Bisphosphonate Nanoemulsion Attenuates Inflammatory Response In Rat Experimental Autoimmune Neuritis

Background As a familiar autoimmune disease,Guillain-Barré syndrome(GBS)mainly damaging peripheral nervous system.People of all ages can suffer this disease,pathological changes are characterized by demyelination of peripheral nerve fibers and infiltration of inflammatory cells around the blood vessels.Clinical manifestations include leg,arm or facial muscle paralysis,decreased or absent reflexes,and autonomic dysfunction etc.At present,the clinical treatment of GBS is limited and the effect is not good,so it is necessary to research more effective and convenient treatment methods.Experimental autoimmune neuritis(EAN)is an autoimmune disease first proposed by Wakesman,which is a demyelinating peripheral neuropathy induced by CD4+ T cells.EAN has the same immunology,pathology,electrophysiological characteristics,clinical features and other aspects as GBS,as an ideal animal model for studying GBS.Macrophages are the main effects cells In EAN disease,and have antigen-presenting properties and direct phagocytosis of axon myelin,which is the most important cause of peripheral neuropathy.Previous studies have shown that inhibiting the activity of macrophages or knocking out macrophages can delay the progression of EAN disease.Bisphosphonate(BP)has traditionally been a clinical drug for the treatment of bone diseases and calcium metabolic diseases.It is mainly used to treat osteoporosis,osteoarthritis,hyperkalemia caused by malignant tumor bone metastasis.Especially for Osteoporosis that with increase of bone fragility and fracture rate,which is characterized by a decrease in bone mass and destruction of bone structure.In addition,some studies have found that it has a certain therapeutic effect on a variety of malignant tumors.It is worth noting that recent studies have also confirmed that bisphosphonates play a role in anti-inflammatory for treatment in a variety of experimental animal inflammatory responses and EAN autoimmune disease models.However,due to the existence of The blood-brain nerve barrier in the treatment of the nervous system diseases,the dose of bisphosphonate peripheral blood is required to be increased,which is liable to cause various adverse reactions,largely restricted The use of bisphosphonates in the treatment of neuroinflammation.Nanoemulsion is a drug delivery medium that can penetrates the blood-brain barrier,enhances drug permeability and tissue cell targeting,thereby increasing the bioavailability of the drugs.This study intends to prepare bisphosphonate nanoemulsion using nanoemulsion Lipofundin(Lipo)and bisphosphonate.To tested potential therapeutic effects of nano-emulsion of bisphosphonate in the Experimental autoimmune neuritis(EAN)and to investigate the mechanism,therefore provide theoretical and experimental basis for clinical treatment of GBS.Methods:(1)RAW 264.7 cell were used to evaluate the effects of bisphosphonate nanoemulsion(BP nanoemulsion)on the inflammatory reaction and polarization of macrophages.(2)Lewis rats were injected with P2 peptides mixed with complete Freund’s adjuvant(CFA),to inducted EAN,After immunization of rats,given nano-emulsion of bisphosphonate(BP nanoemulsion)or bisphosphonate(BP)alone treatments,compare to control group,assessed neurological signs,Weight change,Mechanical allodynia.(3)Luxol Fast Blue(LFB)staining was applied to show myelin,inflammatory cell infiltration and pathological changes in the PNS were evaluated by Immunohistochemistry.(4)The expression of inflammatory cytokines mRNA level in PNS was showed by Real-time PCR.Results:(1)Compared with the control group,BP nanoemulsion treatments inhibited inflammatory response and induced phenotypic switch of macrophage polarization towards M2 subtype in cell culture.(2)BP nanoemulsion ameliorated neurological disease and body weight loss,shortened disease duration,ameliorated mechanical allodynia,and inhibited the progress of experimental autoimmune neuritis.(3)BP nanoemulsion alleviated Perivascular demyelination and reduced accumulation of macrophages and other immune cells in sciatic nerves of EAN rats.(4)BP nanoemulsion decreased expression of inflammatory cytokines IL-1β、IL-17、iNOS and MMP-9 in sciatic nerves of EAN rats.Conclusion:BP nanoemulsion was capable of reducing the accumulation of immune cells and attenuated the release of inflammatory cytokines,significantly suppressed EAN progression,reduced neuropathic pain,BP nanoemulsion therefore may be considered of a potential therapeutic choice for human neuropathies.