Effect of ACTH on pain behavior and the level of brain-derived neurotrophic factor and corticotropin-releasing hormone in the hippocampus of rats with chronic pain

AIM: To observe the effect of adrenocorticotropic hormone(ACTH) on the levels of brain-derived neurotrophic factor(BDNF), trkB and corticotropin-releasing hormone(CRH) in the hippocampus of arthritic rats.METHODS: The BDNF immunoreactivity(IR) and CRH-positive neurons were stained with immunohistochemistry and in situ hybridization methods, respectively.RESULTS: The BDNF-IR, CRH mRNA-positive neurons in the contralateral hippocampus of the arthritic rats were increased significantly, which was decreased markedly by intraperitoneal injection of ACTH. However, the effect of ACTH was attenuated after adrenalectomy(ADX).CONCLUSION: These results suggest that BDNF and CRH in the hippocampus of arthritic rats were involved in the modulation of chronic pain, ACTH produced its analgesic effect by inhibiting the increase in BDNF and CRF level. Adrenal is critical to the analgesic action of ACTH.     

The central role of corticotropin-releasing hormone in stress-induced hyperthermia and LPS-induced fever in rats

AIM:To further investigate the role of central corticotropin-releasing hormone in stress-induced hyperthermia and lipopolysaccharide (LPS)-induced fever in the rat.METHODS:Test substances were administered intracerebroventricularly (icv) via a third ventricle cannula. Body temperature responses were monitored at 30 min intervals using colonic thermistor probes. Arginine vasopressin (AVP) level in the ventral septal area (VSA) determined by radioimmunoassay. RESULTS:In normal saline controls,rats were handled to take the colonic temperature,their body temperature significantly increased with a peak of(0.88±0.31)℃.The injection(icv)of α-helical CRH(9-41),a CRH-41 receptor antagonists,markedly attenuated the stress-induced hyperthermia within 90 min after injection of normal saline.LPS(300 ng,icv)stimulated a biphasic rise in the colonic temperature,the 3.5 h thermal response index(TRI_3.5)and AVP levels in the VSA of LPS-treated rats were higher than those of control rats.The AVP responses to LPS were inhibited significantly by blockade of central CRH actions using α-helical CRH(9-41)(5μg,icv)administered 10 min prior to LPS,whileα-helical CRH(9-41)(5μg,icv)resulted in exacerbated febrile responses to LPS(300 ng,icv). CONCLUSION:Central CRH plays an important role in stress-induced hyperthermia. The injection (icv) of α-helical CRH(9-41) enhances markedly LPS-induced fever in rats. CRH is a dual action molecule in LPS-induced fever, which itself mediates LPS-induced fever, at the same time, and limits the rise in body temperature during fever through actions of AVP in the VSA and glucocoticoids.     

Activation of corticotrophin releasing hormone-containing neurons in hypothalamic paraventricular nucleus contributes to sympathoexcitation in rats with congestive heart failure

AIM:To observe the expression of corticotropin releasing hormone (CRH) within the paraventricular nucleus of hypothalamus (PVN) and to explore the relationship between the activated CRH-containing neurons and sympathetic activity in rats with heart failure (HF).METHODS:Healthy male Sprague-Dawley (SD) rats were subjected to coronary artery ligation to induce HF,and chronic intracerebroventricular (ICV) infusion was performed by osmotic pump for 4 weeks.The rats in sham group and HF group were given vehicle (VEH;artificial cerebrospinal fluid 0.25 μL/h).The rats in HF plus treatment group were treated with CRH competitive inhibitor αh-CRH (15 mg/h).Meanwhile,the Lewis rats and Fischer 344 rats for control study also underwent coronary ligation to induce HF or sham surgery.After 4 weeks,left ventricular end-diastolic pressure (LVEDP) and maximum positive/negative change in pressure over time (±dp/dt_max) were determined.The right ventricular-to-body weight (RV/BW) and lung-to-body weight (lung/BW) ratios were calculated.The renal sympathetic nerve activity (RSNA) was recorded and the plasma norepinephrine (NE) level was measured.The expression of CRH in the PVN combined with the plasma adrenocorticotrophic hormone (ACTH) levels were measured.RESULTS:Compared with the sham-SD rats,the HF-SD rats had a greater number of CRH positive neurons in the PVN (accordingly the plasma ACTH levels were increased),accompanied by decreased±dp/dt_max and increased RSNA,plasma NE,LVEDP,lung/BW and RV/BW.However,ICV treatment with αh-CRH attenuated these changes in the HF-SD rats (P<0.05).Compared with the sham-Fisher 344 rats,the HF-Fisher 344 rats also had a greater number of CRH positive neurons in the PVN (accordingly the plasma ACTH levels were increased).In addition,they had significantly increased RSNA and plasma NE level,higher LVEDP,RV/BW and lung/BW,and lower±dp/dt_max(P<0.05).Compared with the SHAM-Lewis rats,the HF-Lewis rats had not significantly changed in the above parameters.CONCLUSION:In CHF,the CRH-containing neurons in PVN are activated,thus aggravating cardiac function by increasing sympathoexcitation.     

