金雀异黄酮对去卵巢大鼠骨质疏松性骨折愈合的实验研究

目的研究金雀异黄酮对去势大鼠发生骨质疏松性骨折愈合的影响。方法成年SD大鼠卵巢摘除后3个月开始制作左侧股骨中段闭合骨折内固定手术模型,并分为骨折组和骨折用药组,每组各20只骨折用药组注射金雀异黄酮,分别于大鼠折骨后15和30dX射线摄片、检测血清骨碱性磷酸酶(B鄄ALP)、I型前胶原羧基端肽(PICP)、骨钙素(BGP)等骨形成生化指标,并与骨折组比较。结果骨折用药组骨痂形成量多,骨折线模糊或消失,B鄄ALP、PICP和BGP水平显著下降(P<0.01)。结论金雀异黄酮可调节骨代谢,促进骨形成,加快大鼠骨折愈合的作用。     

Effects of dietary equol administration on ovariectomy induced bone loss in Sprague-Dawley rats

Oestrogen deficiency leads to a considerable bone loss, thus, osteopenia and osteoporosis are serious complications after menopause. OBJECTIVES: To evaluate the effects of a daidzein metabolite equol on bone mass density (BMD) and markers of bone remodelling in an ovariectomized (ovx) rat model of postmenopausal bone loss and compare them with the effects of 17beta-estradiol. METHODS: Twenty-eight female Sprague-Dawley rats were ovx and fed soy-free chow only (control group, n = 8), or with the addition of oestradiol-3 benzoate (E2B) (10mg/kg, n = 10) or equol (400 mg/kg, n = 10). At baseline and after 6-week treatment period, proximal tibia and lumbar spine BMD were measured using computer tomography. Animals were then sacrificed, blood was collected and uteri were removed. RESULTS: Similarly to E2B, dietary equol decreased weight gain and showed mild uterotropic activity. E2B attenuated ovx induced BMD loss at proximal tibia whereas equol had no effect. At lumbar spine, however, equol not only attenuated trabecular bone loss but also increased its density. This effect was also apparent in animals treated with E2B. Cortical BMD at proximal tibia and lumbar spine were not very much influenced by ovx and treatment with E2B or equol did not induce significant changes at these sites. Plasma osteocalcin and type I collagen fragments (cross-laps) in equol treated animals did not differ from the controls whereas in E2B treated animals they were both significantly decreased. CONCLUSIONS: In spite of its mild uterotropic potential, dietary equol shows limited bone sparing effects in ovx rats.     

Prolame ameliorates anxiety and spatial learning and memory impairment induced by ovariectomy in rats

N-(3-hydroxy-1, 3, 5 (10) estratrien-17beta-yl)-3-hydroxypropylamine (17β aminoestrogen, prolame) is a steroidal compound with weak estrogen-related trophic-proliferative effects in uterus. Contrasting with 17β-estradiol (E2) pro-coagulant effects, this compound has high anticoagulant and antiplatelet effects. It has been extensively demonstrated that E2 plays important roles in brain function. However, prolame's influence on central nervous system has not been documented. In this study, we evaluated the effects of prolame replacement in young ovariectomized rats on spatial learning and memory and anxiety, correlating pyramidal cell dendritic spine density changes and neuronal nitric oxide synthase (nNOS) expression in the hippocampus. Ovariectomized young rats were treated with prolame for 4 weeks. Three other groups were used as physiological, pathological, and pharmacological references as follow: gonadally intact cycling females, ovariectomized, and ovariectomized with 17β-estradiol treatment respectively, for the same time period. Experiment 1 investigated the behavioral effects of prolame on anxiety and spatial learning using elevated plus maze (EPM) and Morris water maze (MWM) paradigms respectively. Experiment 2 studied the dendritic spine density and neuronal nitric oxide synthase expression in the hippocampus of the 4 experimental groups. Similar to estradiol, prolame reversed the anxiogenic effects of ovariectomy, evaluated by EPM, and enhanced MWM performance to the level of gonadally intact subjects. Hippocampi from prolame-treated rats exhibited enhanced nNOS immunoreactivity and its relocation in dendritic compartments, as well as recovery of dendritic spine density loss in pyramidal neurons. Hence, prolame may provide an alternative option for ameliorating neurological symptoms caused by surgical menopause.     

