Effects of cotransplantated Schwann cells and neural stem cells in a rat model of Alzheimer's disease

Schwann cells （SCs） are significantly better at promoting neural stem cell （NSCs） proliferation, differentiation and synaptic formation when cocultured with NSCs in vitro, compared with cultured in a single nerve growth factor. The present study transplanted NSCs and SCs into the brain of a rat model of Alzheimer＇s disease to investigate the effect of cotransplantation. Results show transplantation of both NSCs alone and NSCs ＋ SCs significantly promoted learning and memory functions in Alzheimer＇s disease rats, decreased glial fibrillary acidic protein and calcium binding protein S100β expression, but increased expression of the cholinergic neuron marker choline acetyl transferase mRNA. The effect of NSCs ＋ SCs cotransplantation was, however, more significant. NSCs and SCs cotransplantation significantly reduced the number of astrocytes and increased cholinergic neurons, facilitating the recovery of learning and memory function, compared with NSCs transplantation alone.

Protective effects of transplanted neural stem cells on the brain of Alzheimer’s disease rats

BACKGROUND： To date, no drugs are able to halt the progression of Alzheimer＇s disease （AD）. Neural stem cells （NSCs） transplantation has been widely used to treat AD, but the mechanism of AD treatment remains unclear. OBJECTIVE： To observe changes in protein and factors in the hippocampus and frontal lobe of AD rats following NSCs transplantation, and to understand mechanism of action of NSCs transplantation in AD treatment. DESIGN, TIME AND SETTING： A randomized, controlled animal study was conducted at the First Clinical Hospital, Jilin University, China from July 2007 to March 2009. MATERIALS： NSCs were harvested from the hippocampus of 10 E16 Wistar rats. METHODS： A total of 57 male adult Wistar rats were equally and randomly divided into normal control, AD model and NSCs groups. AD models were established in the AD model and NSCs groups by bilateral removal of hippocampus. At 2 weeks postsurgery, NSCs were transplanted into the hippocampus of rats from the NSCs group. MAIN OUTCOME MEASURES： Protein levels were measured in the hippocampus of rats from normal control, NSCs and AD model groups using proteomics. Expression of choline acetyl transferase mRNA, glial fibrillary acidic protein and S100β was measured in the hippocampus and frontal lobe of rats using in situ hybridization and immunohistochemistry. RESULTS： Expression of choline acetyl transferase mRNA, heat shock protein 70, heat shock protein 90, F-actin and actin was significantly higher in the NSCs group compared with AD model group. Glial fibrillary acidic protein and S100β expression was less in the NSCs group compared with AD model group. CONCLUSlOIN： NSCs implanted into the brain may generate new neural cells, which can relieve damage to the cholinergic system and resist apoptosis. NSCs transplantation plays a protective role in the cholinergic system in the AD rats to some extent.

Tolerance of nestin^+ cholinergic neurons in the basal forebrain against colchicine-induced cytotoxicity

In the present study we injected colchicine into the lateral ventricle of Sprague-Dawley rats to investigate the effects of colchicine on the number of different-type neurons in the basal forebrain and to search for neurons resistant to injury. After colchicine injection, the number of nestin^＋ cholinergic neurons was decreased at 1 day, but increased at 3 days and peaked at 14-28 days. The quantity of nestincholinergic neurons, parvalbumin-positive neurons and choline acetyl transferase-positive neurons decreased gradually. Our results indicate that nestin^＋ cholinergic neurons possess better tolerance to colchicine-induced neurotoxicity.

Special function of nestin^+ neurons in the medial septum-diagonal band of Broca in adult rats

Nestin＋ neurons have been shown to express choline acetyltransferase （CHAT） in the medial septum-diagonal band of Broca in adult rats. This study explored the projection of nestin＋ neu-rons to the olfactory bulb and the time course of nestin＋ neurons in the medial septum-diagonal band of Broca in adult rats during injury recovery after olfactory nerve transection. This study observed that all nestin＋ neurons were double-labeled with ChAT in the medial septum-diagonal band of Broca. Approximately 53.6% of nestin~ neurons were projected to the olfactory bulb and co-labeled with fast blue. A large number of nestin~ neurons were not present in each region of the medial septum-diagonal band of Broca. Nestin＋ neurons in the medial septum and vertical limb of the diagonal band of Broca showed obvious compensatory function. The number of nestin＋ neurons decreased to a minimum later than nestin/CHAT＋ neurons in the medial sep- turn-diagonal band of Broca. The results suggest that nestin＋ cholinergic neurons may have a closer connection to olfactory bulb neurons. Nestin＋ cholinergic neurons may have a stronger tolerance to injury than Nestin/CHAT＋ neurons. The difference between nestin＋ and nestin-/ ChAT＋ neurons during the recovery process requires further investigations.

