Therapeutic potential of Naja naja atra venom in a rat model of diabetic nephropathy / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study the protective effects of naja naja atra venom (NNAV) in a rat model of diabetic nephropathy (DN).</p><p><b>METHODS</b>The rat diabetes model was induced by intraperitoneal injection of streptozotocin (STZ). Thirty-two model rats were randomly divided into one DN group (n=8) and three treatment groups (n=8 each) that received NNAV at doses of 30, 90, or 270 μg/(kg·day) via oral gavage, another eight rats as normal controls. After 12 weeks, all rats were sacrificed and the changes in serum and urine biological index levels were determined by colorimetric assay. Microalbumin (mALB), N-acetyl-β- glucosaminidase (NAG) and cystatin C (CysC) concentrations were measured by ELISA. Renal tissues were sliced for pathological and immunohistochemical observations.</p><p><b>RESULTS</b>Comparied with the DN group, serum glucose was decreased by 31.04%, total cholesterol 21.96%, triglyceride 23.78%, serum creatinine 19.83%, blood urea nitrogen 31.28%, urinary protein excretion 45.42%, mALB 10.42%, NAG 20.65%, CysC 19.57%, whereas albumin increased by 5.55%, high-density lipoprotein-cholesterol 59.09%, creatinine clearance 19.05% in the treatment group by NNAV administration at dose of 90 μg/(kg·day). NNAV also reduced the levels of malondialdehyde in serum (22.56%) and kidney tissue (9.79%), and increased superoxide dismutase concentration in serum (15%) and decreased it in renal tissue (8.85%). In addition, under light microscopy kidney structure was improved and glomerular hypertrophy decreased by 8.29%. As shown by immunohistochemistry, NNAV inhibited transforming growth factor-β1 by 6.70% and nuclear actor-κB by 5.15%.</p><p><b>CONCLUSION</b>NNAV improves biological indexes in DN, and it may exert renoprotective effects in rats with STZ-induced diabetes.</p>

Ursolic acid induces human hepatoma cell line SMMC-7721 apoptosis via p53-dependent pathway / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Ursolic acid (UA) is a ubiquitous molecule in the plant kingdom with specific anticancer effects that have been shown in vitro and in vivo. Although UA can inhibit the proliferation of liver cancer cells and induce apoptosis of many types of tumor cells, the molecular mechanism of its anti-hepatoma activity is still not well defined. The objective of this study was to investigate the inhibitory effect and mechanisms of UA on the human hepatoma cell line SMMC-7721.</p><p><b>METHODS</b>After treatment with UA, the growth inhibition of SMMC-7721 cells was assessed by MTT assay. Cells were also evaluated by flow cytometric analysis, Wright-Giemasa staining, Hoechst 33258 staining and transmission electron microscope after they were induced by UA. DNA microarray technology was used to investigate the gene expression pattern of SMMC-7721 cells exposed to UA 40 micromol/L. The molecular mechanism of cells death was analyzed by real-time RT-PCR and Western blotting.</p><p><b>RESULTS</b>The proliferation of SMMC-7721 cells was significantly inhibited in a dose- and time-dependent manner after UA treatment. UA induced cell cycle arrest and apoptosis. The DNA microarray analysis indicated that 64 genes were found to be markedly up- or down-expressed, including GDF15, SOD2, ATF3, and fos. The result of Western blotting showed the apoptotic proteins p53 and Bax were up-regulated while the anti-apoptotic protein Bcl-2 was down-regulated. Real-time RT-PCR confirmed UA could up-regulate the mRNA expressions of GDF15, SOD2, ATF3 and down-regulate the mRAN expression of fos. Meanwhile these effects were partly blocked by pretreatment with the p53 inhibitor Pft-alpha.</p><p><b>CONCLUSION</b>Activation of the p53 pathway is involved in UA inhibition of SMMC-7721 human hepatocellular carcinoma cell growth and induction of apoptosis.</p>

Advances in research of ketamine addiction mechanism / 法医学杂志

Ketamine is a phencyclidine derivative acting primarily as a noncompetitive antagonist of N-methyl-D-aspartate (NMDA) excitatory glutamate receptors. As a common intravenous anaesthetic in clinic, it is also increasingly abused because of its hallucination and addiction effects. Based on the pharmacological and toxicologic characteristics of ketamine and the acknowledged addiction mechanism of other abused drugs, this article reviews the possible addiction mechanism of the ketamine in the aspects of its enhanced effects and reward systems, the anatomic structures, the related receptors and the individual differences.

