Neuronal nitric oxide synthase (nNOS) is constitutively expressed in neurons of the central nervous system, where it plays a physiological role in neurotransmission. In this study, we examined the functional role of nNOS in experimental autoimmune encephalomyelitis(EAE). The effects of the specific nNOS inhibitor 7-nitroindazole on normal and EAE rats were studied by immunohistochemistry and Western blot analysis. We found that nNOS is constitutively expressed in the spinal cords of normal rats, whilst in the spinal cords of EAE rats, nNOS expression slightly increased, concomitant with the infiltration of T cells and macrophages. Immunohistochemical studies showed that nNOS expression in macrophages and astrocytes increased at the peak stage of EAE and declined thereafter. Treatment with 7-nitroindazole (30 mg/kg) significantly delayed the onset of EAE paralysis, but had no effect on either the incidence or the severity of the paralysis. These findings suggest that nNOs inhibition has a limited role in the induction of rat EAE, and that constitutive nNOS in the spinal cord functions as a novel neurotransmitter, rather than a pro-inflammatory agent.
Animals ; Astrocytes/*enzymology ; Blotting, Western ; Encephalomyelitis, Autoimmune, Experimental/drug therapy/*enzymology ; Enzyme Inhibitors/therapeutic use ; Immunohistochemistry ; Indazoles/therapeutic use ; Macrophages/*enzymology ; Male ; Nitric Oxide Synthase/antagonists&inhibitors/*metabolism ; Rats ; Rats, Inbred Lew ; Spinal Cord/cytology/*enzymology

In order to investigate the role of heme oxygenase-1 (HO-1) in the molecular mechanism of experimental allergic encephalomyelitis (EAE), which was induced by guinea pig spinal cord homogenate + complete freund adjuvant on Wistar rats, we observed the gene of HO-1 and its protein expression with reverse transcriptase polymerase chain reaction(RT-PCR) and immunohistochemistry 1, 7, 14, and 21 d after EAE induction in rats. The relationship between HO-1 and the symptoms of EAE was also observed. The results showed that the levels of HO-1 mRNA and its protein expression were very low in the brains of the control group, whereas they were enhanced gradually with pathological course in the brain and onsets of symptoms, signs of EAE. On day 7, the level of HO-1 mRNA reached the peak, but the expression level of HO-1 protein in the brains reached the peak on day 14. The immunoreactive cells of HO-1 were mainly located at the choroid plexuses and subfornical organ (SFO), as well as in regions around the "sleeve-like" lesion foci, all of which were coincident with the locations of lesions of EAE. The levels of HO-1 mRNA and its protein expression were lowered gradually on day 21, which were in parallel with the severities of symptoms and signs of EAE. After a specific inhibitor of HO-1, Snpp-9, was applied, both of the symptoms and pathological lesions of EAE in the rat brains were mitigated markedly. Therefore, these results may suggest that the dynamic changes of HO-1 mRNA and its protein expression are in parallel with the changes of symptoms and pathological lesions of EAE in the brain. In conclusion, the levels of HO-1 mRNA and its protein expression in brains may play an important role in the pathogenesis of EAE, and application of inhibitors of HO-1 may be one of the potential therapeutic ways for the prevention and treatment of EAE.
Animals ; Brain ; enzymology ; metabolism ; Encephalomyelitis, Autoimmune, Experimental ; enzymology ; genetics ; physiopathology ; Female ; Heme Oxygenase (Decyclizing) ; biosynthesis ; genetics ; Heme Oxygenase-1 ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Wistar ; Subfornical Organ ; metabolism ; pathology

To elucidate the role of nitric oxide synthase (NOS) in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), we analyzed the expression of constitutive neuronal NOS (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS) in the spinal cords of rats with EAE. We further examined the structural interaction between apoptotic cells and spinal cord cells including neurons and astrocytes, which are potent cell types of nitric oxide (NO) production in the brain. Western blot analysis showed that three forms of NOS significantly increased in the spinal cords of rats at the peak stage of EAE, while small amounts of these enzymes were identified in the spinal cords of rats without EAE. Immunohistochemical study showed that the expression of either nNOS or eNOS increased in the brain cells including neurons and astrocytes during the peak and recovery stages of EAE, while the expression of iNOS was found mainly in the inflammatory macrophages in the perivascular EAE lesions. Double labeling showed that apoptotic cells had intimate contacts with either neurons or astrocytes, which are major cell types to express nNOS and eNOS constitutively. Our results suggest that the three NOS may play an important role in the recovery of EAE.
Animals ; Apoptosis ; Encephalomyelitis, Autoimmune, Experimental/*enzymology ; Endothelium, Vascular/enzymology ; Immunohistochemistry ; In Situ Nick-End Labeling ; Male ; Nitric Oxide Synthase/*metabolism ; Nitric Oxide Synthase Type I ; Nitric Oxide Synthase Type II ; Nitric Oxide Synthase Type III ; Rats ; Rats, Inbred Lew ; Spinal Cord/*enzymology/pathology

OBJECTIVETo study the effects of Zuogui Pill (, ZGP) and Yougui Pill (, YGP) on the expressions of brain-derived neurotrophic factor (BDNF) and cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling of axonal regeneration in the Lewis rats with experimental autoimmune encephalomyelitis (EAE), in order to explore the possible mechanism of ZGP and YGP on promoting axonal regeneration.

METHODSThe rats were randomly divided into normal control (NC), model (MO), prednisone acetate (PA), ZGP and YGP groups. The EAE model of rat was established by injecting antigen containing myelin basic protein (MBP)68-86. The brain and spinal cord were harvested on the 14th and 28th day post-immunization (PI), the protein and mRNA expression of BDNF and PKA in the brain and spinal cord of rats were detected by Western blot analysis and real-time quantitative polymerase chain reaction (PCR), and the cAMP levels were detected by using enzyme-immunoassay method.

RESULTS(1) On the 28th day PI, the mRNA expression of BDNF in brain white matter and spinal cord of rats in ZGP and YGP groups were up-regulated, especially in YGP group (P<0.05 or P<0.01). (2) On the 14th day PI, the cAMP levels in brain white matters significantly increased in PA and YGP groups compared with MO group (P<0.05 or P<0.01), and the cAMP level in YGP group was higher than that in ZGP group (P<0.05). The cAMP level in spinal cord also significantly increased in YGP group compared with MO, PA and ZGP groups, respectively (P<0.01). (3) On the 14th day PI, the PKA expression in spinal cord of rats in ZGP group was significantly decreased compared with MO and YGP groups, respectively (P<0.05). (4) On the 28th day PI, there was a positive correlation between cAMP and PKA expression in the brain white matter of YGP rats.

CONCLUSIONSThe results suggest that ZGP and YGP may promote axonal regeneration by modulating cAMP/PKA signal transduction pathway, but the targets of molecular mechanism of ZGP may be different from those of YGP.

Animals ; Axons ; drug effects ; pathology ; Brain ; drug effects ; metabolism ; pathology ; Brain-Derived Neurotrophic Factor ; genetics ; metabolism ; Cyclic AMP ; metabolism ; Cyclic AMP-Dependent Protein Kinases ; genetics ; metabolism ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Encephalomyelitis, Autoimmune, Experimental ; drug therapy ; enzymology ; genetics ; Female ; Gene Expression Regulation ; drug effects ; Nerve Regeneration ; drug effects ; genetics ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Inbred Lew ; Signal Transduction ; drug effects ; genetics ; Spinal Cord ; drug effects ; metabolism ; pathology ; Tablets