OBJECTIVETo study whether apoptosis plays a role in controlling the number of olfactory receptor neurons, so as to reveal the specialty and mystery of neurogenesis.

METHODSUsing terminal deoxynucleotidyl transferase-mediated dUTP-fluorescein nick end labeling (TUNEL) and transmission electron microscopy to detect apoptosis in olfactory mucosa of normal adult rats and damaged olfactory mucosa of 16, 32, 48 hours and 3, 7, 30 days after bulbectomy.

RESULTSIn normal olfactory epithelium, a subpopulation of immature neurons, as well as mature neurons, showed internucleosomal DNA-fragmentation. The number of TUNEL-labeled neurons increased dramatically 32 hours after removal of olfactory bulb. Then it declined quickly and remained at low level. Ultrastructural data of olfactory mucosa showed that the feature of apoptotic neurons was chromatin condensation and cell shrinkage. Besides, some dying cells were characterized by the formation of numerous autophagic vacuoles, and few had some of the features of necrosis but without obvious mitochondrial swelling.

CONCLUSIONSApoptosis might play a role in turnover of the olfactory epithelium and regeneration in adult rats. There might be other two types of neural death through different mechanism.

Animals ; Apoptosis ; Male ; Olfactory Bulb ; surgery ; Olfactory Mucosa ; cytology ; pathology ; Olfactory Receptor Neurons ; cytology ; Postoperative Period ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To observe the olfactory bulb's morphological change after ischemic injury in rats, and explore the role of vascular factor in olfactory disorders. METHOD: Forty adult SD rats (weighting 250-300 g) were used, 30 of which were treated with permanent bilateral occlusion of both common carotid arteries, and the others were served as the control. The olfactory bulbs were carefully taken out on the 1st week, 4th week, 2nd month post operation, respectively, then observed the morphological changes by light microscopy. The ultra structure of cells in olfactory bulbs were also observed by transmission electron microscope. RESULT: In rats with permanent bilateral occlusion of both common carotid arteries, the vascular pattern changed and the cell number decreased in olfactory bulbs by light microscopy. In the 1st week group, the mitral cells' mitochondria injury and metamorphism were found. In the 4th week group, the microvascular paramorphia, lipofuscin in mitral cells and metamorphic nerve fibers were found by transmission electron microscope. CONCLUSION Ischemia could injure the neuron and nerve fiber. This may be one of the reasons of olfactory disorders.
Animals ; Ischemia ; pathology ; Microscopy, Electron, Transmission ; Neurons ; pathology ; ultrastructure ; Olfactory Bulb ; cytology ; pathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo analyze the correlation between olfactory bulb (OB) volume, depth of olfactory sulcus (OS) and olfactory function in patients with olfactory dysfunction after upper respiratory tract infection.

METHODSOne hundred patients with olfactory dysfunction after upper respiratory tract infection (patient group) were compared with one hundred normal controls in terms of olfactory function T&T testing, OB volume and depth of OS assessed with magnetic resonance imaging (MRI). T&T testing and MRI were performed again after a year in patient group and the results were compared. SPSS 13.0 software was used to analyze the data.

RESULTST&T olfactory testing revealed that the patient group had higher scores than controls (t = 4.014, P < 0.05). Both men and women in patient group were affected by the same extent of olfactory loss (t value was 0.892, P > 0.05). Both men and women in control group were affected by the same extent of olfactory loss (t value was 1.011, P > 0.05). OB volume of left side in patient group was (38.14 ± 4.31) mm³, right side was (38.72 ± 4.22) mm³, average OB volume was (38.47 ± 4.27) mm³; OB volume of left side in controls was (51.65 ± 6.30) mm³, right side was (51.98 ± 6.34) mm³, average OB volume was (51.81 ± 6.32) mm³; OB volume was lower in patient group as compared with controls (t value were 4.233, 4.267 and 4.249, all P < 0.01). OS depth study revealed no statistical difference between patient group and control group (t value were 0.901, 0.948 and 0.927, all P > 0.05). Olfactory discriminate threshold was negatively correlated with OB volume in patient group and control group (r value were -0.598, -0.512, both P < 0.05) Olfactory discriminate threshold was not correlated with the depth of OS (r value were -0.152, -0.174, both P > 0.05). Olfactory discriminate threshold and OB volume were not correlated with the persistent time of the dysosmia in patient group (r value were -0.121, 0.139, both P > 0.05). Among 100 olfactory dysfunction patients after upper respiratory tract infection, when followed-up, 24 showed increased in OB volume and olfactory function after a year, but no statistical difference was found with the first time (t value were 0.894, 0.914, 0.942 and 0.931, all P > 0.05). The other 76 patients showed no significant changes of OB volume and olfactory function.

