Study On The Molecular Mechanism Of Melatonin Relieving Itching

Purpose: First,48/80 and CQ-induced acute itch models were established on ICR mice,including psoriasis-like and dry dermatosis-like chronic pruritus models,melatonin treatment,pharmacology,behavioral methods,Flow cytometry,molecular cell biology and other technologies are used to study the molecular mechanism of melatonin in inhibiting acute pruritus and chronic pruritus.Method:(1)Circadian rhythm experiments were performed on adult ICR mice,normal light from 8 am to 8 pm,and complete darkness from 8 pm to 8 am.After two weeks,they were randomly divided into five groups: vehicle(Vehicle),psoriasis(PSO),psoriasis + melatonin(PSO + Melatonin),and dry skin disease(AEW),Dry skin disease + melatonin group(AEW+Melatonin group).One week after the model was built,blood was taken from the eyelid at six o'clock in the morning and taken every six hours until six o'clock in the morning.The ELISA kit was used to detect the melatonin content in the blood.(2)Adult male ICR mice were injected with 100 ug of 48/80 and 200 ug CQ in the neck.The three different administration methods were intradermal injection,intraperitoneal injection,and intrathecal injection of different doses of melatonin.Quantitative analysis of the itching behavior of mice.(3)ICR adult male mice were randomly divided into three groups.One group only had hair removal treatment,no drug(Vehicle group),one group applied imiquimod cream(PSO group),and the last group applied imiquimod.Special cream,and on the third,fifth and seventh days,melatonin(PSO+Melatonin group)was injected intraperitoneally with imiquimod cream,5-9 mice in each group.Using behavioral methods and HE staining to detect whether melatonin can relieve psoriasis-like pruritus and proliferation of mouse keratinocytes.(4)ICR adult male mice were randomly divided into three groups.One group was treated only for hair removal and no drug(Vehicle group).One group was first coated with acetone and ether for 1:1,30 seconds,and then for 15 seconds(AEW).Group),twice a day,the last group was smeared with acetone and ether for 1:1,30 seconds,followed by water for 15 seconds,and on the third,fifth,and seventh days before the application of acetone,ether,and water.Melatonin(AEW+Melatonin group),5-9 per group.Using behavioral methods and HE staining,it was determined whether melatonin can relieve dry skin disease-like pruritus and proliferation of mouse keratinocytes.(5)The quantitative real-time PCR was used to detect the mRNA expression of inflammatory factors and receptors in two chronic pruritus models and melatonin treatment.(6)Using a pharmacological method,48/80 and CQ were mixed intradermally with mouse melatonin and melatonin receptor antagonists 4-4 PDOT and Luzindole,and detected by behavioral methods.Mouse scratching behavior.In the psoriasis and dry skin chronic itch models,EX527 was administered intraperitoneally for the first half hour of melatonin on the third,fifth,and seventh days.Behavioral methods were used to detect the scratching behavior of the mice.See if it can reverse melatonin to inhibit chronic itching.(7)ICR mice were randomly divided into control group,psoriasis group,psoriasis plus melatonin group,dry skin disease group,dry skin disease plus melatonin group,and after 7 days of modeling,mice were taken.The skin and neck were expanded and the spinal cord and skin tissues were examined.The expression of p-AKT and p-ERK was detected by Western blot.The relationship between melatonin and chronic pruritus and p-AKT and p-ERK was determined.Result:(1)(1)In the circadian rhythm experiment,the melatonin rhythm of the control group was normal,the melatonin content in the psoriasis and dry skin mouse model was dysregulated,and the melatonin content was increased after the melatonin treatment.(2)Pharmacological experiments showed that in the acute itch model of mice,melatonin can inhibit pruritus induced by 48/80 and CQ by intradermal,intraperitoneal and intrathecal methods.(3)The results of behavioral experiments showed that melatonin was injected intraperitoneally on the third,fifth,and seventh days in two models of psoriasis and dry skin in chronic itching.The results showed that melatonin can Inhibit chronic itch.(4)The results of quantitative PCR showed that the inflammatory factors were significantly elevated in the chronic itch model.In the psoriasis model,melatonin can inhibit the expression of IL33 and ST2.Melatonin can inhibit the expression of IL31 and IL31 RA in the dry skin disease model.(5)The flow cytometry results of ND7-23 cells showed that melatonin can inhibit 48/80 and CQ-induced ROS,and in the psoriasis model,the anti-oxidation gene Sod2 was significantly reduced,giving melatonin Can then reverse its expression.(6)Pharmacological experiments showed that in the mouse model of acute itch,melatonin receptor antagonist 4-4PDOT,Luzindole can reverse melatonin inhibition 48/80 and CQ-induced pruritus.(7)Western blotting results showed that melatonin inhibited the expression of p-AKT on psoriasis skin,which can relieve the expression of p-ERK on the spinal cord.Conclusion:(1)Chronic pruritus mouse model melatonin circadian dysregulation.(2)Melatonin can inhibit acute itching and chronic itching in mice.(3)Antioxidative stress and anti-inflammation play an important role in melatonin inhibition in the induction of acute pruritus and chronic pruritus.(4)P-AKT and p-ERK play a role in the inhibition of melatonin in chronic pruritus.