PD-L1 is increased in the spinal cord and infiltrating lymphocytes in experimental allergic encephalomyelitis

Experimental allergic encephalomyelitis is a mouse model of human multiple sclerosis with similar pathology and pathogenesis. Thl cells play an important role in the pathogenesis of experimental allergic encephalomyelitis. This study determined the potential effect of programmed cell death 1 ligand 1 in the pathogenesis of experimental allergic encephalomyelitis induced by injecting myelin oligodendrocyte glycoprotein, complete Freund＇s adjuvant and Bordetella pertussis toxin into C57BL/6J mice. Experimental allergic encephalomyelitis mice developed disease and showed in- flammatory changes in the central nervous system by hematoxylin-eosin staining of spinal cord pathological sections, demyelination by Luxol fast-blue staining and clinical manifestations. The expression of programmed cell death 1 ligand 1 in mice was detected by immunohistochemistry, flow cytometry and western blot anatysis. The expression of programmed cell death 1 ligand 1 in the spinal cord and splenocytes of mice was significantly increased compared with normal mice. Our findings suggest the involvement of programmed cell death 1 ligand 1 in the pathogenesis of ex- perimental allergic encephalomyelitis and suggest this should be studied in multiple sclerosis.

Effect of olfactory ensheathing cell transplantation on myelin repair and motor function in a rat model of experimental allergic encephalomyelitis

BACKGROUND： Olfactory ensheathing cell transplantation can activate axonal regeneration and enhance myelin repair, which are beneficial for treating demyelinating diseases. OBJECTIVE： To explore the effects of olfactory ensheathing cell transplantation on myelin repair, synaptophysin expression, and motor function in a rat model of experimental allergic encephalomyelitis. DESIGN, TIME AND SETTING： A randomized, controlled experiment was performed at the Laboratory of Provincial Hospital affiliated to Shandong University between August 2006 and September 2007. MATERIALS： Dibenzylamine （Hoechst 33342）, luxol fast blue, and rabbit anti-rat synaptophysin antibody were provided by Sigma, USA. METHODS： Olfactory ensheatbing cells extracted from neonatal Wistar rats were cultured for 10-14 days and labeled with dibenzylamine. Spinal cord extracted from a healthy guinea pig was homogenized and equally mixed with complete Freund＇s adjuvant; thereafter, the mixture was intracutaneously injected into two posterior voix pedis of healthy male Wistar rats to establish models of experimental allergic encephalomyelitis. Rats were randomly divided into a control encephalomyelitis group and an olfactory ensheathing cell transplantation group, 36 rats in each group. Physiological saline （2 μ L） or an olfactory ensheathing cell suspension （2 μ L） was separately injected along lateral cerebral ventricle at day 7 post-model induction. MAIN OUTCOME MEASURES： The migration and distribution of olfactory ensheathing cells were observed under fluorescence microscopy; myelin repair was detected using hematoxylin-eosin staining and luxol fast blue staining; synaptophysin expression was measured using immunohistochemical staining; motor function was evaluated using a motor function scale. RESULTS： Olfactory ensheatbing cells could survive in vivo and migrate to the distal end of the transplant focus and spinal cord, and survived 21 days. Hematoxylin-eosin staining and luxol fast blue staining indicated that myelin in the transplantation group was intact, and the inflammatory focus gradually disappeared. Transplantation increased synaptophysin expression （P 〈 0.05 versus control） and motor function （P 〈 0.05）. CONCLUSION： Olfactory ensheathing cell transplantation can promote myelin repair, increase synaptophysin protein expression, and ameliorate motor function in a rat model of experimental allergic encephalomyelitis.

Immunity phenomena following olfactory ensheathing cell transplantation into experimental allergic encephalomyelitis rat brain

Olfactory ensheathing cells （OECs） can promote axonal regeneration and remyelination for the treatment of spinal cord injury. OECs can also treat experimental allergic encephalomyelitis （EAE）, but it remains unclear whether OECs might be rejected by the immune system in the brain including the destruction of the blood-brain barrier under inflammation, the release of inflammatory factors, the activation of local antigen-presenting cells （e.g., microglia cells） and antigen drainage. We found that OECs expressed major histocompatibility complex （MHC）-I molecules on the cell surface, barely expressed MHC-II, but MHC-II could be induced by interferon-v, suggesting that OECs have certain immunogenicity. When OECs were transplanted into normal animal brains, no OECs were phagocytosed by dendritic cells in the cervical lymph node, and OECs did not induce lymphocyte proliferation, which indicates that OECs share some immune privilege under normal conditions. However, OECs in the rat EAE brain were phagocytosed by dendritic cells in the cervical lymph node and enhanced lymphocyte proliferation. These findings suggest that OECs are rejected because of increased immunogenicity in EAE brain, and that brain inflammation, in particular activated dendritic cells, may be a prerequisite for rejecting OECs.