Comparison of osteopenic changes in cancellous bone induced by ovariectomy and/or immobilization in adult rats

Background: Ovariectomy (OVX) and immobilization (IMM) in rats are useful models of osteopenia, replicating some aspects of osteoporosis in humans. The purpose of this study was to compare changes in cancellous bone after OVX and/or IMM. Methods: Differences in cancellous bone were determined at 6 and 12 weeks after OVX or IMM. Comparisons were also made when rats were ovariectomized or immobilized for 6 weeks and then immobilized (OVX/IMM) and ovariectomized (IMM/OVX), respectively, for 6 more weeks. The femurs were used to determine bone mineral content (BMC) using single photon absorptiometry (SPA) and for scanning electron microscopy (SEM). Tibias were collected for microradiography, image analysis, and histomorphometry of metaphyseal cancellous bone. Results: Six and 12 weeks after OVX, there was less cancellous bone mass, compared with controls, as indicated by SPA, SEM, microradiography, image analyses, and histomorphometry. Bone was lost primarily from the central metaphyseal regions in the OVX animals, whereas the loss occurred throughout the metaphyses in the IMM animals. There were more rodlike bone spicules and fewer platelike trabecule in the OVX and IMM groups compared with controls. Differences in the structural aspects of the cancellous bone, including differences in the types of bone struts and marrow star volumes, indicated less trabecular connectivity and greater trabecular separation in the OVX and IMM animals, compared with controls. Endochondral growth indices in the IMM groups tended to be less, whereas the OVX groups tended to be greater than controls. Cancellous bone formation rates were generally greater in the OVX groups but less in the IMM groups compared with controls. Osteoclastic resorption surfaces were substantially elevated in the IMM and OVX groups, particularly the IMM groups. Changes reflecting OVX and IMM, independently, were apparent in the OVX/IMM and IMM/OVX groups and indices of osteopenia were different from controls, including less bone mass, trabecular connectivity, and greater trabecular separation, bone turnover rates, and osteoclastic surface. Conclusions: These results demonstrate differences in the osteopenic changes that occur in cancellous bone following OVX or IMM. The changes were generally more dramatic in the IMM than in the OVX animals. When OVX and IMM were applied in combination, the osteopenic changes are particularly severe, emphasizing the importance of mechanical usage even with a deficiency of gonadal hormones. © 1994 Wiley-Liss, Inc.     

The effect of selenium on hepatocarcinogenesis of rats induced by aflatoxin B1

This experiment was designed to observe the effects of 3 ppm and 6 ppm selenium in water on preneoplastic lesions in liver and hepatocarcinogenesis induced by AFB1. In the group administered selenium, the number of hyperplastic foci and enzyme altered foci was much less than that in the AFB1 group. From the 52nd to 79th week, cancers were observed in 11 of 18 rats in the AFB1 group, while none was found in the selenium treated groups. These results reveal that selenium can inhibit the formation of hyperplastic foci and enzyme--altered foci as well as hepatocarcinogenesis induced by AFB1, but selenium can neither prevent the enlargement nor accelerate the regression of the foci already developed after administration of carcinogens. Additionally, toxic effect of selenium was found in 6 ppm selenium group; the number and size of foci were greater in 6 ppm selenium group than those in 3 ppm group. Therefore, adequate amount of selenium is probably the link to achieve better inhibitory effect.     