Ultrastructural analysis of glioma stem cells-progenitors / 中华肿瘤杂志

<p><b>OBJECTIVE</b>It is well known that glioma stem cells-progenitors (GSCP) proliferate indefinitely and hardly differentiate in vitro, however, the reasons remain unknown. The aim of this study was to explore the ultrastructural basis of GSCP.</p><p><b>METHODS</b>GSCP, kept by our laboratory, were collected, embedded, and cut into ultrathin sections and observed under the transmission electron microscope.</p><p><b>RESULTS</b>A single GSCP usually had relatively well developed mitochondria, Golgi apparatuses, ribosomes, and undeveloped rough endoplasmic reticulum, but seldom lysosomes and no typical autophagosomes were found, and the nuclear-cytoplasmic ratio was high. The nuclei frequently contained huge amounts of euchromatin and a small quantity of heterochromatin, and in most nuclei there were only one nucleolus, however, two or more nucleoli were also common. Typical apoptotic cells could hardly be found in tumor-spheres, and between neighboring cells in tumor-spheres there were incompletely developed desmosomes or intermediate junction.</p><p><b>CONCLUSION</b>The ultrastructural features of glioma stem cells-progenitors showed that BTSCP were very primitive and the lack of autophagy and the underdevelopment of some other cellular organelles are probably the reasons for the differential inhibition of GSCPs.</p>

Mechanisms of lysosomal proteases participating in cerebral ischemia-induced neuronal death / 神经科学通报·英文版

There are three different types of cell death, including apoptosis (Type I), autophagic cell death (Type II), and necrosis (Type III). Ischemic neuronal death influences stroke development and progression. Lysosomes are important organelles having an acidic milieu to maintain cellular metabolism by degrading unneeded extra- and intracellular substances. Lysosomal enzymes, including cathepsins and some lipid hydrolases, when secreted following rupture of the lysosomal membrane, can be very harmful to their environment, which results in pathological destruction of cellular structures. Since lysosomes contain catalytic enzymes for degrading proteins, carbohydrates and lipids, it seems natural that they should participate in cellular death and dismantling. In this review, we discuss the recent developments in ischemic neuronal death, and present the possible molecular mechanisms that the lysosomal enzymes participate in the three different types of cell death in ischemic brain damage. Moreover, the research related to the selective cathepsin inhibitors may provide a novel therapeutic target for treating stroke and promoting recovery.

The roles of the proteasome pathway in signal transduction and neurodegenerative diseases / 神经科学通报·英文版

There are two degradation systems in mammalian cells, autophagy/lysosomal pathway and ubiquitin-proteasome pathway. Proteasome is consist of multiple protein subunits and plays important roles in degradation of short-lived cellular proteins. Recent studies reveal that proteasomal degradation system is also involved in signal transduction and regulation of various cellular functions. Dysfunction or dysregulation of proteasomal function may thus be an important pathogenic mechanism in certain neurological disorders. This paper reviews the biological functions of proteasome in signal transduction and its potential roles in neurodegenerative diseases.

Expression of cathepsin-B and -D in rat's brain after traumatic brain injury / 法医学杂志

OBJECTIVE@#To study the expression of cathepsin-B and -D in different time point after traumatic brain injury.@*METHODS@#Traumatic brain injury (TBI) model was established on rats, cathepsin-B and cathepsin-D immunofluorescence staining and confocal microscope analysis were performed. Positive cells were counted by confocal microscope and image analysis techniques were used to determine the morphological changes in each group.@*RESULTS@#Immunofluorescence staining results showed that cathepsin-B was activated 1 hour after TBI while cathepsin-D was not activated until 12hour after TBI. Both of them got to their peak during 4 to 8days, and kept a high level of activating 32days after TBI. Cathepsin-B and -D positive cells did not merge with caspase-3 positive cells until 6 h after TBI.@*CONCLUSION@#Cathepsin-B and -D could be the diagnostic markers of TBI and can estimating time course of lateral TBI. They blocked caspase-3 activation at the beginning period after TBI and started to promote cell death with caspase-3 6 h after TBI.

A short-chain alpha-neurotoxin from Naja naja atra produces potent cholinergic-dependent analgesia / 神经科学通报·英文版

Objective To investigate the analgesia induced by cobrotoxin (CT) from venom of Naja naja atra, and the effects of atropine and naloxone on the antinociceptive activity of CT in rodent pain models. Methods CT was administered intraperitoneally (33.3, 50, 75 mu g/kg), intra-cerebral venticularly (2.4 mu g/kg) or microinjected into periaqueductal gray (PAG, 1.2 mu g/kg). The antinoCiceptive action was tested using the hot-plate test and the acetic acid writhing test in mice and rats. The involvement of cholinergic system and the opioid system in CT-induced analgesia was examined by pretreatment of animals with atropine (0.5 mg/kg, im or 10 mg/kg, ip) or naloxone (3 mg/kg, ip). The effect of CT on motor activity was tested using the Animex test. Results CT (33.3, 50 and 75 mu g/kg, ip) exhibited a dosedependent analgesic action in mice as determined with hot-plate test and acetic acid writhing test. In the mouse acetic acid writhing test, the intra-cerebral ventricle administration of CT 2.4 mu g/kg (1/23th of a systemic dose) produced marked analgesic effects. Microinjection of CT 1.2 mu g/kg (1/46th of systemic dose) into the PAG also elicited a robust analgesic action in the hot-plate test in rats. Atropine at 0.5 mg/kg (im) or naloxone at 3 mg/kg (ip) failed to block the analgesic effects of CT, but atropine at 10 mg/kg (ip) did antagonize the analgesia mediated by CT in the mouse acetic acid writhing test. At the highest effective dose of antinociception (75 mu g/kg), CT did not change the spontaneous mobility of mice. Conclusion These results suggest that CT from Naja naja atra venom has analgesic effects. Central nervous system may be involved in CT's analgesic effects and the PAG may be the primary central site where CT exerts its effects. The central cholinergic system but not opioid system appears to be involved in the antinociceptive action of CT.

