The Mechanism Of Endothelin In Pain Conduction In Ovarian Cancer

The Human Development Index predicts that more than 20 million people will be diagnosed with cancer each year by 2030.Although the survival rate of cancer patients has greatly improved due to the advances in medical technology,the incidence of cancer related pain has also increased year by year.Among them,ovarian cancer is the gynecologic tumor with the second highest incidence of female reproductive system malignancy.Its occurrence is occult.70%-80% of the patients have reached the advanced stage when they are found,and 75%-95% of the patients with advanced ovarian cancer need to endure the cancer pain.At present,the treatment of cancer pain is mainly based on the "three ladders" treatment proposal of the cancer pain of the World Health Organization(WHO),but the pain control of cancer pain slightly worse than expected,and the need to face problems such as the toxic side effects of NSAID drugs and the risk of opioid addiction,so it brings many troubles to the treatment of cancer pain.The WHO has identified cancer pain as a global health problem.In recent years,several chemical mediators are increasingly moving towards the forefront of the pathophysiology of cancer pain.One of the hotspots is endothelin(ET).ET consists of 21 amino acids,and there are 3 subtypes: ET-1,ET-2 and ET-3.They play a physiological role through binding with endothelin receptors.Endothelin receptor is a 27 transmembrane G protein coupled receptor,which is divided into endothelin A receptor(ETAR)and endothelin B receptor(ETBR).It has been reported that the use of endothelin receptor antagonists can improve the cancer pain of liver cancer,breast cancer and prostate cancer,but there are few reports on cancer pain in ovarian cancer.The purpose of this study is to explore the role of endothelin and its receptors in ovarian cancer pain through the orthotopic transplantation model of ovarian cancer,and to investigate the mechanism of endothelin in ovarian cancer pain through the experiment of dorsal root ganglion cells in mice,to provide a new idea for the treatment of cancer pain.Part 1 The role of endothelin and its receptor antagonist in ovarian cancer painObjective: To observing the changes of the cancer pain at different time points in the orthotopic implantation model of ovarian cancer with endothelin receptor agonists(ET)and endothelin receptor antagonist(BQ788,BQ123),and to investigate the effects of endothelin and its receptors on ovarian cancer pain.Method:Randomly divide 5-week old healthy female BALB-C mices into 5 groups: the sham operation group,the model control group,the ET-1 administration model group,the BQ123 administration model group and the BQ788 administration model group.To establish the orthotopic implantation model of ovarian cancer in mice,and intraspinal injection administration on the 9th,11 th,and 13 th day after operation.To record the threshold of left and right hind paw pain on the 1st day before operation,3rd,7th,9th,11 th,and 13 th days after surgery.Result: The mauchly sphericity test was performed among the experimental grouping,the time of measuring mechanical withdrawal threshold,and the left or right hind paw selected for measuring the threshold,P>0.05.The MWT in the model group was lower than that in the blank control group(P<0.05),and there was no significant change compared with the ET group(P>0.05).The MWT of the left hind paws in all model groups was lower than that in the right(P<0.05).BQ123 and BQ788 can play an analgesic effect in ovarian cancer model mice(P<0.05),but there was no significant difference between them(P>0.05).Conclusion: In the orthotopic transplantation model of ovarian cancer,the factors influencing the mechanical hyperalgesia in mice include: the number of cancer days of cancer,the intraspinal injection of ET,BQ123,BQ788 and the left and hind paws of mice,and these factors interact with each other.It was suggested that ET and its receptors were involved in the occurrence of ovarian cancer pain.The degree of cancer pain in the model mice is related to the number of cancer days,the location of tumor growth and the analgesic treatment.Part 2 The mechanism of endothelin in pain conduction in ovarian cancer painObjective: To investigate the effect of endothelin receptor agonists(ET)on intracellular calcium concentration in dorsal root ganglia(DRG)cells,and to explore the mechanism of endothelin in ovarian cancer pain.Method:To acutely isolate and culture mice DRG cells,and to observe the effect of ET-1 on the intracellular calcium concentration in DRG cells by the FLIPR after adding EGTA,Nifedipine,SKF96365,EGTA + Dantrolene sodium and EGTA+2-APB.Result: ET-1 increased the intracellular calcium concentration in DRG cells.Compared with ET-1 alone,adding ET-1 after adding EGTA,Nifedipine and SKF96365 respectively,the increase of calcium concentration in DRG cells decreased(P<0.05),but there was no difference among the 3 groups(P>0.05).Compared with adding ET-1 after adding EGTA,the concentration of calcium in DRG cells in adding ET-1 after adding EGTA + Dantrolene sodium was similar(P>0.05),and the concentration of DRG cells in adding ET-1 after adding EGTA +2-APB was not changed(P<0.05),and there was a difference between these 2 groups.Conclusion: ET may mediate the production of cancer pain by increasing the intracellular calcium concentration in DRG cells.ET has two pathways to increase intracellular calcium concentration:1.Activation of the L-type calcium channel on the membrane of DRG cells causes the entry of extracellular calcium into the cell.2.Activation of IP3-sensitive calcium channels on intracellular calcium stores,and induces the release of calcium ions from calcium stores,leading to an increase in intracellular calcium concentration.