Effects of exogenous ADM on HPA axis in early stage of acute mechanical renal trauma

AIM: To explore the effects of exogenous adrenomedullin(ADM) on hypothalamus-pituitary-adrenal cortex (HPA)axis in the early stage of acute mechanical renal trauma.METHODS: Healthy adult Wistar rats were randomly divided into 4 groups: 8 in control group, 32 in trauma group, 32 in the group injected with ADM before trauma and 32 in the group injected with ADM after trauma. To induce renal trauma, the rats in the latter 3 groups were subjected to mechanical impact directly on the skin of renal region by a free-fall iron hammer. The rats in 2 treatment groups were injected with ADM (0.1 nmol/kg) intraperitoneally 10 min just before and after trauma,respectively. The rats in the 3 groups with kidney injury were executed in batches by drawing all the blood quickly in the hearts at the time points of 1 h, 6 h, 12 h and 24 h after trauma. The hypothalamus tissues were also collected. The expression of corticotropin-releasing hormone(CRH) in hypothalamus and the concentrations of adrenocorticotropic hormone(ACTH) and cortisol(CORT) in plasma were detected by immunohistochemical method and radioimmunoassay. RESULTS: The expression of CRH in hypothalamus and the concentrations of ACTH and CORT in plasma in trauma group,but were slightly higher than those in control group,but without statistical significance. The expression of CRH in hypothalamus at 1 h and 24 h, the concentration of ACTH in plasma at 12 h and CORT at 6 h,12 h and 24 h in the group injected with ADM before trauma significantly higher than those in trauma group and control group (P<0.05). The expression of CRH in hypothalamus at 1 h, 6 h and 12 h and the concentration of CORT in plasma at 12 h and 24 h in the group injected with ADM after trauma were obviously higher than those in trauma group and control group (P<0.05). CONCLUSION: Exogenous ADM stimulates HPA axis and activates the function of HPA axis markedly. However, the different layers of HPA axis have different responses to exogenous ADM. Injection of ADM before or after trauma has different effects on HPA axis.     

Role of endogenous arginine vasopressin in soman-induced hypothermia in rats

AIM: This study was designed to examine whether endogenous arginine vasopressin (AVP) is involved in soman-induced hypothermic process. METHODS: Core temperature was measured at 60 min intervals with digital thermometer. Effect of AVP V₁ receptor antagonist (30 μg/kg, ip) on soman-induced hypothermia was observed in rats, and plasma AVP concentration was measured at 2 h after administration of soman(60 μg/kg, sc). RESULTS: Administration of soman led to a marked hypothermia. Core temperature recovered to basal levels at 7 h after soman treatment. Plasma AVP concentration increased markedly at 2 h after soman treatment, and administration of AVP V₁ receptor antagonist markedly blocked the hypothermic effect of soman. CONCLUSION: The data indicate that AVP is involved in soman-induced hypothermia in the rat.     