Impairment of cognitive function and reduced hippocampal cholinergic activity in a rat model of chronic intermittent hypoxia

The present study established a rat model of chronic intermittent hypoxia （CIH） to simulate obstructive sleep apnea syndrome. CIH rats were evaluated for cognitive function using the Morris water maze, and neuronal pathology in the hippocampus was observed using hematoxylin-eosin staining. In addition, hippocampal choline acetyl transferase （CHAT） and nicotinic acetylcholine receptor （nAChR） expression was determined by immunohistochemistry. Our results revealed necrotic hippocampal neurons, decreased ChAT and nAChR expression, as well as cognitive impairment in CIH rats. These results suggest that hippocampal neuronal necrosis and decreased cholinerqic activity may be involved in CIH-induced cognitive impairment in rats.

Effects of Naotan Pill on repair of neural cells and cognitive disorders in juvenile rats following hypoxia and ischemia

BACKGROUND： Hypoxia and ischemia induce neuronal damage, decreased neuronal numbers and synaptophysin levels, and deficits in learning and memory functions. Previous studies have shown that lycium barbarum polysaccharide, the most effective component of barbary wolfberry fruit, has protective effects on neural cells in hypoxia-ischemia. OBJECTIVE： To investigate the effects of Naotan Pill on glutamate-treated neural cells and on cognitive function in juvenile rats following hypoxia-ischemia. DESIGN, TIME AND SETTING： The randomized, controlled, in vivo study was performed at the Cell Laboratory of Lanzhou University, Lanzhou Institute of Modern Physics of Chinese Academy of Sciences, and Department of Traditional Chinese Medicine of Gansu Provincial Rehabilitation Center Hospital, China from December 2005 to August 2006. The cellular neurobiology, in vitro experiment was conducted at the Institute of Human Anatomy, Histology, Embryology and Neuroscience, School of Basic Medical Sciences, Lanzhou University, and Department of Traditional Chinese Medicine of Gansu Provincial Rehabilitation Center Hospital, China from March 2007 to January 2008. MATERIALS： Naotan Pill, composed of barbary wolfberry fruit, danshen root, grassleaf sweetflag rhizome, and glossy privet fruit, was prepared by Gansu Provincial Rehabilitation Center, China. Rabbit anti-synaptophysin, choline acetyl transferase polyclonal antibody, streptavidin-biotin complex kit and diaminobenzidine kit （Boster, Wuhan, China）, as well as glutamate （Hualian, Shanghai, China） were used in this study. METHODS： Cortical neural cells were isolated from neonatal Wistar rats. Neural cell damage models were induced using glutamate, and administered Naotan Pill prior to and following damage. A total of 54 juvenile Wistar rats were equally and randomly assigned into model, Naotan Pill, and sham operation groups. The left common carotid artery was ligated, and then rat models of hypoxic-ischemic injury were assigned to the model and Naotan Pill groups. At 2 days following model induction, rats in the Naotan Pill group were administered Naotan Pillsuspension for 21 days. In the model and sham operation groups, rats received an equal volume of saline. MAIN OUTCOME MEASURES： Neural cell morphology was observed using an inverted phase contrast microscope. Survival rate of neural cells was measured by MTT assay. Synaptophysin and choline acetyl transferase expression was observed in the hippocampal CA1 region of juvenile rats using immunohistochemistry. Cognitive function was tested by the Morris water maze. RESULTS： Pathological changes were detected in glutamate-treated neural cells. Neural cell morphology remained normal after Naotan Pill intervention. Absorbance and survival rate of neural cells were significantly greater following Naotan Pill intervention, compared to glutamate-treated neural cells （P 〈 0.05）. Synaptophysin and choline acetyl transferase expression was lowest in the hippocampal CA1 region in the model group and highest in the sham operation group. Significant differences among groups were observed （P 〈 0.05）. Escape latency and swimming distance were significantly longer in the model group compared to the Naotan Pill group （P 〈 0.05）. CONCLUSION： Naotan Pill exhibited protective and repair effects on glutamate-treated neural cells. Naotan Pill upregulated synaptophysin and choline acetyl transferase expression in the hippocampus and improved cognitive function in rats following hypoxia-ischemia.

