| ObjectiveParkinson`s disease (PD) is a common central nervous system de ge nerativedisease. Numerous studies have suggested that the transition element iron was closelyrelated to the development of PD[1]. It may activate free radicals, promote oxidativeinjury and cause cell into de ath by Iron abnormally increasing in brain, which islikely to be one of the factors contributing to neuronal death in neurode ge nerativediseases[2]. But the relationship between iron deposition and PD pathogenesis is farfrom clear. Previously, It was previously revealed in our lab that baicalin couldsignificantly alleviate iron accumulation while reduc ing the expression of DMT1andincreasing the expression of FP1of SN, which showed that baicalin had a protectiveeffect on nigrostriatal dopaminergic neurons. At the same time, in vitro, it was alsodemonstrated that baicalin could restrain iron accumulation by chelating with ironand controlling the expression of DMT1, FP1in cells. This project used BI to treatPD model rats, and observed iron content changes in different brain regions and invarious organs, detected DA in corpus striatum as well as its metabolic products,MDA, and the expression of TH, DMT1and FP1applying by IHC, ICP-AES, HPLCand Western Blot, et al.We researched the relationship be tween DA nerve injury of SN, iron depos itionand iron transport protein expression, understood the characteristics of irondistribution and accumulation in different brain regions and iron metabolism invarious organs. It also demonstrated that baicalin got influence on iron accumulation and iron metabolism of various organs. Finally we discussed the relationship betweeniron pathological disposition in brain and PD, and also discussed the mechanism ofbaicalin protection on DA and iron inhibition.METHOD84male Wistar rats except eleven for normal group stochastically (no treatment),The rotenone oily-emulision (2mg kg-1d-1) was injected subcutaneously to the backof the Wistar rats for4-6weeks to establish PD model. According to the behavioralscore system, the rats with scores2were selected and randomly divided into threegroups:①model group;②baicalin group;③deferoxamine group.⑴Observed therigidity and endurance of PD mode l by inclined plane test;⑵Observed changes ofcorpus striatum, TH of midbrain and DCX of SN and hippocampus by IHC.⑶Examined iron content variation of corpus striatum, hippocampus, substantia nigraand cerebellum by iron staining;⑷Detected the presentation of nissl body by nisslstaining;⑸Measured iron changes in SN, liver, kidney, heart and cerebellum of PDmod el rats by ICP–AES;⑹Detected MDA of cerebellum, heart, kidney, liver of PDmodel rats by enzyme linked immunosorbent assay;⑺Detected the content of DA,HVA, DOPAC in corpus striatum by HPLC.RESULTS1. The protection of Baicalin on dopaminergic neurons of the SN in PD ratsinduced by rotenone（1） As model being successful, It appeared significantly weight lose（P<0.01）;Resisting arrest behavior was weakened, piloerection, hair dirty, roachback,bradykinesia, initiative activity decrease, bradykinesia, tremor, instability ofgait. During2weeks after model being successfully, every performance described above all aggravating except piloerection. The whole ethologyactivity of PD mode l rats tended to be better in treating groups.（2）In inclined plane test: The sliding down times of model being successfully aswell as model at5and at8weeks were all more than normal group (P<0.01).Compared with model at5weeks group,The sliding down times significantlyinduced (P<0.01); Compared with model at8weeks group,The sliding downtimes still significantly changed (P<0.01);（3）The dopaminergic neurons in triatum and SN of model rats lost significantly(P<0.01); Both BI and DFO could reduce the loss of DA neurons in SN (TH-positive cells)(P<0.01) after8weeks treatment. It showed protection of BI andDFO on dopaminergic neurons of SN, while neither BI nor DFO got obviouslyTH staining changes of striatum（P>0.05）.（4）There was noobviously content changes of DA,HVA, DOPAC instriatum.（5）The IOD ofNissl staining in hippocampus significantly reduced compared withnormal（P＜0.01）; After BI and DFO8weeks treatment, The IOD of Nisslstaining in hippocampus significantly increased compared with mode（lP＜0.01或P＜0.05）.