Effect of neuropeptide Y on white matter demyelination and serum interleukin-4 and gamma-interferon levels in the guinea pig with experimental allergic encephalomyelitis

BACKGROUND： Neuropeptide Y （NPY） may influence differentiation of Th cells immunological pathology of experimental allergic encephalomyelitis （EAE） is differentiation of Th cells It is assumed that the related to abnormal OBJECTIVE： To investigate the effect of NPY on white matter demyelination, the serum levels interleukin-4 （IL-4） and gamma-interferon （IFN-γ ）, as well as EAE pathogenesis in an EAE guinea pig model following NPY injection into the lateral cerebral ventricle. DESIGN, TIME AND SETTING： A randomized controlled animal study, which was performed in the Infection Immunity Animal Laboratory, Affiliated Hospital of Luzhou Medical College, China, from October 2005 to April 2006. MATERIALS： Thirty healthy female guinea pigs of 8-12 weeks of age, and 10 healthy female rats of three months of age were used. NPY was provided by Sigma Company, USA. NPY kit was provided by Beijing Huaying Biotechnology Institute, China. METHODS： Thirty guinea pigs were randomly divided into three groups： normal control group, EAE model group, and NPY intervention group （n =10 per group）. Normal control group and EAE model group： Saline （10μ L, once） was injected into the lateral cerebral ventricle. After one week, the same volume of Freund＇s adjuvant complete was either injected subcutaneously into two post-palms or EAE was modeled. NPY intervention group： EAE was modeled after one week and NPY was injected （10 μ L of 6 nmol NPY, once） into the lateral cerebral ventricle. Myelin basic protein （MBP） antigen made from rat spinal cord homogenate and Freund＇s adjuvant complete were injected subcutaneously into both post-palms （0.2 mL per palm） to establish the EAE model. MAIN OUTCOME MEASURES： White matter demyelination of the cerebrum, cerebellum, brain stem, and spinal cord were observed by light microscopy after HE staining. Levels of serum IFN-γ and IL-4 were detected by the double antibody sandwich ABC-ELISA technique. NPY content was detected by radioimmunoassay. RESULTS： Pathological alterations in the NPY intervention groups were reduced compared to those in the EAE model group, suggesting a reduction and remission of white matter demyelination with NPY treatment. When compared to the model group, the serum IL-4 level was increased in the NPY intervention group during the high-frequent EAE stage （P 〈 0.01）, but the serum IFN-γ level was decreased （P 〈 0.01）. Furthermore, the EAE latency was prolonged （P 〈 0.01）, the neurological scores were decreased in the high-frequent EAE stage （P 〈 0.01）, and the death rate was decreased （P 〈 0.05）. NPY content and the serum IL-4 level at the peak stage were positively correlated with those in the latent phase （r =0.863-0.900, P 〈 0.01）, but negatively correlated with neurological scores at the peak stage （r=- -0.068 to -0.863, P 〈 0.05-0.01）. The IFN-γ level at the peak stage was negatively correlated to that in the latent phase （r = -0.683-0.650, P 〈 0.05）, but positively correlated to neurological scores at the peak stage （r =0.975, 0.845, P 〈 0.05）. CONCLUSION： NPY injection into the lateral cerebral ventricle can promote the secretion of IL-4, inhibit the production of IFN-γ, relieve white matter demyelination, and inhibit EAE attack in an experimental model of EAE.

Effect of oxymatrine on interferon-gamma and tumor necrosis factor-alpha serum levels in an experimental rat model of autoimmune encephalomyelitis

BACKGROUND： Studies have demonstrated that experimental autoimmune encephalomyelitis （EAE） onset correlates with increased interferon-v （IFN-γ） and tumor necrosis factor-α （TNF-α） expression. Oxymatrine （OM） has been shown to inhibit autoimmune responses, but there are no reports showing that it could prevent the development of EAE. OBJECTIVE： To observe the effect of OM on serum levels of IFN-γ and TNF-α in a rat model of EAE.DESIGN, TIME AND SETTING： A randomized, controlled, animal study was performed at the Experimental Animal Center of Henan Academy of Chinese Medicine and at the Key Disciplines Laboratory Clinical Medicine of Henan Province between July and December 2008. MATERIALS： OM was purchased from Chia-tai Tianqing Pharmaceutical, China; complete Freund＇s adjuvant was purchased from Sigma, USA. METHODS： Forty female Wistar rats were randomly assigned to four groups： EAE model （M）, low-dose OM treatment （OM-L）, high-dose OM treatment （OM-H）, and normal control （N, no immunization）, with 10 rats in each group. EAE was established in the M, OM-L, and OM-H groups following immunization with Guinea pig spinal cord homogenate and complete Freund＇s adjuvant. The M and N groups were intraperitoneally injected with normal saline （6.7 mL/kg per day）, the OM-L group received an intraperitoneal injection of OM （100 mg/kg per day）, and the OM-H group received OM （150 mg/kg per day）. MAIN OUTCOME MEASURES： At 16 days after immunization, the degree of histopathological changes in the spinal cord was assessed by hematoxylin-eosin stanining. Enzyme-linked immunosorbent assay was used to detect serum levels of IFN-γ, and radioimmunoassay was utilized to determine serum TNF-α level. Neurological scores were measured on a daily basis according to a 0-5 scale. RESULTS： Daily injections of OM, both high and low doses, resulted in decreased neurological scores in EAE rats （P〈0.01）, as well as reduced cellular infiltration in the spinal cord and decreased levels of serum IFN-γ and TNF-α （P〈 0.01）. CONCLUSION： OM reduced the onset and severity of EAE, which correlated with decreased IFN-γ and TNF-α expression.