人参总皂甙对大鼠缺血再灌注后神经元凋亡的保护及作用机制的研究

目的探讨人参总皂甙对大鼠缺血再灌注脑组织的保护作用机制。方法利用大鼠大脑中动脉闭塞模型,脑组织切片行Nissel和TUNEL染色,计算调亡的细胞数。结果缺血非治疗组神经细胞数量明显减少,部分神经细胞胞体皱缩,核固缩,具有凋亡细胞的某些光镜特征。治疗组仅见少量神经细胞变性,胞体变形缩小。结论人参总皂甙能明显抑制神经细胞凋亡,从而发挥其神经营养和神经保护作用。

Humanin拮抗Aβ_(31-35)诱导的神经元凋亡

为了研究Humanin(HN)对Aβ31-35诱导的大鼠皮层神经元凋亡的影响,本研究采用原代培养的大鼠皮层神经元,应用流式细胞术、TUNEL法、HO33342染色法检测不同时间(0、8、16h)加入不同浓度的HN对Aβ31-35致神经元凋亡的影响。结果显示:Aβ31-35(25μmol/L)引起培养皮层神经元的凋亡率明显增高,神经元凋亡率由7.43%上升到32.69%;凋亡指数由6.87%上升到28.36%(P<0.05)。与Aβ31-35同时或提前8h给予不同浓度(5,10,20μmol/L)的HN对Aβ31-35(25μmol/L)诱导的神经元凋亡均未产生影响;但20μmol/L的HN提前16h孵育可明显抑制Aβ31-35所致的神经元凋亡,其凋亡率由32.69%下降到20.36%,凋亡指数由28.36%下降到17.57%。本研究结果提示,HN拮抗Aβ31-35致神经元凋亡作用具有剂量和时间依赖性。

Ethanolic extract of propolis induces apoptosis of HL-60 cells in vitro

Objective The aim of the study was to investigate whether ethanolic extract of propolis inhibits the growth and induces apoptosis of HL-60 cel s. Methods HL-60 cel s were treated for 24, 48, 72 h with various concentrations ethanolic extracts of prop-olis （0, 50, 100, and 200 μg/mL）. The proliferation of HL-60 cels was determined using the 3-（4,5-dimeth-ylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay. Subsequently, Hochest 33258 staining and terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） were used to test the apoptosis of HL-60 cel s. We observed the expression levels of Bax and Bcl-2 in HL-60 cel s by immunohistochemistry. Results MTT assay showed that various concentrations of ethanolic extract of propolis had significant inhibitory efect on HL-60 cel proliferation （P〈 0.05）. Typical morphologic changes could be observed by fluorescence microscope and TUNEL. By immunohistochemistry, we found the expression level of Bax was up-regulated, whereas that of Bc1-2 was down-regulated （P 〈 0.05）.Conclusion Ethanolic extract of propolis inhibits leukemia cel proliferation and induces apoptosis in vitro. Its mechanism may be related to the regulation of Bax and Bcl-2 expression and up-regulation of Bcl-2/Bax ratio.

Influence of Valsartan on myocardial apoptosis in spontaneously hypertensive rats

OBJECTIVE: To explore the pathogenic changes of myocardial apoptosis in heart hypertrophy during hypertension and evaluate the anti-apoptosis effect of Valsartan. METHODS: Thirty spontaneously hypertensive rats (SHRs) were divided into two groups: 15 treated with Valsartan (20 mg x kg(-1) x d(-1)) (SHR + Valsartan group), the others with placebo (SHR + placebo group), with 15 normal Wistar rats as control. Systolic blood pressure was measured by the tail-cuff method. The observation period was from 8 to 16 weeks of age. Cardiac apoptosis was evaluated by a Terminal Deoxynucleotidyl Transferase-Mediated dUTP-biotin Nick End Labeling (TUNEL) assay. RESULTS: Mean blood pressure values were 127 +/- 2 mm Hg in controls, 163 +/- 6 mm Hg in the SHR + Valsartan group and 193 +/- 7 mm Hg in the SHR + placebo group at 16 weeks of age, whereas the blood pressure in 8-week-old SHR and Wistar rats were 175 +/- 3 mm Hg and 125 +/- 5 mm Hg, respectively. The ratio of the heart weight over body weight declined in Wistar (3.07 +/- 0.03 mg/g) and SHR + Valsartan groups (3.22 +/- 0.19 mg/g) compared with the SHR + placebo group (4.02 +/- 0.31 mg/g) (P

Relationship between expression of Bax and Bcl-2 proteins and apoptosis in radiation compound wound healing of rats

Objective: To study the relationship between the expression of Bax, Bcl 2 proteins, and apoptosis in radiation compound wound healing of rats. Methods: Apoptosis, Bax and Bcl 2 proteins were estimated by in situ terminal labeling (TUNEL) and immunohistochemical methods. Results: (1) Changes of the apoptosis in wound healing showed three typical characteristics: early occurrence, high frequency and delayed disappearance after radiation to rats when compared with those of simple wound group, which might be an important reason for radiation induced delayed wound healing. (2) The expression of Bax protein increased evidently with the increment of apoptosis and showed a good corresponding relationship with the apoptotic frequency in the process of wound healing. While the expression of Bcl 2 protein decreased obviously as the apoptosis reached a maximum and showed increasing tendency up to normal level when the apoptosis decreased distinctively. Conclusions: Bax and Bcl 2 proteins play an important role in the apoptotic regulation of radiation compound wound healing in rats.