卵巢切除对大鼠骨组织结构改变的影响

目的：探讨卵巢切除对大鼠骨组织形态学改变的影响。方法：将１８只３月龄雌性大鼠随机分为卵巢切除组及假手术组（对照组）。术后３周处死两组大鼠，获取股骨远端１／３处骨，分别进行石蜡包埋，塑料包埋切片及扫描电镜观察。结果：卵巢切除可引起大鼠骨小梁变细、中断，骨小梁表面钙盐沉积减少。结论：卵巢切除可使大鼠骨吸收增加，影响骨的稳定性，增加骨折发生的危险性。     

白藜芦醇对高脂饮食去卵巢肥胖大鼠海马组织脑源性神经营养因子水平的影响

 目的：探讨去卵巢联合高脂饮食诱导的肥胖大鼠海马组织中脑源性神经营养因子（BDNF）、雌激素受体α (ERα)和雌激素受体β (ERβ) 表达的变化,同时观察白藜芦醇对这些改变的影响。方法：50只3月龄雌性Wistar大鼠随机分为5组：假手术普通饮食对照（C）组、假手术高脂饮食（H）组、单纯去卵巢（O）组、去卵巢高脂饮食（O+H）组和白藜芦醇（40 mg·kg-1·d-1）+去卵巢高脂饮食(O+H+R)组。3月后抽取股动脉血检测血清雌二醇（E2）、总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）和低密度脂蛋白胆固醇(LDL-C)含量;实时荧光定量PCR法检测海马BDNF、ERα和ERβ mRNA表达,蛋白免疫印迹法及ELISA法分别检测海马BDNF蛋白含量。结果：与C组比较,H组大鼠血清TC和LDL-C含量升高,海马BDNF水平显著降低（P<0.05或P<0.01）,O组大鼠血清E2水平降低,TC含量升高,海马BDNF 水平及ERα、ERβ mRNA表达均明显下降（P<0.05或P<0.01）;O+H组大鼠血清TC含量升高,HDL-C水平降低,海马BDNF 水平降低,与C组、H组和O组比较均有显著差异（P<0.05或P<0.01）,海马ERα和ERβ mRNA表达下降,与C组和H组比较差异显著（P<0.05或P<0.01）;O+H+R组大鼠血清E2水平升高,TC含量降低,海马ERα和ERβ mRNA表达水平及BDNF含量均明显增加,与O+H组比较有显著差异（P<0.05或P<0.01）。结论：去卵巢联合高脂饮食显著降低大鼠海马ERα和ERβ mRNA表达及BDNF水平,而白藜芦醇能够明显改善绝经后肥胖大鼠的血脂水平,上调海马ERα和ERβ mRNA表达,增加海马BDNF水平。     

The antifibrogenic effect of etanercept on development of liver cirrhosis induced by thioacetamide in rats

Liver cirrhosis is an elevating cause of morbidity and mortality worldwide. TNF-α/TNF-R1 signal is implicated in progression of many liver diseases. This study provides histological and ultrastructural view that clarifies the effect of etanercept, a TNF-α inhibitor, on development of thioacetamide (TAA)-induced liver cirrhosis and the accompanied hemosiderosis in rats, highlighting the implication and distribution pattern of hepatic TNF-R1. Sixty male albino rats (Rattus norvegicus) were equally randomized into three groups. Group I served as the control. Liver cirrhosis was triggered in the other two groups by intraperitoneal injection of TAA twice a week for five months. Group II received TAA only, while group III subcutaneously injected with etanercept one hour before TAA, along five months. At the end of the experiment, blood was collected for biochemical analysis and livers were excised for histological, immunohistochemical, and electron microscopical preparations. Rats treated with TAA only developed hepatic cirrhosis accompanied by massive deposition of hemosiderin; strong and widespread expression of hepatic TNF-R1 in sinusoidal endothelial cells (SECs), Kupffer cells (KCs), and many hepatocytes; and frequent appearance of fibrogenic, plasma, and mast cells, at the ultrastructural level. By contrast, administration of etanercept diminished the expression of TNF-R1, attenuated the accumulation of collagen and hemosiderin, and preserved the hepatic histoarchitecture. In conclusion, TNF-α signal via TNF-R1 may be implicated in the mechanism of fibrogenesis and the associated hemosiderosis. Etanercept may provide a promising therapeutic approach not only for attenuating the progression of fibrogenesis, but also for hepatic iron overload-associated disorders.     