Effect of hyperbaric oxygen on periodontitis with psychological stress in rats

AIM: To investigate the role of chronic psychological stress on periodontitis and the effects of hyperbaric oxygen (HBO) on periodontitis with psychological stress in rats. METHODS: Male special pathogen-free Wistar rats (n=80) were randomly divided into 4 groups: (1)normal control group; (2)experimental periodontitis group: the periodontitis model was induced by wrapping 3/0 silk ligature inoculated with Porphyromonas gingivalis around the left maxillary second molar of the rats; (3)psychological stress stimulation group; (4)periodontitis model with stress stimulation group. Psychological stress was removed at the 9th week after ligature, and 4 rats from each experimental group were randomly chosen for HBO treatment. The rats were sacrificed at the 2nd, 4th, 8th and 10th weeks after ligature. The levels of blood glucose, adrenocorticotropic hormone (ACTH), corticosterone and adrenaline were measured as the stress markers. The histological changes of periodontal tissues were observed under microscope with HE staining. RESULTS: The levels of blood glucose, ACTH, corticosterone and adrenaline in psychological stress stimulation group and periodontitis with stress group were significantly higher than those in control group and experimental periodontitis group at the 2nd and 4th weeks after ligature (P<0.05). The levels of the stress markers were significantly lower than those in untreated groups in the 10th week after HBO (P<0.01). The sites of gingival attachment were normal in control group and psychological stress stimulation group. Periodontal pocket, and periodontal attachment loss (AL) were observed in experimental periodontitis group. The tissue damage was much heavier in periodontitis model with stress stimulation group as the furcation of tooth was exposed and the tissue damage was observed on both sides of the adjacent teeth. No significant difference of AL between psychological stress stimulation group and normal control group during the experiment was observed. The AL in periodontal model with stress stimulating group was significantly higher than that in experimental periodontitis group at the 2nd, 4th and 8th weeks (P<0.01). The level of AL was attenuated at the 10th week after HBO (P<0.01). No difference of histological change in periodontal tissues was observed between control group and psychological stress stimulation group. Severer inflammatory changes and alveolar bone destruction were observed in periodontitis with stress group than those in experimental periodontitis group. The levels of inflammation reduced at the 10th week after HBO. CONCLUSION: Stress stimulation is one of the inducing factors of periodontitis in rats, which aggravates periodontitis. HBO may represent a useful way in treating psychological stress periodontitis.     

Effects of sport fatigue and poverty of movement on neuroendocrine system in Wistar rats

AIM: To observe the different changes of neuroendocrine systems between the state of sport fatigue and poverty of movement. METHODS: 60 male Wistar rats were randomly divided into three groups: normal control group, sport fatigue model group and poverty of movement model group (20 rats in each group). The sport fatigue model was established by the method of combining basal diet and loaded swimming during 2 weeks, whereas the method of restricted activities was used to establish the poverty of movement model with total experimental time of 10 weeks. By the end of experiment, the climbing pole time was determined. The contents of hypothalamus thyrotropin releasing hormone (TRH), and serum norepinephrine (NE) and epinephrine (E) in rats with different treatments were determined by ELISA. In addition, the changes of hypothalamus corticotropin release hormone (CRH), pituitary adrenocorticotropic hormone (ACTH) and thyroid stimulating hormone (TSH), and serum corticosterone (CORT), triiodothyronine (T3), tetraiodothyronine (T4) were determined by radioimmunoassay to evaluate the functions of adrenergic nerve-adrenomedullin system, hypothalamo-pituitary-adrenal (HPA) axis and hypothalamo-pituitary-thyroid (HPT) axis. RESULTS: Compared to control group, the climbing pole time of the animals was obviously decreased in two model group. The adrenergic nerve-adrenomedullin system and HPA axis were inhibited in sport fatigue model rats, but HPT axis was unchanged. Interestingly, the HPA axis was hyperfunctional and HPT axis was inhibited in poverty of movement model rats. However, no change in the adrenergic nerve-adrenomedullin system was observed. CONCLUSION: Sport fatigue and poverty of movement all affect neuroendocrine system and lead to the adjustment mechanism imbalance, but the target and tendency are different.     

Immunohistochemical study on ACTH cells and TSH cells of pituitary pars distails of morphine dependent male rats and its restoration after withdrawal

AIM: To investigate the change of adrenocorticotropic hormone (ACTH) cells and thyroid- stimulating hormone(wn) cells of pars distalls of pituitary gland of morphine dependent dependent rats and its restoration after withdrawal. METHODS: Morphine dependent model of male rats was made by subcutaneous injection of mor- phine and the adstinent model was made after withdrawal. Changes of ACTH cells and TSH cells of pars distails of pituitary gland were detected by immunohistochemistoy survey and image analysis. RESULTS: The intensity of positive staining and the numerical density of ACTH and TSH immunoreactive cells were weakened (P＜ 0.01), after withdrawal from morphine for a short time the changes would exist continuously. CONCLUSION: Morphine may give rise to disorder of endocrine of pituitary gland of male rats, which may incompletely restore after withdrawal for a short time.     