（6）The IOD of DCX staining in hippocampus significantly reduced compared withnormal（P＜0.01）; The IOD of DCX staining in SN obviously increasedcompared with normal（P＜0.01）. After BI and DFO treated for8weeks, theIOD of BI group in hippocampus significantly increased（P＜0.01）,while theIOD of DCX in DFO group had no marked variation. The IOD of DCX in SNof BI and DFO group significantly reduced（P＜0.01） 2. Baicalin alleviated iron accumulation in different brain regions rats and hadeffect on iron metabolic of various organs of Parkinson`s disease induced byrotenone（1）The positively-stained areas and the integral absorbance of iron staining in theglobus pallidus of the striatum, SN pars compacta, hippocampal dentate gyrusgranular layer, dentate-interpositus and facial nucleus of the cerebellum of PDrats were significantly increased compared with the normal control (P<0.01).The positive areas and integral absorbance of iron staining in the BI and DFOgroups treated for8weeks were both significantly reduced.(P <0.01).（2）Iron in liver was significantly increased compared with normal group (P<0.01),and iron in kidney was significantly decreased（P<0.05）；After8weekstreatment, iron in liver both BI and DFO group were significantly reduced (P <0.01or P <0.05), while there was no marked variation in kidney.（3）MDA detection obviously increased in model group (P<0.05), and there is nomarked variation in heart, kidney and cerebellum. After BI and DFO treatmentfor8weeks, there was no ob vious change s in the organs mentioned above.3. The effects of baicalin on iron desposition in SN and expression of proteinrelated to iron transport in PD rats induced by rotenone（1）Inductively coupled plasma atomic emission spectroscopy detected that iron inSN of the model group was significantly increased compared with normalgroup (P<0.05). After treatment for8weeks, iron content in BI and DFO groupsignificantly reduced (P <0.01).（2）The expression of DMT1in SN markedly increased (P＜0.01), and theexpression of FP1in SN obviously decreased model group compared withnormal group (P＜0.01); After8weeks treatment, the expression of DMT1 reduced significantly both in BI and DFO group (P＜0.01).FP1obviouslyincreased in DFO group(P＜0.05) while there was no marked variation in BIgroup.CONCLUSION(1) Iron significantly accumulated in the globus pallidus of the striatum, SN parscompacta, hippocampal dentate gyrus granular layer, dentate-interpositus andfacial nucleus of the cerebellum of PD rats induced by retonone, which stiil hasno reported about that. Iron content increased in liver and decreased in kidney, itpresented that iron etabolize disordered in various of organs. It has been clearrealized that dyskinesia of PD patients was one of the complex syndrome mainlycharacter with extrapyramidal dysfunction. Iron abnormal was probably not onlyinjuried in the substantia nigra dopaminergic system, but also in various brainregions. Thereby trigger degenerative diseases with brain nuc lei pathologicalchanges. It pointed out that Inhibition of iron accumulation might be a importantlinks on PD treatment(2) Inductively coupled plasma atomic emission spectroscopy detected that iron wassignificantly increased in SN of PD rats induced by retonone, which confirmedthe iron staining results. We synchronously found DMT1increasing and FP1decreasing,which demonstrated that DMT1and FP1participated in the occurrenceand develop ment of the iron accumulation in substantia nigra. And furtherpromoted the damage of DA nerve cell and the development of Parkinson’sdisease(3) BI could controll the expression of DMT1, a lleviate iron accumulation in differentbrain regions, reduce iron in liver to regulate iron metabo lism in various organsand decrease the death of cells, which probably one of the mechanisms for DA protection. Compared with BI, DFO also showed the function of DA protection,the expression of DMT1and FP1controlling and iron accumulation in SNreduction.(4) Iron deposition was restrained in the globus pallidus of the striatum, SN parscompacta, hippocampal dentate gyrus granular layer, dentate-interpositus andfacial nucleus of the cerebellum by BI and DFO. It could also reduce iron in liverin order to control iron metabolism in various organs. The result suggested thatthe pharmacology function of BI and DFO related with chelating iron in body.(5) Dopa mine neurons was obvi ously de ficiency in striatum and SN of PD modelinduced by retonone the Protection mechanism of DA neurons by BI and DFOwas mainly related to restain iron accumulation, and further restrain theexpresstion changes of DMT1a nd FP1. |
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