Therapeutic Benefit of Yangxue Qingnao Granule(养血清脑颗粒)on Cognitive Impairment Induced by Chronic Cerebral Hypoperfusion in Rats

Objective：To observe the therapeutic effect of Yangxue Qingnao Granule（养血清脑颗粒, YXQNG） on cognitive impairment induced by chronic cerebral hypoperfusion and to investigate its impact on oxidative stress,apoptosis,and the cholinergic system.Methods：Adult male Wistar rats were subjected to chronic cerebral hypoperfusion by permanent occlusion of bilateral common carotid arteries（2-VO）.Thirty rats were randomly assigned to one of the five treatment groups in a 1：1：1：1：1 ratio：sham operation plus normal saline treatment,2-VO plus normal saline treatment,2-VO plus YXQNG at a dose of 2 g·kg（-1）·d^（-1） or 4 g·kg（-1）·d^（-1）, or 2-VO plus rivastigmine 2 mgkg^（-1）·d^（-1）.The Morris water maze test was used to assess the spatial memory retrieval.Apoptosis,total antioxide capacity（T-AOC）,acetylcholine esterase（AchE） and choline acetyl transferase（ChAT） activities in the hippocampus and the cortex were investigated.Results：In the chronic cerebral hypoperfusion model,the 2-VO plus saline treatment resulted in impaired special learning as shown by the significantly prolonged escape latency and shorter swim time in the first quadrant as compared to the sham operation.The impairment was associated with apoptosis and significant decreases in T-AOC,AchE and ChAT activities in the hippocampus and the cortex.Treatment with YXQNG at either 2 g·kg（-1）·d^（-1） or 4 g·kg（-1）·d^（-1） dose,or rivastigmine resulted in significantly shorter escape latencies and longer swim time in the first quadrant.YXQNG at both doses,but not rivastigmine,had significant reduction in apoptosis,and significant increases in T-AOC and ChAT activity in both the hippocampus and the cortex.Unlike rivastigmine,neither dose of YXQNG showed significant reduction in AchE activity.Conclusions：YXQNG ameliorated cognitive impairment induced by chronic cerebral hypoperfusion.The protective effect may be mediated through its regulation of apoptosis and activities of T-AOC and ChAT in the hippocampus and cortex of the rats in the chronic cerebral hypoperfusion model,a mechanism that is different from rivastigmine.

Effect of Methyl Jasmonic Acid on Baccatin Ⅲ Biosynthesis

As baccatin Ⅲ is an immediate diterpenoid precursor of taxol, the increase of baccatin Ⅲ is beneficial to the biosynthesis of taxol. Addition of methyl jasmonic acid （M J） enhances the activity of 10- deaceyle baccatin （DAB） iii acetyl transferase which catalyzes the bioconversion from 10-DAB Ⅲ to beccatin Ⅲ. In this paper, the baccatin Ⅲ content was increased by 174% by the addition of 100 IJmol/L MJ in suspension cultures of Taxus cuspidate. Induction by MJ also increased the expression of a 49.0-kDa protein. This paper describes the cell free acetylation of 10-DAB Ⅲ in crude extracts of enzyme from the suspension cultures of Taxus cuspidate. The reaction product was confirmed by high performance liquid chromatograph （HPLC）. About 25.0% of the 10-DAB Ⅲ was acetylized into baccatin Ⅲ on the 4th day with 100 IJmol/L MJ. The 10-DAB Ⅲ acetyl transferase activity reached a peak on the 2nd day with 100 μmol/L MJ, with 54.7% of the 10-DAB Ⅲ transformed into baccatin Ⅲ. The baccatin Ⅲ content increased with the increase of 10-DAB Ⅲ acetyl transferase activity, although the biosynthesis was delayed by more than 24 h. The remarkable induction of MJ on baccatin Ⅲ biosynthesis shows a promising way to increase the production of taxol.