| Objective Incidence of major depressive disorder is rising with highincidence, recurrence rate and dangerous. According to the statistics ofWHO, two-thirds of the patients attempt suicide and ultimately15%of thepatients commit suicide.The mortality is20times that of the generalpopulation. In each year, about287000people died of suicide in China.By2020, increasing social and economic burden of depression may be secondonly to heart disease, the second largest disease which is threaten humanhealth seriously. So the pathogenesis and treatment of depression have beena hot spot of research. What the brain or telencephalon is directlyconnected with the outside world by olfactory pathway reveals the smellis closely correlation of the brain. Smell is immediately involved inemotion management function of the amygdala. Meanwhile,smell have alsomanaged cingulate cortex, hippocampus, papillae, septal nuclei, basalforebrain and hypothalamus of the edge structure. A growing number ofstudies show that olfactory pathway is considered to be regulate mood, andthey are also important part of the brain function. On the otherhand,decreased neurogenesis of the limbic system has been considered asan eventual pathway of depression. Therefore,prevention and cure of nervemental diseases by olfactory pathways may be a new way. This research isdesigned to explore and evaluate the effects of vanillin inhalation ondepression-like behaviors and the underlying mechanisms,such as expression of BDNF in the brain and the level of serum magnesium.Part One Establish the Depression Animal ModelMethods Depression animal model is established by chronic unpredictablemedium stress combined with isolation.At the same time,in order to identify thepathway by which vanillin worked, another two groups were added: the olfactorybulbectomy+vanillin group (OBX) and the sham group (Sham).Results Compared with pre-model, after CUMS procedure, body weight of animalswas decreased significantly（P<0.01）;the immobility time (IT) in forcedswimming test (FST) was increased （P<0.01）while sucrose water consumption(SWC) was significantly decreased （P<0.01）;the crossing and rearing inopen field test (OFT) was also decreased significantly （P<0.01).Comparedwith the Sham group,the weight and SWC of OBX group was significantlydecreased while the IT in FST was increased（P<0.01or P<0.05）.The OFTwas no significant between the two groups. When come to serum cortisol,serumcortisol after CUMS and OBX has significantly increased compared withnormal rats(P<0.05).Part Two: The Observation of Neuroethology of CUMS and OBX Group afterVanillin InterventionMethods The depressed rats were divided randomly into vanillin inhalationgroup,fluoxetine hydrochloride group,depression model group,olfactorybulbectomy with the vanillin inhaled treatment,sham group.Nervous behavioral changes has been observed at different time spots after theadministration of5weeks.Results Compared with the post-model:In vanillin group, the IT in FST wassignificantly decreased （P<0.05） after2W treatment,and the volume ofsucrose water consumption was significantly increased （P<0.05）; theweight was significantly increased (P<0.05）after3W;the crossing andrearing in open field test (OFT) after5W was also increased significantly（P<0.05）. In fluoxetine hydrochloride group, the IT in FST wassignificantly decreased （P<0.05） after2W treatment, and the weight wassignificantly grew （P<0.05）after3W, and the volume of sucrose waterconsumption was significantly increased （P<0.05）after4W,and the crossingand rearing in OFT after5W was also increased significantly （P<0.05）;Inmodel group, there was no obvious change. In OBX group, there was noobvious change on the weight and the IT of FST and the volume of sucrosewater consumption after5W administration.However, both the the crossingand rearing in OFT after2W treatment were decreased significantly（P<0.01）.Part Three: The Influence on Brain Homogenate BDNF and Serum Magnesiumof Vanillin InhalationMethods First, the blood and the brain samples of the SD rats afteradministration were collected.Then, the serum magnesium and BDNF weredetected respectively by the way of biochemistry:ELISA andimmunohistochemistry. Results①The serum magnesium of vanillin group was greatly increasedcompared with model group（P<0.05）.When compared with the OBX group,similarresult was obtained.②BDNF/pr of the brain homogenate in vanillin group was significantlyincreased compared with model group (P<0.01）. When compared with the OBXgroup,similar result was obtained.③Immunohistochemistry and the average density of image analysis revealedthat the expression of BNDF of hippocampal CA3and amygdala area in vanillingroup was significantly increased （P<0.01）.Conclusions①The olfactory is closely related to depression.Olfactorybulbectomy can lead to depression-like behaviors in rats.②Vanillin inhalation significantly relieves depression-like behaviors indepression rats.The possible mechanism is that raised serum magnesium andBDNF in brain homogenate which increases hippocampal neurogenesis andmodulates function of brain areas. |
PDF Full Text Request