Human neuronal apoptosis secondary to traumatic brain injury and the regulative role of apoptosis-related genes

Objective: To observe human neuronal apoptosis secondary to traumatic brain injury, and to elucidate its regulative mechanism and the change of expression of apoptosis-related genes. Methods: Specimens of brain were collected from cases of traumatic brain injury in humans. The histological and cellular morphology was examined by light and electron microscopy. The extent of DNA injury to cortical neurons was detected by using TUNEL. By in situ hybridisation and immunohistochemistry the mRNA changes and protein expression of Bcl-2, Bax, p53, and caspase 3 p20 subunit were observed. Results: Apoptotic neurons appeared following traumatic brain injury, peaked at 24 hours and lasted for 7 days. In normal brain tissue activated caspase 3 was rare, but a short time after trauma it became activated. The activity peaked at 20-28 hours and remained higher than normal for 5-7 days. There was no expression of Bcl-2 mRNA and Bcl-2 protein in normal brain tissue but 8 hours after injury their expression became evident and then increased, peaked at 2-3 days and remained higher than normal for 5-7 days. The primary expression of Bax-mRNA and Bax protein was high in normal brain tissue. At 20-28 hours they increased and remained high for 2-3 days; on the 7th days they returned to a normal level. In normal brain tissue, p53mRNA and P53 were minimally expressed. Increased expression was detected at the 8th hour, and decreased at 20-28 hours but still remained higher than normal on the 5th day. Conclusions: Following traumatic injury to the human brain, apoptotic neurons appear around the focus of trauma. The mRNA and protein expression of Bcl-2, Bax and p53 and the activity of caspase 3 enzyme are increased.

Effects of penehyclidine hydrochloride on apoptosis of lung tissues in rats with traumatic acute lung injury

Objective： To investigate the effects ofpenehyclidine hydrochloride on apoptosis of lung tissue cells and its mechanism in acute lung injury following blunt chest trauma in rats. Methods： Sprague Dawley （SD） rats （n=54） weighing （250-25） g were divided equally and randomly into three groups： normal control group （C group, n= 18）, trauma model group （T group, n= 18） and penehyclidine hydrochloride treatment group （P group, n=18）. Each group was further divided into three subgroups according to the time points of 3, 12 and 24 hours after experiment （at each time point, n=6 for each subgroup）. Rats of P group were intraperitoneally injected with penehyclidine hydrochloride for 2 mg/kg immediately after blunt chest trauma and rats in its 24 hours subgroup were once again injected with penehyclidine hy- drochloride in the same dose 12 hours after injury. Lung tissue samples were collected at every time point and cell apoptosis in lung tissues were measured by TUNEL. Apoptotic index （AI） was calculated, expressions of bax and bcl-2 were detected by immunohistochemical staining of SABC, and lung tissue sections were taken for light and electron microscopic observation. Results： As compared with C group, at every time point, AI and expressions ofbax and bcl-2 in T group were higher （P〈0.05）, and the ratio of bcl-2/bax markedly decreased （P〈0.05）, especially in the 24 hours subgroup. The ratio in T group （0.468±0.007） was lower than that in C group （1.382±0.058, t=12.5, P〈0.01）. Lung tissue injuries were significant under a light microscope, and the number of apoptotic cells increased obviously under a transmission electron microscope. As compared with T group at the same phase, AI and expression of bax decreased in P group （P〈0.05 and P〈0.01）, while the expression of bcl-2 increased significantly （P〈0.01）, and the ratio of bcl-2/bax markedly increased （P〈0.05）, especially in the 24 hours subgroup. The ratio in P group （1.012-0.070） was much higher than that in T group （0.468±0.007, t=-8.3, P〈0.01）. The injury of lung tissues was relieved, and apoptosis of cells decreased obviously under a transmission electron microscopic observation. Conclusions： Apoptosis and expressions ofbax and bcl-2 in lung tissues might be involved in the pathogenesis of lung injury induced by blunt chest trauma. Penehyclidine hydrochloride can alleviate lung injuries by inhibiting apoptosis of lung tissue cells, during which effects ofpenehyclidine hydrochloride on regulating expressions ofbax and bcl-2 may play an important role.