peripheral nerves. The literature of modern medical research has demonstrated that the treatment of DNP with Chinese herbal medicines is associated with the signaling pathways above. They can treat DNP by regulating the expression of key proteins in the signaling pathways to control neurogenic inflammation and repair diabetic peripheral neuropathic damage. By summarizing the available studies， this review aims to provide a reference for the in-depth research on Chinese herbal medicines in the treatment of DNP and give new insights into the protection of diabetic peripheral nerves and the treatment of DNP with Chinese herbal medicines.
RÉSUMÉ
OBJECTIVE@#To observe the occurrence time of neuralgia and the expression of purinergic ligand-gated ion channel 7 receptor (P2X7R) in the dorsal horn of the spinal cord after intraperitoneal injection of streptozotocin (STZ) in diabetic rats, and to explore the effect of electroacupuncture (EA) and pretreatment of EA on the heat pain threshold and expression of P2X7R in the spinal dorsal horn in rats with diabetic neuropathic pain (DNP), and to explore the possible mechanism of EA for DNP.@*METHODS@#PartⅠ: Thirty male SD rats were randomly selected from 64 male SD rats as the control group; the remaining rats were given intraperitoneal injection of STZ (10 mg/mL) at a dose of 65 mg/kg to establish the diabetes model, and 30 rats were successfully modeled as the model group. The control group and the model group were divided into three subgroups respectively at 7, 14 and 21 days, with 10 rats in each subgroup. Body mass, fasting blood glucose (FBG) and thermal pain threshold were recorded at 7, 14 and 21 days after injection; the expression of P2X7R in spinal dorsal horn was detected by Western blot. PartⅡ: Eight SD rats were randomly selected from 35 male SD rats as the blank group, and the remaining 27 rats were given intraperitoneal injection of STZ (10 mg/mL) at a dose of 65 mg/kg to establish the diabetes model. The 24 rats with successful diabetes model were randomly divided into a DNP group, an EA group and a pre-EA group, 8 rats in each group. Fifteen to 21 days after STZ injection, the EA group received EA at "Zusanli" (ST 36) and "Kunlun" (BL 60), continuous wave, frequency of 2 Hz, 30 min each time, once a day; the intervention method in the pre-EA group was the same as that in the EA group. The intervention time was 8 to 14 days after STZ injection. The body mass, FBG and thermal pain threshold were recorded before STZ injection and 7, 14 and 21 days after STZ injection; the expression of P2X7R in spinal dorsal horn was detected by Western blot 21 days after injection.@*RESULTS@#PartⅠ: Compared with the control group, in the model group, the body mass was decreased and FBG was increased 7, 14 and 21 days after STZ injection (P<0.01), and the thermal pain threshold was decreased 14 and 21 days after STZ injection (P<0.05), and the expression of P2X7R in spinal dorsal horn was increased 7, 14 and 21 days after STZ injection (P<0.05, P<0.01). PartⅡ: Compared with the blank group, in the DNP group, the body mass was decreased and fasting blood glucose were increased 7, 14 and 21 days after STZ injection (P<0.01). Compared with the DNP group, in the pre-EA group, the heat pain threshold was increased 14 and 21 days after STZ injection (P<0.05), while in the EA group, the heat pain threshold was increased 21 days after STZ injection (P<0.01), and the expression of P2X7R in the dorsal horn in the EA group and the pre-EA group was decreased (P<0.01).@*CONCLUSION@#The diabetic neuropathic pain is observed 14 days after STZ injection. EA could not only treat but also prevent the occurrence of DNP, and its mechanism may be related to down-regulation of P2X7R expression in the dorsal horn of the spinal cord.