Flunarizine Affect Immunoreactivity Of Nigral Microglial And Dopaminergic Neurons And Relationship Of Them

IntroductionParkinsons disease (PD) is a usually devastating movement disorder characterized by selective degeneration of the nigrostriatal dopaminergic pathway . Degeneration of the nerve terminals in the substantia nigral leads to dopaminergic reduce . It be thinked that the dopaminergic neurons injury make microglial cells activation in the past years. Recent research has suggested the microglial activation play an important role in the dopaminergic neurons in the substantia nigra of PD. Microglial activation product a variety of proinflamniatory and neu-rotoxic factors damage to neurons. In order to study the change of nigral microglial and dopaminergic neurons. In our study we use a selective calcium channel blocker -flunarizine(Fz) injections to rats. The rats can emerge similar signs of PD. Such a novel neurotoxic action of Fz, we observe the change of nigral microglial and dopaminergic neurons immunoreactivity and relationship between them to announce that the damage of dopaminergic neurons be lie in the activated microglial. Microglial activation maybe promote the degeneration of dopaminergic neurons It provide a new pathogenesis to parkinsons disease.Materials and Method1. Make sectionMice of both sexes (150 -200gbwt)were injected with Fz (sigma,hydro-chloride salt dissolved in 1. 5% tartaric acid ) in trasperitoneally. Control ani-mals received 1.5% tartaric acid injections with dosages similar to the experimental groups. At various survival periods(1 day, lweek ,1 month) after Fz injections , the animals were transcardially perfused with 4% paraformaldehyde in 0.1 M phosphate buffer(PH7.4). Coronal sections were cut serially at 5 - um thickness on microtome for tyrosine hydroxylase(TH) , Monoclonal antibodies a-gainst the CR3 complement receptor (OX -42) , the poiyclonal anti - glial fi-brillary acidic protein( GFAP)2. Dyeingimmunohistochemistry sections get off candle to water. Following it is 3% H2O2 for lOmin to get off endogenous peroxidase activity. Use normal goat serum to treat it for 30 min at room temperature to reduce nonspecific staining after rinsing. Use primary antiserum at a low dilution ( TH: 1:500, Ox - 42 1:300, GFAP 1:200) , treat the control group with 0.1M PBS(PH7.4) instead of it at 4T!. After 12 hours, add the secondary antibody to attach to the primary antise-rum at 37^ for 30 min. After that is SABC fluid with the same conditions Then with DAB reaction for lOmin at dark place. Seal the section and observed by microscope.Results1. Flunarizine affect immunoreactivity of nigral dopaminergic neuronsOne day after Fz administration, TH - immunoreactive cells in the substan-tia nigral were drastically decreased in number as compared to the control. A loss of TH immunoreactivity was gradually recovered with time in both the drug treated of the control groups after a week. A Month after drug administration ,as mang as 90% of substantia nigra cells were immunoreactive to TH.Flunarizine affect immunoreactivity of nigral microglialNormal microglial cell body ic thin with thin enation, nucleu is small . One day after Fz administration, microglial is activated compared with contort, a significant portion of the microglial was larger in size than those control. One week after Fz administration, the quantity of microglial activation is reduced A month after Fz administration, as many as normal.Flunarizine affect immunoreactivity of astrocyteThe different periods (one day, a week, a month) , immunoreactivity of astrocyte is same as the control. There is no significant change of the shape and quantity of the cell.DiscussionFrom the study results we see; Injection Fz lead to nigral neurons injury, but this injury is reversible. Morphology observation;one day ofter Fz injection, microglial is activated in nigral, which shape is similar to phagocytin. At the same time the immunoreactivity of nigral dopaminergic neurons whole disappeared. One week after Fz injection, the quantity of microglial activation is reduced and the immunoreactivity of nigval dopaminergic neurons is recovered. A month after Fz injection both of them were recovered as same as the normal. The results show that microglial activation has been associated with the injury of DA neurons immunoreactivity Del - Hortega think that the density of nigral microglial is higher than other brain zone Kreutzberg think that microglial is sensor of nervous system As immune cells in the brain, microglial occupy 10% percent in whole cells. It play a important role in immune surveillance. When microenvi-ronment factor change, microglial can make a response quickly. From the resting shape to the activated shape with swallow function. The patients of PD is characterized by selective degeneration of the nigrostriatal dopaminergic pathway. A ctivated microglial secrete a variety of proinflammatory and cytotoxic factors such as the cytokines(TNF - a and IL -1(3 )and free radical NO and the reactive oxygen species (ROS) , which work on concert to induce neurodegenera-tion. The results show that activated microglial may be induce neurodegenera-tion. Through our study we can see Slowing the change of three Fz dose in different periods(24hr, a week a month) immunoreactivity of nigral microglial and dopaminergic neurons are difference Fz induces a transient depletion of dopa-mine in nigrostriatal neurons but leaves them viable. The dopamine content in these neurons is greatly reduced as rapidly as one day after Fz administration and there after recovered in both dose - and time - dependent fashion. It is show thatthe anti - dopaminergic action on Fz its antagonism against dopamine - induced inhibition of vasoconstriction. So deeply inquire into the relationship between microglial activation and PD, which provide new train of thought.ConclusionFz can actived microglial and lead to nigral DA neurons immunoreactivity reduce, which lead to DA neurons injury.Nigral microglial activation is closely related with nigral DA neurons immunoreactivity. Now that nigral microglial activation maybe an early event contributing to the degeneration of SN dopaminergic neurons.Taking Fz for a long time lead to nigral neurons injury, but the injury is reversible...