Oxidative damage of primary cultured hippocampal neurons Does androgen have an antagonistic effect?

BACKGROUND: Evidence illustrates that androgen has a neuroprotective role.However,whether androgen also has the protective effect on hippocampal neurons during free radical mediated injury remains unclear.OBJECTIVE: To investigate the neuroprotective effect of androgen on hippocampal neurons during free radical damage.DESIGN,TIME AND SETTING: A controlled in vitro experiment was performed at the Department of Human Anatomy,Cell Culture Lab,and Neuroendocrinology Lab,Basic Medical School,Hebei Medical University from February to June 2009.MATERIALS: Testosterone was provided by Tianjin Jinyao Amino Acid Company,China.METHODS: Primary cultured neurons from 24 Sprague Dawley rats were randomly assigned into four groups: control,H2O2,testosterone,and testosterone (pre-added) plus H2O2 groups.MAIN OUTCOME MEASURES: The positive cell ratio of microtubule associated protein-II and neuron specific enolase was determined by immunocytochemistry.Neuronal morphology was observed by hematoxylin-eosin staining and Nissl staining.Cell vitality and viability were determined using an inverted phase contrast microscope.The content of nitric oxide synthase,malondialdehyde,and superoxide dismutase were measured with a spectrophotometer.RESULTS: As compared with the control group,cell vitality and viability,and superoxide dismutase level were significantly decreased in the H2O2 group (P < 0.05),while nitric oxide synthase and malondialdehyde levels were significantly increased (P < 0.05).Neuronal vitality and viability as well as superoxide dismutase level in the testosterone plus H2O2 group were significantly greater than in the H2O2 group (P < 0.05),and nitric oxide synthase and malondialdehyde levels were significantly less than in the H2O2 group (P < 0.05).CONCLUSION: Androgen partially reversed H2O2-induced neuronal damage and protected neurons.

Influence of leptin on luteinizing hormone and follicle stimulating hormone secreted from cultured rat anterior pituitary cells

BACKGROUND: Leptin may regulate reproductive function via release of hypothalamic neuropeptide Y. However, it is unknown whether this regulatory effect is limited to the hypothalamus. OBJECTIVE: To detect the effect of different dosages of leptin on luteinizing hormone (LH) and follicle stimulating hormone (FSH) secretion from in vitro cultured rat anterior pituitary cells. DESIGN: Contrast study based on cells. SETTING: This study was performed in the Basic Institute of Chengde Medical College, Chengde City, Hebei Province, China from March to June 2007. MATERIALS: Eighteen female Wistar rats of three months of age, weighing 200-220 g, and of clean grade were used. Leptin was provided by Peprotech Company, DMEM culture medium by Invitrogen Company, and the radioimmunological kit by Beijing Zhongshan Jinqiao Biotechnology Co., Ltd. METHODS: Three glandular organs were regarded as one group for culture of anterior pituitary cells. In the control group, saline was added to the culture medium instead of leptin. In the leptin group, leptin was prepared into different concentrations of 1×10-12, 1×10-11, 1×10-9, 1×10-7, and 1×10-6 mol/L for stimulation of cultured cells. The culture supernatant was obtained at three hours after additional of saline/leptin. MAIN OUTCOME MEASURES: Contents of LH and FSH were detected by radioimmunology. RESULTS: Following leptin stimulation, LH release increased with increasing concentrations of leptin up to 1×10-9 mol/L, where LH release peaked. LH release then progressively decreased with increasing leptin concentrations (P < 0.01). LH release in the leptin (1×10-12, 1×10-11, 1×10-7, and 1×10-6 mol/L) groups was significantly higher than that in the control group (P < 0.01). FSH content in the leptin (1×10-11, 1×10-9, and 1×10-7 mol/L) groups was significantly higher than that in the control group (P < 0.01). CONCLUSION: Leptin can directly affect pituitary tissue to promote the secretion of LH and FSH in a dose-dependent manner.

Intracerebroventricular leptin injection affects neuroendocrine reproductive axis in ovariectomized rats

BACKGROUND:Leptin regulates neuroendocrine function of the hypothalamus-pituitary-ovary axis in humans. OBJECTIVE: To verify effects of intracerebroventricular leptin injection on neuroendocrine function of the hypothalamus-pituitary-ovary axis in ovariectomized rats. DESIGN, TIME AND SETTING: A randomized, controlled experiment was performed at the Basic Medical Institute, Chengde Medical College between June and October 2007. MATERIALS: Thirty healthy, female, Wistar rats were included in this study. The following compounds were used: leptin; gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) enzyme-linked immunosorbent assay kits. METHODS: Rats were randomly divided into 3 groups at 1, 2, and 4 hours after injection. Each group was subdivided into control and experimental groups (n = 5 animals per group and time point). All rats were subjected to bilateral ovariectomy and, beginning on day 7 after surgery, animals received daily subcutaneous injections of estradiol benzoate (2 μg) for 7 consecutive days. The experimental groups were injected with 5 μL leptin (1 g/L) into the lateral cerebral ventricle, and control groups received an equal volume of physiological saline. MAIN OUTCOME MEASURES: GnRH and LH secretion were examined 1, 2, and 4 hours after injection using GnRH and LH ELISA kits, respectively. RESULTS: In the experimental groups, GnRH secretion significantly increased (P < 0.01), followed by LH secretion (P < 0.01), compared with the control groups. GnRH secretion significantly increased 1 hour after leptin injection (P < 0.01). The LH increase was less pronounced, but still significant (P < 0.01); however, the most prominent LH increase occurred between 1 and 2 hours. Both GnRH and LH secretion reached peak levels at 2 hours after leptin injection. Thereafter, both GnRH and LH secretion decreased, but still maintained very high levels, compared with the control group (P < 0.01). CONCLUSION: Intracerebroventricular leptin injection produced similar effects on GnRH and LH secretion in ovariectomized rats, indicating regulatory effects of leptin on GnRH and LH secretion.

Transplanted iPSC-derived neural stem cells for spinal cord injury

Spinal cord injury(SCI),one of the most devastating central nervous system(CNS)disorders,can lead to severe neurological disabilities,the most severe forms of which include persistent paraplegia or quadriplegia.The efficacy of induced pluripotent stem cell(iPSC)derived neural stem cells(NSC)transplantation on functional recovery following acute spinal cord injury(SCI)was detected.NSC derived from iPSC was characterized by expression of specific markers(SOX2,nestin and PAX6).

Establishment of amyotrophic lateral sclerosis induced pluripotent stem cells and neuronal differentiation

Amyotrophic lateral sclerosis(ALS)is a motor neuron disease that seriously threatens the health of patients.The mechanism is unclear.Most ALS disease models cannot accurately reflect the pathological characteristics of ALS.Induced pluripotent stem cells(iPSC)can best mimic lesions and is used to reveal the mechanism of ALS and develop therapeutic drugs.In the process of iPSC reprogramming,the selection of somatic cells and the optimization of conditions are critical to the progress of iPSC culture.Skin biopsies were used in this study to optimize the isolation and culture method of fibroblasts,and established a optimized somatic cell culture process with high tissue utilization rate,short culture period and high success rate.

Fragmentation of brain apolipoprotein E(ApoE)and its relevance in late onset Alzheimer's disease

Late-onset Alzheimer's disease(LOAD)is the most common cause of dementia in the elderly.Polymorphism in apolipoprotein E(ApoE)gene(ε2,ε3,and ε4)is the greatest LOAD risk factor.The translation products are ApoE2,ApoE3,and ApoE4,respectively.ApoE fragments are present in senile plaques and neurofibillary tangles but their contributions to AD pathogenesis are not clear.