CONCLUSIONSThe OB volume was lower in patient group as compared with normal controls, the depth of OS showed no significant changes in patient group. The OB volume was correlated with olfactory function, the depth of OS was not correlated with olfactory function; Olfactory function had not correlated with the persistent time of the dysosmia in patient group.

Female ; Humans ; Magnetic Resonance Imaging ; Male ; Olfaction Disorders ; diagnosis ; Olfactory Bulb ; pathology ; Prefrontal Cortex ; pathology ; Respiratory Tract Infections ; physiopathology

OBJECTIVE: To explore the olfactory abilities in patients with allergic rhinitis (AR), analyze the correlation between olfactory bulb (OB) volume with depth of olfactory sulcus (OS) and olfactory function in patients with AR. METHOD: One hundred patients with AR were compared with one hundred controls in terms of olfactory function T&T testing, OB volume and depth of OS assessed with magnetic resonance imaging (MRI). T&T testing and MRI were done after a year in 100 AR patients,the results were compared with the initial results. RESULT: The OB volume in AR patients was (29.53±3.95) mm3 on the left, (29.67±14.21)mm3 on the right, (29.61±4.05) mm3 on average; The OB volume in controls was (48.93±6.73)mm3 on the left side, (48.81±7.43)mm3 on the right side, (48.85±7.11)mm3 on average; The OB volume in AR patients was less then the control group(t= 6.321, 6.141, 6.221, P<0.01). The OS depth had no statistical difference between AR patients and controls (t=1.032, 0.972, 0.991, P>0.05). Olfactory discriminate threshold was negatively correlated with OB volume in AR patients (r=-0.46, P<0.05); and it was no correlated with depth of OS (r=-0.012,P>0.05). Among 100 followed-up AR patients, 43 showed increased in OB volume and olfactory function after a year, but there was no statistical difference (t= 0. 811,0. 843, 0.826, P>0.05; Z=1.911, P>0.05) ,and the other 57 showed no significant changes of OB volume and olfactory function. CONCLUSION In AR patients, the OB volume and olfactory function decreased, but the depth of OS had no significant changes. The OB volume is correlated with olfactory function, while the depth of OS is no correlated with olfactory function. Conservative treatment had some clinical significance on the recovery of olfactory function in patients with AR.
Humans ; Magnetic Resonance Imaging ; Olfaction Disorders ; etiology ; Olfactory Bulb ; pathology ; physiopathology ; Prefrontal Cortex ; Rhinitis, Allergic ; complications ; Smell

Four small breed dogs were admitted with seizures. Magnetic resonance imaging (MRI) of the brain revealed dilation of the olfactory bulb cavity as well as enlargement of the lateral ventricles. These findings demonstrate that dilation of the olfactory bulb cavity can occur concurrent with hydrocephalus. This is the first description of the clinical and MRI features of dilation of the olfactory bulb cavity concurrent with hydrocephalus in dogs.
Animals ; Dilatation, Pathologic/veterinary ; Dog Diseases/*pathology ; Dogs ; Female ; Hydrocephalus/complications/pathology/*veterinary ; Magnetic Resonance Imaging/veterinary ; Male ; Olfactory Bulb/*pathology ; Seizures/pathology/veterinary