Effects of voluntary wheel running exercise on depressive-like behavior and circadian rhythmic alterations of neuroendocrine induced by chronic unpredictable mild stress in rats

AIM: To investigate the effect of 8-week middle intensity voluntary wheeling exercise on the depressive-like behavior and the circadian rhythmic alterations of plasma hormone and peptide induced by chronic unpredictable mild stress (CUMS) in rats. METHODS: Male Sprague-Dawley rats (n=90) were randomly divided into model group, model+exercise group and control group. Rats in model+exercise group received 8-week voluntary wheel running exercise plus CUMS procedure during the last 3 weeks at the same time. Exploratory locomotor activity was assessed by open field test, the anxiety-like behavior was measured by elevated plus-maze test, and lack of pleasure was detected by sucrose preference test. Blood samples were collected at each of 6 time points (ZT1, 5, 9, 13, 17 and 21 on the 2nd day after behavior testing). Plasma concentrations of corticosterone (CORT), melatonin (MT) and vasoactive intestinal peptide (VIP) were detected by ELISA. The plasma concentration of adrenocorticotropic hormone (ACTH) was measured by radioimmunoassay. The circadian rhythm changes of serum CORT, MT, VIP and ACTH concentrations in each group were compared by cosinor analysis. RESULTS: Compared with control group, locomotor activity, weight gain and sucrose consumption in model group were significantly reduced (P<0.01). The values of the percentage of open-arm time (OT%) and open arm entries (OE%) were obviously lower in model group than those in control group (P<0.01). Eight-week voluntary wheel running exercise may improve the above depression behavior caused by CUMS. The rats in model group showed an obvious disorder in circadian rhythm of plasma ACTH and CORT, including phase advance and decrease in amplitude. There also showed a markedly blunted circadian rhythm and decreased level of plasma MT in model rats compared to control rats. VIP expression was significantly higher than that in control group with 24 h rhythm, but the amplitude was significantly lower than that in control group, peak phase also delayed for 6 h. Eight-week exercise significantly ameliorated the abnormal expression and the disturbance secretion rhythm of ACTH, CORT, MT and VIP in plasma. CONCLUSION: Eight-week voluntary wheeling exercise ameliorates CUMS-induced depressive-like behaviors probably by rescuing the disturbed circadian rhythms and abnormal secretion of these neuroendocrine factors.     

Role of endogenous arginine vasopressin in tonic thermoregulatory processes in rats during the light phase

AIM: To determine the role of endogenous arginine vasopressin (AVP) in tonic thermoregulatory processes in rats during the light phase. METHODS: The core temperature (Tc) and temperature in brown adipose tissue (BAT) were simultaneously measured by telemetry in adult male Sprague-Dawley rats at an ambient temperature of 22 °C during a 12-h light/12-h dark photoperiod. At 10:00,the rats were intraperitoneally injected with V_1a vasopressin receptor antagonist (30 μg/kg) or AVP (10 μg/kg). Plasma AVP concentration was measured by an enzyme-linked immunosorbant assay during the light phase and dark phase. Serum triglyceride, free fatty acid and glycerol were measured 60 min after AVP treatment. Grooming activities were also observed at 10-min intervals after AVP treatment. RESULTS: V_1a vasopressin receptor antagonist elevated the Tc and BAT temperature during the light period. The plasma AVP level was significantly elevated when Tc and BAT temperature decreased during the light phase. Intraperitoneal injection of AVP elicited rapid drop in Tc concomitant with a marked decrease in BAT temperature, and also increased grooming behavior in the rats. Intraperitoneal injection of AVP produced a decrease in serum free fatty acid and glycerol, and an increase in serum triglyceride. CONCLUSION: Endogenous AVP, acting through V_1a vasopressin receptor, is involved in tonic thermoregulatory processes in male rats during the light phase because plasma AVP concentration is higher during light period than that during dark period, and V_1a vasopressin receptor antagonist elevates the Tc and BAT temperature. AVP decreases BAT temperature, serum free fatty acid and glycerol, and increases grooming behavior, suggesting that the mechanism of AVP-induced hypothermia is involved in suppression of lipolysis, decrease in BAT thermogenesis and increase in heat loss.     

