The Mechanism Of Acupuncture In Regulating Fractalkine/CX3CR1 Pathway To Inhibit Retinal Microglia

Objective: Irreversible apoptosis of photoreceptor cells is a key pathological change in retinal degenerative diseases.Microglia was activated after photoreceptor cell damage,which is confirmed to promote apoptosis and aggravate neuronal damage,but the dialogue mechanism between them is not yet Clearly,inhibiting this process is key to slowing or stopping the progression of the disease.Studies suggest that acupuncture has a certain protective effect on photoreceptor cells,and chemokine Fractalkine may be an important factor in the functional dialogue between photoreceptor cells and microglia.Therefore,Exploring the exact effect of acupuncture in this study for inhibiting the activity of retinal microglia and protecting photoreceptor cells,and preliminary explored the key mechanism by which the regulation of Fractalkine/CX3CR1 pathway inhibits retinal microglia and blocks photoreceptor cell apoptosis.Methods: The photoreceptor cells apoptosis model of rats was established by intraperitoneal injection of 50 mg/kg N-methyl-N-nitrosourea(MNU)solution.Animals were randomly divided into four groups: normal group,model group,acupuncture group and vitamin A group,and continued treatment for fourteen days.After the experiment,The Hematoxylin and eosin staining,TUNEL method and immunofluorescence method were used to observe the changes of retinal tissue structure and thickness of outer nuclear layer,apoptosis of photoreceptor cells and expression of microglia(OX-42)in retina.The levels of inflammatory factors IL-1?and TNF-? were detected by ELISA.The protein expression of Fractalkine and CX3CR1 was detected by Western blot.Result: 1.The retinal photoreceptor cells were loose and disordered in the model group,the inner and outer ganglion cells were swollen,the thickness of the outer nuclear layer was significantly thinner,and increased the number of apoptosis in the photoreceptor layer,that suggesting photoreceptor cells were undergo apoptosis;small gelatin can be observed after modeling.The cell OX-42(+)gradually appeared in the retinal ONL,and the number increased with the prolongation of time,and the apoptosis peak of photoreceptor cells was earlier than the migration peak of microglia OX-42(+).2.Compared with the model group,the acupuncture group and the vitamin A group can increase the thickness of the ONL,reduce the activation and migration of the microglia,and the photoreceptor cells can preserve a certain amount.The inhibitory effect of acupuncture on microglia was better than that of vitamin A,and the difference was statistically significant(P<0.05).3.Acupuncture and vitamin A treatment can reduce the levels of inflammatory factors TNF-? and IL-1?,and the reduce ability of acupuncture is stronger than vitamin A(P<0.05).Compared with the model group,the expression level of Fractalkine and CXC3R1 protein is up-regulated in the acupuncture group,which was better than vitamin A group(P<0.05),there was no significant increase in the level of CXC3R1 protein in the vitamin A group(P>0.05).Conclusion: Acupuncture can inhibit the activation and migration of microglia to the outer nuclear layer of the retina,reduce or block the apoptosis of photoreceptor cells,and protect the retinal tissue cells.The mechanism is related to up-regulated the expression of retinal Fractalkine and CX3CR1 to inhibit the excessive activation of microglia,reduce the release of TNF-? and IL-1? in the retina,and reduce the damage of retinal tissue cells,so as to play a role in the prevention and treatment of retinal degenerative diseases.