The effect of methylprednisolone on treatment in rats with induced sepsis

In this study, an appropriate sepsis model was created in rats. Additionally, the effects of steroid treatments on survival, in connection with antibiotic treatment, were investigated. The sepsis model performed via intraperitoneal injection of 3 ml/kg fecal suspension was determined as the most appropriate model for our study. Fifteen rats were used to investigate the effect of piperacillin–tazobactam on sepsis treatment. Forty-five randomly selected rats were used to investigate the efficacy of the antibiotic-plus-steroid combination. The rats were divided into three groups of 15 rats each. Twelve hours after the administration of fecal suspension, methylprednisolone (MP) at the dose of 0.25, 0.5, and 2 mg/kg/day was given to each group, respectively, in addition to an antibiotic administered intravenously. In order to investigate the effect of steroids alone in the treatment of sepsis, 0.5 mg/kg/day MP was given intravenously to 15 rats, 12 h after the fecal suspension was administered. It was concluded that administration of MP alone shortens survival time in rats with sepsis, whereas antibiotic therapy alone increases survival time significantly in rats with sepsis. It was seen that the antibiotic-plus-steroid treatment increases survival significantly compared to rats with no treatment (p < 0.05). In addition, steroids, when added to an antibiotic treatment in sepsis, affect survival positively when compared to the group with antibiotic therapy alone, depending on the dose given. Although, not statistically significant, high doses decrease survival (p > 0.05), and very low doses increase survival and mean survival time (p > 0.05) on the basis of clinical observation and average life time. However, low doses were found to increase survival significantly (p < 0.05). We concluded that low-dose MP, in addition to the appropriate antibiotic therapy, is the optimal in the treatment of rats with intraabdominal sepsis.     

大鼠重饲对应激溃疡发生的保护作用

本研究的目的是确定重饲对饥饿大鼠束缚—寒冷应激性溃疡有否保护作用。实验证明,饥饿大鼠重饲2克大米,应激性溃疡的发生率明显少于对照组。如于重饲前2小时服消炎痛(5mg/kg),以阻断胃的PG合成,上述保护作用则不发生,提示重饲可能是通过促进胃PG合成起作用的。     

The effects of ovariectomy on the mechanical properties of skin in rats

OBJECTIVE: After menopause, observable changes occur in the physical characteristics of the human skin. These changes and their responses to various treatments can be assessed with non-invasive in-vivo mechanical tests. However, tests measuring breaking strength and tensile strengths can only be done ex-vivo, they require relatively higher quantities of skin and thus have generally been performed on animals. Mechanical changes in the skin of ovariectomized rats, an appropriate model for the study of postmenopausal period, have not been dealt with in the literature. In this study mechanical characteristics of the skin, such as breaking strength and tensile strength have been tested and studied histologically in ovariectomized rats. METHODS: Sixteen rats were divided into two groups, one undergoing ovariectomy and one control group undergoing a sham operation. Three months later, the rats were sacrificed and tensile properties of their back skins were tested with a tensometer and evaluated histologically. RESULTS AND CONCLUSION: Breaking strength, tensile strength and the Young's modulus have increased and the thickness of the subcutis has decreased in ovariectomized rats. This study should be tested by others, because of existence of some conflicts between available knowledge and the results, relating to postmenopausal skin changes.     

The effect of conjugated equine estrogens on ovariectomy-induced osteopenia in the rat

The effect of estrogen replacement on ovariectomy-induced bone loss was evaluated in mature Sprague-Dawley rats. Undecalcified tibia of ovariectomized rats were processed for quantitative histologic assessment of cancellous bone in longitudinal sections from the primary and secondary spongiosa of the proximal metaphysis. Bone content in tissue specimens was quantified as the parameter B. Ar, two-dimensional bone mineral area. Estrogen, supplied as orally administered conjugated equine estrogens, prevented bone loss through 6 weeks of treatment. The effect of conjugated equine estrogens was dose-dependent, with significant protection against bone loss observed at doses of 10 g/kg/day and higher.     

