| Objective: Bone cancer pain is a type of pain caused by metastatic cancer cells invading the bone.When bone cancer pain occurs,along with the increased expression of chemokines,astrocytes are activated,which releases a variety of pro-inflammatory cytokines and produces pain signals.Emodin is the main active component of rhubarb,which has antibacterial,anti-inflammatory,liver and kidney protection,platelet aggregation inhibition,anti-tumor,immunosuppression and other effects.However,emodin has extremely poor solubility and low bioavailability,which seriously limits the study of its effects and mechanism.Nanomilk is a drug transmitter that can cross the blood-brain/blood-nerve barrier,and can enhance the tissue permeability and targeting of drugs.And then increase the bioavailability of the drug.In this study,emodin nano emulsion was prepared by phemulsification method,and the analgesic effect of emodin nano emulsion on bone cancer pain rats was discussed by preparing the rat model of bone cancer pain.Meanwhile,key targets of emodin in the treatment of bone cancer pain were explored based on network pharmacology and molecular docking method,and its mechanism of action was further studied to provide theoretical and experimental basis for its treatment of bone cancer pain.Methods: 1.18 SD rats with qualified pain threshold were selected and divided into sham operation group,model group and emodin group by random number table method.The rat bone cancer pain model was established by injecting MRMT-1 rat breast cancer cells into the tibial bone marrow cavity,and the rats in the sham operation group were injected with equal volume of HBSS buffer.The mechanical pain threshold of each group was detected before modeling and at 0,3,6,9,12 and 14 days after modeling.On the 14 th day of modeling,X-ray and tibial tissue HE staining were taken to determine the bone destruction and the success of modeling.After the successful establishment of the model,emodin group rats were injected intravaginally emodin nanoemulsion(5 mg/m L),sham operation group and model group were injected intravaginally with the same amount of normal saline.The mechanical pain threshold was measured 0-4 h after intrathecal injection.2.The common targets between emodin and bone cancer pain were collected through network pharmacology,and corresponding targets of chemokines were selected for molecular docking to predict the feasibility of the targets.3.After the behavioral test,the rats were killed.The expression of GFAP was detected by immunofluorescence.The expressions of GFAP,CXCR3 and TNF-α were detected by Western blot assay.The m RNA expression of IL-6,IL-1β and TNF-α was detected by fluorescence quantitative PCR.Results: 1.After the establishment of the bone cancer pain model,compared with the sham operation group,the mechanical pain threshold of rats in the model group was significantly reduced(P<0.05);After single injection of emodin nano milk,the mechanical pain threshold of emodin group rats was significantly increased within0-4 h compared with before injection(P<0.05).2.X-rays and HE staining showed that after 14 days of modeling,compared with the sham operation group,the rats in the model group had severe bone destruction and cancer cell infiltration.3.Network pharmacological analysis showed that CXCR3 was a key target of bone cancer pain;The results of molecular docking showed that CXCR3 had strong binding ability with rhein.4.Immunofluorescence results showed that: compared with sham operation group,spinal cord astrocyte activation increased in model group;Compared with the model group,the activation of spinal astrocytes in rats with bone cancer could be reduced after the emodin nanoemulsion intervention.5.Western blot test results showed that compared with sham operation group,the protein expressions of GFAP,CXCR3 and TNF-α in model group were significantly increased(P<0.05);After the emodin nanoemulsion intervention,the protein expressions of GFAP,CXCR3 and TNF-α in emodin group were significantly decreased compared with those in model group(P<0.05).6.Fluorescence quantitative PCR results showed that compared with sham operation group,m RNA expressions of IL-6,TNF-α and IL-1β in spinal cord of rats in model group were significantly increased(P<0.05);Emodin nanoemulsion can significantly decrease the m RNA expression of IL-6,TNF-α and IL-1β in spinal cord of rats(P<0.05).Conclusion: 1.Emodin has a certain analgesic effect on bone cancer pain rats.2.CXCR3 may be used as an analgesic target.Emodin nano-milk may alleviate bone cancer pain by inhibiting the expression of CXCR3 in rats with bone cancer pain,thereby affecting the activation of astrocytes and reducing the expression of pro-inflammatory cytokines. |
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