Influence of chronic psychological stress on periodontitis and serum isoenzyme LDH1 in rats

AIM: To investigate the role of chronic psychological stress on periodontitis and serum level of isoenzyme LDH1 in rats. METHODS: Eighty female special pathogen-free Wistar rats were randomly divided into 4 groups:(1) normal control group; (2) experimental periodontitis group: the periodontitis model was induced by wrapping 3/0 silk ligature inoculated with putative periodontopathic bacteria around the left maxillary second molar of the rats; (3) psychological stress stimulation group: the rats were treated with stress stimulation alone; (4) periodontitis model with stress stimulation group: the periodontitis models were induced by wrapping 3/0 silk ligature inoculated with putative periodontopathic bacteria around the left maxillary second molar of the rats, and then treated with stress stimulation. The rats were sacrificed at 2nd, 4th, 6th and 8th weeks after ligature. The levels of blood glucose and adrenocorticotropic hormone (ACTH) were measured as the stress markers, and the serum isoenzyme lactate dehydrogenase 1(LDH1) was used to evaluate the severity of hypoxia. The histological changes of periodontal tissues were observed under microscope with HE staining. RESULTS: The levels of blood glucose and ACTH in stress group and periodontitis with stress group were significantly higher than those in control group and experimental periodontitis group at the 2nd and 4th weeks after ligature (P<0.01). The level of serum LDH in periodontitis with stress group was significantly higher than that in control group. The level of serum LDH1 in periodontitis with stress group was significantly lower than that in control group (P<0.01). No difference of histological change in periodontal tissues was observed in control group and stress group. Severer inflammatory changes and alveolar bone destruction were observed in periodontitis with stress group than those in experimental periodontitis group. CONCLUSION: Stress stimulation is one of the inducing factors of periodontitis in rats that aggravates periodontitis by decreasing the tissue oxygenation.     

Nucleus tractus solitarius participates in regulation of paraventricular nucleus vasopressinergic neurons on gastric ischemia-reperfusion injury in rats

AIM: To investigate the role of the nucleus tractus solitarius (NTS) in the regulation of paraventricular nucleus (PVN) AVP-ergic neurons on gastric ischemia- reperfusion injury (GI-RI). METHODS: Male SD rats were used in experiments. The celiac artery were clamped for 30 min and reperfused 1 h by removal of the clamp to obtain the ischemia-reperfusion state. The mechanism was analysed with nucleus electrical stimulation, electrolytic lesion and nucleus microinjection technique. RESULTS: Microinjection of arginine-vasopressin (AVP) into PVN obviously attenuated the GI-RI and dose-dependent effects were observed (r=-0.477, P<0.05) ; NTS lesion or microinjection of AVP antagonist into NTS both eliminated the attenuate effect of electrical stimulation of PVN on GI-RI. The effect of microinjection of AVP into NTS was similar to microinjection of AVP into PVN. CONCLUSION: The NTS participates in regulation of PVN AVP-ergic on GI-RI, which is mediated by the AVP receptor in the NTS.     

Urocortin,a novel peptide of the corticotropin releasing hormone family

Urocortin, a novel peptide of the cortiotropin releasiong hormone (CRH) family, was discovered in 1995 in the rat brain and subsequently cloned and localized to human chromosome 2. It can bind to both CRH type 1 receptor and CRH type 2 receptor, as well as CRH binding protein. Especially to CRH type 2 receptor, urocortin binds to it with 40 times more potency than CRH does. Therefore, urocortin is thought to be an en dogenous ligand for CRH type 2 receptor. Immunoreactive urocortin and urocortin mRNA were localized in many areas such as mammalian brain, cardiovascular system, placenta. It is believed that urocortinmay play important physiological roles as a neuropeptide not only in the central nervous system but also in peripheral tissues.     