We investigated a topographical distribution of managanese, and immunohistochemical density of tyrosine hydroxylase (TH), and histopathologic findings in globus pallidus and substantia nigra according to manganese dose and time course in the brain of rats which received MnCl2 intravenously. Topographical distribution of manganese was also investigated after injection of FeCl2. The manganese concentrations of brain in control and experimental group were highest in pituitary gland and thalamus, and lowest in the cerebral cortex. The manganese concentration of blood was increased proportionally to the dose administered, and the biological half-life of blood manganese was between 21 and 42 days. The manganese concentrations of brain were increased proportionally to the dose, and increase rate was highest in olfactory bulb, and the biological half-lives of brain manganese ranged from 42 days to 90 or more days; the longest were observed in pituitary gland, medulla oblongata and cerebral cortex. In case of administration of FeCl2, the manganese concentrations of brain were higher than that of control group in dose of 2.5 mg/kg, and decreased proportionally to the administered dose, resulting in lower level compared with control group in high dose of FeCl2 administered. Significantly decreased number of nerve cell and increased gliosis in globus pallidus were observed in experimental group, which were closely correlated with the duration after manganese injection, but no significant change of number of nerve cell expressing TH and gliosis were observed in substantia nigra. Density of immunohistochemical reaction for TH in globus pallidus made little difference between control and experimental group. These results suggest that pathology of manganese intoxication is caused by the loss of nerve cells in globus pallidus, and closely correlated with the duration after manganese exposure.
Animals ; Brain* ; Cerebral Cortex ; Gliosis ; Globus Pallidus ; Half-Life ; Manganese* ; Medulla Oblongata ; Neurons ; Olfactory Bulb ; Pathology ; Pituitary Gland ; Rats* ; Substantia Nigra ; Thalamus ; Tyrosine 3-Monooxygenase

Parkinson's disease (PD) is a common neurodegenerative disorder arising from an interplay between genetic and environmental risk factors. Studies have suggested that the pathological hallmarks of intraneuronal α-synuclein aggregations may start from the olfactory bulb and the enteric nervous system of the gut and later propagate to the brain via the olfactory tract and the vagus nerve. This hypothesis correlates well with clinical symptoms, such as constipation, that may develop up to 20 years before the onset of PD motor symptoms. Recent interest in the gut–brain axis has led to vigorous research into the gastrointestinal pathology and gut microbiota changes in patients with PD. In this review, we provide current clinical and pathological evidence of gut involvement in PD by summarizing the changes in gut microbiota composition and gut inflammation associated with its pathogenesis.
Brain ; Constipation ; Enteric Nervous System ; Gastrointestinal Microbiome ; Humans ; Inflammation ; Microbiota ; Neurodegenerative Diseases ; Olfactory Bulb ; Parkinson Disease ; Pathology ; Risk Factors ; Vagus Nerve

Objective: To investigate the effects of dopamine on olfactory function and inflammatory injury of olfactory bulb in mice with allergic rhinitis (AR). Methods: AR mouse model was established by using ovalbumin (OVA), and the mice were divided into two groups: olfactory dysfunction (OD) group and without OD group through buried food pellet test (BFPT). The OD mice were randomly divided into 2 groups, and OVA combined with dopamine (3, 6, 9 and 12 days, respectively) or OVA combined with an equal amount of PBS (the same treatment time) was administered nasally. The olfactory function of mice was evaluated by BFPT. The number of eosinophils and goblet cells in the nasal mucosa were detected by HE and PAS staining. Western blotting, immunohistochemistry or immunofluorescence were used to detect the expression of olfactory marker protein (OMP) in olfactory epithelium, the important rate-limiting enzyme tyrosine hydroxylase (TH) of dopamine, and the marker proteins glial fibrillary acidic protein (GFAP) and CD11b of glial cell in the olfactory bulb. TUNEL staining was used to detect the damage of the olfactory bulb. SPSS 26.0 software was used for statistical analysis. Results: AR mice with OD had AR pathological characteristics. Compared with AR mice without OD, the expression of OMP in olfactory epithelium of AR mice with OD was reduced (F=26.09, P<0.05), the expression of GFAP and CD11b in the olfactory bulb was increased (F value was 38.95 and 71.71, respectively, both P<0.05), and the expression of TH in the olfactory bulb was decreased (F=77.00, P<0.05). Nasal administration of dopamine could shorten the time of food globule detection in mice to a certain extent, down-regulate the expression of GFAP and CD11b in the olfactory bulb (F value was 6.55 and 46.11, respectively, both P<0.05), and reduce the number of apoptotic cells in the olfactory bulb (F=25.64, P<0.05). But dopamine had no significant effect on the number of eosinophils and goblet cells in nasal mucosa (F value was 36.26 and 19.38, respectively, both P>0.05), and had no significant effect on the expression of OMP in the olfactory epithelium (F=55.27, P>0.05). Conclusion: Dopamine can improve olfactory function in mice with AR to a certain extent, possibly because of inhibiting the activation of glial cells in olfactory bulb and reducing the apoptotic injury of olfactory bulb cells.
Animals ; Disease Models, Animal ; Dopamine ; Humans ; Mice ; Mice, Inbred BALB C ; Nasal Mucosa/metabolism* ; Olfactory Bulb/pathology* ; Ovalbumin ; Rhinitis, Allergic/metabolism*