Mitochondrial dysfunction and Huntington disease / 神经科学通报·英文版

Huntington disease (HD) is a chronic autosomal-dominant neurodegenerative disease. The gene coding Huntingtin has been identified, but the pathogenic mechanisms of the disease are still not fully understood. This paper reviews the involvement of mitochondrial dysfunction in pathogenesis of HD.

Analgesic effects of receptin, a chemically modified cobratoxin from Thailand cobra venom / 神经科学通报·英文版

Objective To investigate the analgesia induced by receptin (REC), a chemically modified cobratoxin (CTX, a long-chain postsynaptic alpha -neurotoxin from Thailand cobra venom), and the effects of atropine and naloxone on antinociceptive activity of REC in rodent pain models. Methods REC was administered intraperitoneally (5 mg/kg, 7.07 mg/kg, or 10 mg/kg, i.p.) or intra-cerebral venticularly (62.5 mu g/kg, i.c.v.). The antinociceptive action was determined using the hot-plate test, the acetic acid writhing test and tail flick assay in mice and rats. The involvement of cholinergic and the opioid peptidergic systems in REC-induced analgesia were examined by pretreatment of animals with atropine (Atr; 0.5 mg/kg, i.m. or 10 mg/kg, i.p.) or naloxone (Nal; 3 mg/kg, i.p.). The effect of REC on motor activity was tested using the Animex test in mice. Results REC (5 mg/kg, 7.07 mg/kg or 10 mg/kg, i.p.) exhibited a dose-dependent analgesic action in mice as determined with hot-plate test and acetic acid writhing test. The significant analgesia of REC was seen 2 h to 3 h after its administration. In the rat-tail flick assay, the administration of REC at 62.5 mu g/kg (1/160 of systemic dose; i.c.v.) produced marked analgesic effects. Atropine at 0.5 mg/kg (i.m.), 10 mg/kg (i.p.) or naloxone at 3 mg/kg (i.p.) failed to block the analgesic effects of REC. REC at the highest effective dose of 10 mg/kg did not change the spontaneous mobility of mice. Conclusion These results demonstrate that REC has analgesic effect. This activity appears to be mediated through the peripheral nervous system though central nervous system may contribute to REC' s analgesic effects. The central cholinergic system and opioid peptidergic system appear not to be involved in the antinociceptive action of REC.

Regulatory genes controlling neural stem cells differentiation into neurons / 神经科学通报·英文版

The recent progress in neural stem cells (NSCs) research has shed lights on possibility of repair and restoration of neuronal function in neurodegenerative diseases using stem cells. Induction of stem cells differentiate into mature neurons is critical to achieve the clinical applications of NSCs. At present, molecular mechanisms modulating NSC differentiation are not fully understood. Differentiation of stem cells into neuronal and glial cells involves an array of changes in expression of transcription factors. Transcription factors then trigger the expression of a variety of central nervous system (CNS) genes that lead NSCs to differentiate towards different cell types. In this paper, we summarized the recent findings on the gene regulation of NSCs differentiation into neuronal cells.

Inflammatory mechanism in ischemic neuronal injury / 神经科学通报·英文版

Inflammation has been implicated as a secondary mechanism underlying neuronal injury induced by ischemia. A variety of experimental models, including thromboembolic stroke, focal and global ischemia, have been used to evaluate contributions of inflammation to neuronal damage. The vasculature endothelium promotes inflammation through upregulation of adhesion molecules such as intercellular adhesion molecule (ICAM), E-selectin, and P-selectin that bind to circulating leukocytes and facilitate migration of leukocytes into the central nervous system (CNS). Once being in the CNS, leukocytes produce cytotoxic molecules that promote cell death. The response of macrophages and microglia to injury may either be beneficial by scavenging necrotic debris or be detrimental by facilitating cell death of neurons that would otherwise recover. While many studies have tested these hypotheses, the significance of inflammation in stroke models is inconclusive. This review summarizes data regarding roles of cell adhesion molecules, astrocytes, microglia and leukocytes in stroke.