Effect of different ambient temperatures on arginine vasopressin-induced hypothermia in rats and its relationship with heat loss from the tail

AIM：To determine the effect of different ambient temperatures on arginine vasopressin (AVP)-induced hypothermia in rats and its relationship with the change of heat loss from the tail, and to assess if peripheral AVP administration increases heat loss from the tail. METHODS：The core temperature and tail skin temperature in adult male Sprague-Dawley rats at three different ambient temperatures (12 ℃, 22 ℃ and 32 ℃) were monitored by wireless telemetry. The rats were intraperitoneally injected with AVP (10 μg/kg) or vasopressin V1a receptor antagonist (30 μg/kg) at 10:00 AM. The diameters of microvessels in the spinotrapezius muscle and the grooming behavior in the rats were also observed after treatment with AVP or vasopressin V1a receptor antagonist. RESULTS：AVP-induced hypothermia in the rats at three ambient temperatures was accompanied by a decrease in tail skin temperature. V1a receptor antagonist attenuated the hypothermia and the decrease in tail skin temperature induced by AVP (10 μg/kg). AVP induced significant constriction of the microvessels in the spinotrapezius muscle. AVP also enhanced the grooming behavior (salivary grooming) in the rats and this effect was inhibited by peripheral administration of vasopressin V1a receptor antagonist. Endogenous AVP did not mediate the heat loss from the tail in normal rats. CONCLUSION：Peripheral AVP induces hypothermia in rats. It does not lower the set point of body temperature, and its hypothermic effect may attribute to the suppression of thermoregulatory heat production and the increase in salivary grooming (saliva spreading for evaporative heat loss).     

“2006中国蔬菜产业可持续发展研讨会”在武汉召开

由中国园艺学会主办，湖北省园艺学会、国家蔬菜改良中心华中分中心、华中农业大学园艺林学学院共同承办的“2006中国蔬菜产业可持续发展研讨会”于2006年4月13-15日在湖北武汉华中农业大学举行，来自全国17个省（市）和自治区47个单位的近120名代表出席这次全国性会议。会议开幕式由中国园艺学会蔬菜专业委员会主任、中国农业科学院蔬菜花卉研究所副所长孙日飞研究员主持。华中农业大学副校长李名家教授、武汉市张学忙副市长、科技部农村司魏勤芳处长、农业部科技司刘艳处长、武汉市科协黄和平主席和中国园艺学会理事长方智远院士先后致辞。     

Role of central PGE2 on sympathetic excitation in chronic heart failure

AIM: To observe the effect of central prostaglandin E₂ (PGE₂) on sympathetic activation in chronic heart failure (CHF) and to explore the underlying mechanism. METHODS: Male SD rats were subjected to coronary artery ligation to induce heart failure (HF), and the intracerebroventricular infusion was performed by osmotic pump continuously. The rats in sham group and HF group were given artificial cerebrospinal fluid (0.25 μL/h). The rats in HF plus treatment group was given celecoxib (CLB; 20 mg/h). After 4 weeks, the levels of PGE₂ in cerebrospinal fluid (CSF), the sympathetic nerve excitability and cardiac function were measured, and the changes of corticotropin-hormone releasing hormone (CRH)-containing neurons activation and neurotransmitter contents in the hypothalamic paraventricular nucleus (PVN) were also determined. RESULTS: Compared with the sham-operated rats, the HF rats had raised level of PGE₂ in CSF, up-regulated renal sympathetic nerve activity and plasma norepinephrine, increased left ventricular end diastolic pressure, lung-to-body weight and right ventricular-to-body weight ratios, and decreased maximal increase and decreased rate of left ventricular pressure (P<0.05). In addition, the number of CRH positive neurons in PVN and the level of plasma adrenocorticotropic hormone were higher in HF rats than those in sham-operated rats (P<0.05). After administration of CLB into the lateral ventricle of HF rats, the contents of PGE₂ in CSF were significantly reduced, the number of activation CRH neurons in PVN was decreased, the excitability of sympathetic nerves was down-regulated and cardiac function was improved (P<0.05). Compared with the sham-operated rats, the content of glutamic acid in PVN of HF rats was increased, the content of γ-aminobutyric acid and the number of glutamate decarboxylase 67-positive neurons were decreased (P<0.05). After the CLB was given, the above indexes were reversed (P<0.05). CONCLUSION: These findings indicate that in CHF, the increased central PGE₂ may activate CRH-containing PVN neurons and contribute to the augmented sympathetic drive possibly by modulating the neurotransmitters within the PVN.     