The effect of melatonin on morphological changes in liver induced by magnetic field exposure in rats

In this study, we aimed to investigate the possible effect of melatonin on morphological changes in liver induced by magnetic fields exposure. Thirty albino young male Wistar Albino rats were used in the study. They were divided into 3 groups. Control group (C) (n: 10) received daily intraperitoneal injections of saline (0.1 ml/100 g) containing 5% ethanol for two weeks. Only magnetic field exposed (MF) group (n: 10); only magnetic field exposed had daily intraperitoneal injections of physiologic saline (0.1 ml/100 g) containing 5% ethanol for two weeks. Magnetic field exposed and melatonin treated (MF+m) group (n: 10); melatonin was dissolved in ethanol with further dilution in physiological saline. The animals in this group were exposed magnetic fields for two weeks. The magnetic fields exposed animals had intraperitoneal single dose of 4 mg/kg melatonin (0.1 ml/100 g) at 10:00 o'clock daily for two weeks following magnetic fields exposure. We used commercial CB handheld portable transceiver, Midland (USA) labelled, of 4 Watts, 40 channel. This channel frequency has been measured 27.17 MHz with frequency counter. According to the IRPA exposure standards; for 27 MHz, for 6 min, exposure limit is 0.2 mW/cm2. This value is for General Public. For occupational exposure limit is 1 mW/cm2. We have to consider General Public exposure limit. Therefore our limit is 0.2 mW/cm2. In other words; in this study; our exposure is always over the recommended limit. All the animals were decapitated. Liver samples were fixed in buffered neutral formalin. Paraffin sections were dyed with hematoxylen-eosin. Sections were examined under light microscopy. In MF group; sinusoidal dilatations, mixed cell infiltrations noticed in the periportal area, necrosis and vacuoler degeneration were determined in liver samples. However, parenchymal and stromal structures were observed to be prevented partially from effects of magnetic fields in melatonin treated group. In conclusion, it is suggested that melatonin has a mild preventive effect on magnetic field exposed changes in liver tissue in the rats.     

Short-term healing kinetics of cortical and cancellous bone osteopenia induced by unloading during the reloading period in young rats

 We investigated the short-term recuperation of bone mass during skeletal reloading after a period of unloading in young rats. One hind limb of 4-week-old rats was either unloaded irreversibly by sciatic neurectomy, or unloaded reversibly by external fixation. Other animals were sham-operated. After 9 days, the fixation-unloaded limbs were reloaded for 1–3 weeks and were compared with the hind limbs of age-matched unloaded (neurectomized) and sham-operated controls. Cortical and cancellous bone mass was measured using ashing and histomorphometry. Cortical bone mass (expressed as femoral dry and ash weight and tibial cortical bone area) was reduced in both unloaded groups and was accompanied by production of hypomineralized bone, as shown by a reduction in the percent ash of the dry weight. Cancellous bone mass (expressed as bone area and surface at the tibial metaphysis) was also reduced in both unloaded groups. Cortical bone mass deficit was greater in the fixation group than in the neurectomy group. Thereafter it increased in the neurectomy group despite a normal longitudinal growth rate, but returned to age-matched values in the reloaded group by 3 weeks. The changes in tibial cancellous bone mass were more pronounced but followed a similar pattern and normalized by 2 weeks. These data demonstrate that total unloading produced by external fixation causes a greater degree of bone mass deficit than partial unloading (produced by neurectomy); the rate of bone loss during unloading in the rat hind limb is more rapid than its recovery during reloading; and cancellous bone recuperates during the reloading phase faster than does cortical bone. Received: 11 February 1997 / Accepted: 28 May 1997     

