Antinociceptive Activities And Mechanisms Of Iridoid Glycosides Ectract Of Lamiophlomis Rotate (Benth.) Kudo

Objective:1. Establish and compare experimental neuropathic pain in rats modeling method.2. Extract and enrich the iridoid glycosides from lamiophlomis rotata(benth.)kudo(IGLR), andstudyits antinociceptive activities onneuropathic pain in rats, and explore the mechanism of its analgesic effect, provide the guidance for a basis of the LGLR clinical application.Method:1. Combining with the macro-porous adsorptive resinschromatographic method and polyamide chromatographic method, the iridoid glycosides of lamiophlomis rotate(benth.)kudo(IGLR)were extracted and enriched. At the same time the high-performance liquid chromatography(HPLC)were used to assay their idoidglycosides.2. We made the rat model of neuropathic pain by spared nerve injury of sciatic nerve3. Iridoid glycosides ectract of Lamiophlomis rotate(Benth.) Kudo use the gavage administration,and we detected the mechanical pain threshold to evaluate antinociceptive activities in vivo.4. We take the Lumbar intumescence part of rats. in accordance with the provisions of the kit, Nitric oxide synthase (NOS) activity and nitricoxide (NO) production of spinalcord were measured by spectrophotometry and its cytokine TNF-α, IL-1β, IL-10by enzyme linked immunosorbent assay. Standard immunohistochemical staining was used to provide information on changes of expression of phosphorylated CREB.The results provide a theoretical basis of Lamiophlomis rotate(Benth.) Kudo for further application and development of functional medicine, and health care products.Results:1. The results of the analysis of iridoid glycoside demonstrated:the ultraviolet absorption of the total iridoid glycoside was very similar to that of8-O-acetyl shanzhiside methylester and the maximum absorption peak was at235nm. The content of iridoid glycoside in the total iridoid glycoside was70.4%. RP-HPLC showed shanzhiside methylester and and8-0-acetyl-shanzhiside methylester are the main components in the aqueousand iridoid glycosides extract.2. Rat experiments show that the SNI model is successfully to model the formation of chronic neuropathic pain model. And rats in vivo test results show that Lamiophlomis rotate(Benth.) Kudocan improve the spirit of neuropathic pain in rats, increase activity, mechanical pain threshold was elevated to improve the symptoms of paw eversion.3. Experimental results show that in rats three dose groups of Lamiophlomis rotate(Benth.) Kudo,as high, medium and low dose (250mg/kg,800mg/kg,1000mg/kg) can significantly reduce the amountof NO and total NOS, as well as reduce the amountof cytokines TNF-α, IL-1β, IL-10in the spinal cord of neuropathic pain in the rat4. As standard immunohistochemical staining was used to provide information on changes of expression of phosphorylated CREB. thepositive optical density values of model group are higher than the normal group and sham group, while compared to three dose groups, model group is higher as well.Above all,the results proveLamiophlomis rotate(Benth.) Kudoand Kudo can reduce positive optical density of p-CREB.Conclusions:1. The IGLR was enriched and extracted successfully from the aqueous extract with the macro-porous adsorptive resins chromatographic method and polyamide chromatographic method.2. The total iridoid glycosides of IGLR have the significant antinociceptive effects in vivoto the model of neuropathic pain.3. The IGLR can significantly reduce the expression of NO and total NOS, but also to reduce the cytokines TNF-α, IL-1β expression and to increase expression of IL-10.Thusthe IGLR can significantly reduce the amount of astrocytes and spinal cord microglial cells of neuropathic pain in rats, can reduce nerve damage, and prevent the occurrence and development of neuropathic pain identified the analgesic activity of the effective parts of the IGLR is total iridoid glycosides,which further clarifiesthe connection between the analgesic active site and analgesic activity of the IGLR, and enriches the theory of traditional Chinese medicine for clinical use in Chinese herbal medicine. Therefore,the IGLR shoule be considered as a candidate for future studies on neuropathic pain.in addition, further exprimental long-term studies,should be carried out on the IGLR or its bioactive compound.