同源四倍体玫瑰香葡萄嫩枝扦插不定根发生过程中内源激素的变化

 以葡萄同源四倍体玫瑰香和其二倍体玫瑰香母株的嫩枝插条为试材, 研究了扦插生根过程中(0～18 d) 生根部位皮层的内源激素含量变化。结果表明: 玫瑰香葡萄同源加倍以后, 不仅改变了不同时期插条生根部位皮层的内源激素水平, 也改变了该部位对外施NAA的反应。在不定根诱导期( 0～3 d) ,促进生根的生长素水平下降, 抑制生根的脱落酸和赤霉素含量上升, 生长素与脱落酸和赤霉素的比值下降;应用NAA处理以后, 在根原基诱导期(0～3 d) , 赤霉素、玉米素和玉米素核苷含量不降反升, 改变了内源激素的整体变化态势。分析认为, 同源加倍后嫩枝插条生根部位内源激素的代谢变化是造成其生根能力降低的主要原因之一。     

Effects of astragaloside on the levels of sex hormone and oxidative stress injury in rats with polycystic ovary syndrome

AIM To investigate the effects of astragaloside on the levels of sex hormone and oxidative stress in rats with polycystic ovary syndrome （PCOS）. METHODS Female SD rats （n=60） were randomly divided into normal control group, model group, Diane-35 （0.339 2 mg/kg） group, low dose astragaloside （12.5 mg/kg） group and high dose astragaloside （50 mg/kg） group, with 12 rats in each group. The PCOS model was induced by letrozole （1 mg/kg）, which was administered by gavage once a day for 3 weeks. After administration, the estrus cycle of the rats was observed by vaginal smear, and the ovarian index was calculated. HE staining was used to observe the histopathological changes of the ovaries. Serum levels of the sex hormones testosterone （T）, estradiol （E₂）, luteinizing hormone （LH） and follicle-stimulating hormone （FSH） were measured by ELISA. The levels of superoxide dismutase （SOD）, malondialdehyde （MDA） and glutathione peroxidase （GSH-Px） in serum and ovarian tissue were detected by colorimetry, and the protein levels of steroidogenetic acute regulatory protein （StAR） and apoptosis-related proteins cleaved caspase-3, Bax and Bcl-2 in ovarian tissue were detected by Western blot. RESULT Compared with control group, the oestrous cycle of the rats in model group was disorder, and the ovarian index was increased, ovary was polycystic. The serum levels of T, LH and MDAwere significantly increased （P<0.05）, while the contents of E2, FSH and the activities of GSH-Px and SOD were significantly decreased （P<0.05）. The levels of MDA, StAR, cleaved caspase-3 and Bax proteins in ovarian tissue were significantly up-regulated （P<0.05）. GSH-Px and SOD activities and Bcl-2 protein levels were significantly down-regulated （P<0.05）. CONCLUSION Astragalosideeffectively balances the levels of sex hormone in PCOS rats and relieves the oxidative stress injury, the mechanism may be related to the inhibition of StAR expression.     

外施GA、MeJA、IAA、SA和KT对番茄表皮毛发生的作用

以番茄品种‘大量5号’和多茸毛突变品系‘3-071’为试材,通过喷施外源GA、MeJA、IAA、SA、KT处理幼苗,每3d 1次,取样进行内源激素测定和体视显微镜观察,研究不同植物生长调节剂及不同浓度对番茄表皮毛密度及类型的影响。结果表明,喷施各浓度梯度GA、MeJA和IAA均提高了两种番茄内源GA、MeJA、IAA含量,降低了SA、KT含量,同时番茄表皮毛Ⅳ、Ⅵ型显著增加。其中0.350 mg·L~(-1) GA、0.020 mg·L~(-1) Me JA处理对Ⅳ型表皮毛促进效果最显著;35.000 mg·L~(-1) GA、0.200mg·L~(-1) Me JA处理对Ⅵ型表皮毛促进效果最显著。各浓度IAA对两种番茄品种Ⅳ、Ⅵ型表皮毛发生均有显著的促进作用。外源KT促进内源SA、KT合成,抑制GA、MeJA、IAA的合成,对Ⅰ、Ⅳ型表皮毛发生有极显著的促进作用,对Ⅵ型表皮毛的发生有抑制作用,其中21.300 mg·L~(-1) KT对两种番茄对Ⅰ、Ⅳ、Ⅵ型表皮毛作用效果最显著。外源SA降低内源GA、MeJA、IAA含量,提高内源SA、KT含量。喷施SA对番茄Ⅰ、Ⅳ、Ⅵ型表皮毛发生有显著抑制作用,其中1.500 mg·L~(-1) SA处理抑制作用最显著。据此推测,外源植物生长调节剂通过影响各内源激素的含量,从而调控番茄表皮毛发生。