代谢型谷氨酸受体5拮抗剂(MPEP)在大鼠颞下颌关节疼痛中的作用和可能机制

目的探讨应用代谢型谷氨酸受体5拮抗剂(MPEP)后,福尔马林致颞下颌关节疼痛大鼠三叉神经节内降钙素基因相关肽(CGRP)的表达变化,为临床颞下颌关节疼痛治疗提供实验依据。方法 SD大鼠36只,随机均分为4组,正常对照组(不做任何处理),阴性对照组(右侧颞下颌关节内注射50μl生理盐水),甲醛组(右侧颞下颌关节内注射50μl5%formalin),MPEP(2-甲基-6苯基乙炔嘧啶)组[25μlMPEP(5mmol/L)+50μl5%formalin]。将5%甲醛注入右侧颞下颌关节腔内,诱导大鼠颞下颌关节疼痛。计数各组大鼠60min内伤害性行为反应(包括刮擦头面部及缩头)。并利用免疫组织化学方法检测三叉神经节内CGRP的蛋白定位与表达。结果甲醛组大鼠搔刮头面部及缩头反应持续时间明显高于正常对照组及阴性对照组(P<0.05),MPEP组搔刮头面部及缩头等伤害性行为反应明显低于甲醛组(P<0.05)。免疫组化结果显示甲醛组、MPEP组三叉神经节内CGRP免疫反应阳性物质与正常对照组比较显著增加(P<0.05),生理盐水组与正常组比较无统计学差异(P>0.05),MPEP组与甲醛组比较CGRP免疫反应阳性物质明显降低(P<0.05)。结论代谢型谷氨酸受体5拮抗剂减轻福尔马林引起的大鼠颞下颌关节疼痛可能与其下调三叉神经节内CGRP的表达水平相关。     

The effect of cannabis on oxidative stress and neurodegeneration induced by intrastriatal rotenone injection in rats

We investigated the effect of cannabis treatment on the development of oxidative stress and nigrostriatal cell injury induced by intrastriatal rotenone injection in rats. Rotenone was injected into the right striatum at a concentration of 5 mM (3 μl/rat). The control rats received the vehicle (DMSO). Subsequently, the effect of Cannabis sativa extract treatment on rotenone toxicity was evaluated. Starting on the second day of rotenone injection, rats were treated with C. sativa extract (5, 10, or 15 mg/kg) (expressed as Δ⁹-tetrahydrocannabinol) subcutaneously (s.c.) once daily for 30 days. Biochemical markers of oxidative stress, malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide, paraoxonase 1 (PON1) activity, catalase activity, as well as tumor necrosis factor alpha (TNF-α), were determined in different brain areas after 30 days of rotenone treatment. Histopathology and immunohistochemical expression of tyrosine hydroxylase (TH), capase 3, and inducible nitric oxide synthase (iNOS) were also performed. Results showed that intrastriatal injection of rotenone resulted in increased brain oxidative stress in the cerebral cortex, striatum, hippocampus, midbrain, and cerebellum. MDA increased by 41.4–70 %, nitric oxide increased by 48.3–77.5 %, while GSH decreased by 25.0–34.2 %. PON1 and catalase activities decreased by 43.0–60.8 % and by 14.2–36 %, respectively, in these areas. Striatal TNF-α increased by 638.9 % of control value after rotenone injection. Rotenone induced motor deficits (decreased rearing activity). Rotenone caused marked nigrostriatal neurodegeneration, decreased TH immunoreactivity, and increased both iNOS and caspase 3 immunoreactivities in the striatum. Cannabis decreased brain oxidative stress and nitric oxide release induced by intrastriatal rotenone in several brain areas. Cannabis also decreased the elevated TNF-α in the striatum. Cannabis did not protect against the immunohistochemical changes in the striatum and substantia nigra or against neuronal degeneration induced by rotenone treatment. Collectively, these results indicated that the administration of cannabis did not protect against nigrostriatal damage caused by intrastriatal rotenone.