OBJECTIVETo investigate the effects of formaldehyde inhalation on the morphological damage, and Glu, GABA and NOS contents in olfactory bulb and hippocampus of rats.

METHODSTwenty SD rats were equally divided into two groups: rats in the control group inhaled fresh air, while the animals in experimental group were exposed to the air containing formaldehyde (12.5 mg/m(3), 4 h/d) for 7 days. Then rats were sacrificed and frozen sections of olfactory bulb and hippocampus were prepared. The morphological changes were examined and the Glu, GABA and NOS contents were detected using Nissl-staining, immunohistochemistry and Western blot, respectively.

RESULTCompared with the control group, there was a significant confusion and shrink of neuron morphology in experimental group, the number and staining intensity of Glu and NOS positive cells and protein contents were reduced. The protein expression of GABA was also decreased in the formaldehyde group.

CONCLUSIONFormaldehyde inhalation can cause a severe morphological damage of olfactory bulb and hippocampus in SD rats,which may further impair memory and learning ability through the reduction of Glu, GABA and NOS expression.

Animals ; Formaldehyde ; toxicity ; Glutamic Acid ; metabolism ; Hippocampus ; drug effects ; metabolism ; pathology ; Inhalation Exposure ; Learning ; drug effects ; Neurons ; drug effects ; metabolism ; pathology ; Nitric Oxide Synthase ; metabolism ; Olfactory Bulb ; drug effects ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley ; gamma-Aminobutyric Acid ; metabolism

OBJECTIVETo confirmed reliability and feasibility of intranasal nerve growth factor (NGF) bypassing the blood-brain barrier and its potential neuroprotective effects on acute cerebral ischemia.

METHODS(1) To assay NGF concentrations in different brain regions after middle cerebral artery occlusion (MCAO). Rats were randomly divided into intranasal (i.n.) NGF, intravenous (i.v.) NGF, and untreated group (n = 4). The concentrations of NGF of different brain regions in the three groups after MCAO were measured by ELISA. (2) To observe neuroprotective action of NGF on focal cerebral ischemic damage. Rats were randomly assigned to 4 groups: i.n. vehicle, i.n. NGF, i.v. vehicle, i.v. NGF (n = 8). Treatment was initiated 30 minutes after onset of MCAO and given again 24 hours later. Three neurologic behavioral tests were performed 24 and 48 hours following onset of MCAO. Corrected infarct volumes were determined 48 hours after onset of MCAO.

RESULTSThe olfactory bulb in i.n. NGF group obtained the highest concentration (3252 pg/g) of NGF among all regions, followed by the hippocampus. The NGF concentrations in the olfactory bulb and hippocampus in i.n. NGF group were markedly higher than that in i.v. NGF and control groups. The infarct volume in i.n. NGF group was markedly reduced by 38.8% compared with i.n. vehicle group. I.n. NGF group vestibulum function markedly improved compared with i.n. vehicle group at 24 and 48 hours after onset of MCAO (P24h = 0.02 and P48h = 0.04, respectively).

CONCLUSIONIntranasal NGF could pass through the blood-brain barrier, reach the central nervous system, reduce infarct volume, and improve neurologic function in rats following MCAO. Intranasal delivery of NGF may be a promising treatment for stroke.

Administration, Intranasal ; Animals ; Behavior, Animal ; drug effects ; Blood-Brain Barrier ; Brain ; metabolism ; pathology ; Hippocampus ; metabolism ; Infarction, Middle Cerebral Artery ; metabolism ; pathology ; Injections, Intravenous ; Male ; Nerve Growth Factor ; metabolism ; pharmacology ; Neuroprotective Agents ; pharmacology ; Olfactory Bulb ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley