慢性镉负荷雄性大鼠的睾丸及生殖内分泌功能活动

选择健康SD雄性成年大鼠60只,随机分成对照组（C组）、镉负荷中剂量组（M组）和镉负荷高剂量组（H组）,每天分别饲喂含镉0,5,10mg/kg的大鼠全价饲料,连续6周,研究了镉负荷对大鼠睾丸及生殖内分泌功能活动的影响。结果显示：在整个实验期内,M和H组大鼠睾丸组织中的镉含量极明显上升,锌含量销有下降,与对照组差异不显著;血浆镉、锌含量虽分别表现稍有升高和下降,但与对照组比较无明显差异;H组睾丸精子头计数和每日精子生成量在镉负荷第3周极显著下降,第6周时,M和H组均极明显低于对照组;在整个实验期内,H组大鼠ALP活明显低于C组;LDH－X活性在M和H组大鼠均极明显低于C组;M和H组血浆T水平下降,均低于或显著低于C组;3组间的FSH和LH水平无明显差异。结果提示：慢性镉负荷在睾丸组织中逐步蓄积可引起睾丸一些酶活性改变、精子生成减少及内分泌功能活动低下。     

Chlorogenic acid modifies plasma and liver concentrations of: cholesterol,triacylglycerol, and minerals in (fa/fa) Zucker rats

Chlorogenic acid, a phenolic compound found ubiquitously in plants, is an in vitro antioxidant and metal chelator. Some derivatives of chlorogenic acid are hypoglycemic agents and may affect lipid metabolism. Concentrations of cholesterol and triacylglycerols are of interest due to their association with diseases such as non-insulin-dependent-diabetes- mellitus and obese insulin resistance. As little is known about the effects of chlorogenic acid in vivo, studies using obese, hyperlipidemic, and insulin resistant (fa/fa) Zucker rats were conducted to test the effect of chlorogenic acid on fasting plasma glucose, plasma and liver triacylglycerols and cholesterol concentrations. Aditionally, the effects of chlorogenic acid on selected mineral concentrations in plasma, spleen, and liver were determined. Rats were implanted with jugular vein catheters. Chlorogenic acid was infused (5 mg/Kg body weight/day) for 3 weeks via intravenous infusion. Chlorogenic acid did not promote sustained hypoglycemia and significantly lowered the postprandial peak response to a glucose challenge when compared to the same group of rats before Chlorogenic acid treatment. In Chlorogenic acid-treated rats, fasting plasma cholesterol and triacylglycerols concentrations significantly decreased by 44% and 58% respectively, as did in liver triacylglycerols concentrations (24%). We did not find differences (p > 0.05) in adipose triacylglycerols concentration. Significant differences (p < 0.05) in the plasma, liver, and spleen concentration of selected minerals were found in chlorogenic acid-treated rats. In vivo, chlorogenic acid was found to improve glucose tolerance, decreased some plasma and liver lipids, and improve mineral pool distribution under the conditions of this study.     

急性脊髓损伤后大鼠电刺激运动诱发电位的变化

目的：比较不同程度脊髓损伤（SCI）与运动诱发电位（MEP）变化之间的关系,探索MEP检查在SCI早期诊断及预后中的价值。方法：27只雄性SD大鼠以改良Allen‘s打击法致伤T8－T9脊髓,按打击冲量随机分为空白对照组（n=5),SCI A组（50gcf,n=8),SCI B组（70gcf,n=8)和SCI C组（100gcf,n=6),采用单极经皮层电刺激,分别于损伤前、伤后即刻、15min、30min、1h、3h和6h连续观察scMEP变化,并计算脊髓出血坏死区域占脊髓横截面积的比率。结果：对照组MEP无显著改变,SCI A组和SCI B组动物MEP早成份波幅立即减低或消失,以后有所恢复,晚成份波消失后未再出现。SCI C组动物除2只大鼠SCI后MEP仍有所恢复外,其余动物再未出现MEP波。脊髓损伤随打击冲量增大而增加,与伤后1h scMEP最大波幅呈显著相关（r=-0.821)。结论：SCI后scMEP的变化程度与打击冲量和脊髓病理损伤面积相关,提示scMEP可以作为一种脊髓功能检测的客观指标。     

Involvement of Accessory Neurosecretory Nuclei of Hypothalamus in the Formation of Hypothalamohypohysial System during Prenatal and Postnatal Development in Rats

We studied the development of direct axonal connections of the accessory neurosecretory hypothalamic nuclei with the posterior pituitary lobe on the fixed rat brain from day 15 of embryogenesis until day 10 of postnatal development using the retrograde diffusion method of the lipophilic fluorescent carbocyanine dye 1,1"-dioctadecyl-3,3,3",3"-tetramethylindocarbocyanine perchlorate along the neuronal membranes. The marker was applied onto the posterior pituitary lobe and, after incubation in a fixative, fluorescing bodies of nerve cells were visualized in the hypothalamus. Neuronal axons of the retrochiasmatic nucleus were the first of the accessory nuclei to ingrow in the posterior pituitary lobe (on days 16–17 of embryogenesis). Neurons of the circular and dorsolateral nuclei and the nuclei of the median bundle of the forebrain sent their axons to the posterior pituitary lobe starting from the first days of postnatal development. No direct connections of the anterior commissure and perifornical accessory nuclei with the posterior pituitary lobe were found in perinatal development. These facts are discussed in the light of concepts about the different functional role of accessory peptidergic hypothalamic nuclei in rats.     

Involvement of 5-HT(2A/2B/2C) receptors on memory formation: simple agonism,antagonism, or inverse agonism?

1. The 5-HT₂ receptors subdivision into the 5-HT_2A/2B/2C subtypes along with the advent of the selective antagonists has allowed a more detailed investigation on the role and therapeutic significance of these subtypes in cognitive functions. The present study further analyzed the 5-HT₂ receptors role on memory consolidation.2. The SB-200646 (a selective 5-HT_2B/2C receptor antagonist) and LY215840 (a nonselective 5-HT_2/7 receptor antagonist) posttraining administration had no effect on an autoshaped memory consolidation. However, both drugs significantly and differentially antagonized the memory impairments induced by 1-(3-chlorophenyl)piperazine (mCPP), 1-naphtyl-piperazine (1-NP), mesulergine, or N-(3-trifluoromethylphenyl) piperazine (TFMPP).3. In contrast, SB-200646 failed to modify the facilitatory procognitive effect produced by (±)-2,5-dimethoxy-4-iodoamphetamine (DOI) or ketanserin, which were sensitive to MDL100907 (a selective 5-HT_2A receptor antagonist) and to a LY215840 high dose.4. Finally, SB-200646 reversed the learning deficit induced by dizocilpine, but not that by scopolamine; while SB-200646 and MDL100907 coadministration reversed memory deficits induced by both drugs.5. It is suggested that 5-HT_2B/2C receptors might be involved on memory formation probably mediating a suppressive or constraining action. Whether the drug-induced memory impairments in this study are explained by simple agonism, antagonism, or inverse agonism at 5-HT₂ receptors remains unclear at this time.6. Notably, the 5-HT₂ receptor subtypes blockade may provide some benefit to reverse poor memory consolidation conditions associated with decreased cholinergic, glutamatergic, and/or serotonergic neurotransmission.     

Infant animal model of pulmonary mycotoxicosis induced by Stachybotrys chartarum

In recent years cases of often fatal pulmonary hemorrhage in infants have been associated with water damaged homes and the toxigenic fungusStachybotrys chartarum. The fungal spores contain mycotoxins which could be injurious to the rapidly developing lung. In order to understand the developmental pathophysiology of this disease we developed an infant rat model of stachybotrytoxicosis describing the effects of fungal spores on survival, growth, histopathology of the lung and respiration. Conidia ofS. chartarum were instilled intratracheally (1.0–8.0 × 10⁵/gm wt.) in 4-dold Sprague-Dawley rat pups. Two control groups received either sterile PBS or a suspension of spores extensively extracted with ethanol to remove toxins. Lethal dose response was determined (LD₅₀ = 2.7 × 10⁵ spores/gm wt.). All dead pups had extensively hemorrhagic lungs. Growth of surviving animals was impaired in a dose-dependent manner. Changes of pulmonary function parameters in rats treated with 1.1 × 10⁵ spores/g were consistent with an increased respiratory resistance. Histology of lungs revealed fresh hemorrhage, sparse hemosiderin-laden macrophages, and evidence of inflammation including thickened alveolar septa infiltrated by lymphocytes and mononuclear cells and intra-alveolar macrophages. Significant increases (p = 0.001) in numbers of macrophages (2-fold), lymphocytes (5-fold) and neutrophils (7-fold) were found in BAL fluid. Hemoglobin was elevated 2-fold (p = 0.004). Proinflammatory mediator IL-1β increased more than 6-fold and TNF-α30-fold (p = 0.001). Extracted spores had a minimal effect on all examined parameters in BAL fluid indicating that mycotoxins are primarily responsible for the hemorrhagic and inflammatory response. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of Nigella sativa L. and Urtica dioica L. on selected mineral status and hematological values in CCl4-treated rats

This study was designed to investigate the effects of Nigella sativa L. (NS), known as black seed, or/and Urtica dioica L. (UD), known as stinging nettle root, treatments on serum Na, K, Cl, and Ca levels and some hematological values of CCl₄-treated rats. Sixty healthy male Sprague-Dawley rats, weighing 250–300 g, were randomly allotted into 1 of 4 experimental groups: A (CCl₄-only treated), B (CCl₄+UD treated), C (CCl₄+NS treated), and D (CCl₄+UD+NS treated), each containing 15 animals. All groups received CCl₄ (0.8 mL/kg of body weight, subcutaneously, twice a week for 90 d starting d 1). In addition, B, C, and D groups also received the daily ip injection of 0.2 mL/kg NS and/or 2 mL/kg UD oils for 45 d starting d 46. Group A, on the other hand, received only 2 mL/kg normal saline solution for 45 d starting d 46. Blood samples for the biochemical analysis were taken by cardiac puncture from five randomly chosen rats in each treatment group at the beginning, d 45, and d 90 of the experiment. The CCl₄ treatment for 45 d significantly (p<0.05) increased the serum K and Ca and decreased (p<0.05) the red blood cell count (RBC), white blood cell count (WBC), packed cell volume (PCV), and Hb levels without changing (p>0.05) the serum Na and Cl levels. NS or UD treatments (alone or combination) for 45 d starting d 46 significantly (p<0.05) decreased the elevated serum K and Ca levels and also increased (p<0.05) the reduced RBC, WBC, PCV, and Hb levels. It is concluded that NS and/or UD treatments might ameliorate the CCl₄-induced disturbances of anemia, some minerals, and body’s defense mechanism in CCl₄-treated rats.     

Effects of zinc and melatonin deficiency on testicular tissue of rats

The present study was designed to investigate the effects of zinc and/or melatonin deficiency on rat testes. A total of 24 adult male Sprague-Dawley rats were used in this study. The rats were divided into four groups of six rats each, as follows: (I) controls, (II) zinc deficient, (III) pinealectomized, zinc normal, and (IV) pinealectomized, zinc deficient. The plasma zinc levels in the control group were higher than in all the other groups (p<0.01), and those of the zinc-deficient groups II and IV were significantly lower than for group III (p<0.01). The melatonin levels in the controls were also significantly higher than for all other groups (p<0.01) There was no significant difference in sperm production between the controls and the group of animals that had no epiphysis. A significant suppression was observed in the spermatogenetic activity of the zinc-deficient groups (p<0.01). The suppression was higher in group II than in group IV. These results indicate that testicular damage caused by zinc deficiency may be reduced by melatonin deficiency.     

Pulsed electromagnetic fields prevent osteoporosis in an ovariectomized female rat model: a prostaglandin E2-associated process

With the use of Helmholtz coils and pulsed electromagnetic field (PEMF) stimulators to generate uniform time varying electromagnetic fields, the effects of extremely low frequency electromagnetic fields on osteoporosis and serum prostaglandin E(2) (PGE(2)) concentration were investigated in bilaterally ovariectomized rats. Thirty-five 3 month old female Sprague-Dawley rats were randomly divided into five different groups: intact (INT), ovariectomy (OVX), aspirin treated (ASP), PEMF stimulation (PEMF + OVX), and PEMF stimulation with aspirin (PEMF + ASP) groups. All rats were subjected to bilateral ovariectomy except those in INT group. Histomorphometric analyses showed that PEMF stimulation augmented and restored proximal tibial metaphyseal trabecular bone mass (increased hard tissue percentage, bone volume percentage, and trabecular number) and architecture (increased trabecular perimeter, trabecular thickness, and decreased trabecular separation) in both PEMF + OVX and PEMF + ASP. Trabecular bone mass of PEMF + OVX rats after PEMF stimulation for 30 days was restored to levels of age matched INT rats. PEMF exposure also attenuated the higher serum PGE(2) concentrations of OVX rats and restored it to levels of INT rats. These experiments demonstrated that extremely low intensity, low frequency, single pulse electromagnetic fields significantly suppressed the trabecular bone loss and restored the trabecular bone structure in bilateral ovariectomized rats. We, therefore, conclude that PEMF may be useful in the prevention of osteoporosis resulting from ovariectomy and that PGE(2) might relate to these preventive effects.     

Functional and structural characterization of anti-β1-adrenoceptor autoantibodies of spontaneously hypertensive rats

Eighteen month old spontaneously hypertensive rats (SHR-rats) showed myocardial dysfunction and autoantibodies directed against the ₁-adrenoceptor similarly as known in human dilated cardiomyopathy or Chagas' disease. The agonist-like antibodies were able to activate the ₁-adrenoceptor mediated signal transduction cascade in cultured rat cardiomyocytes and induced a long-lasting stimulatory effect resulting in a harmful adrenergic overdrive. The antibodies recognized an epitope of the second extracellular loop of the ₁-adrenoceptor identical to that epitope identified in Chagas' disease. In conclusion, our assumption is supported that old SHR-rat are an useful animal model for investigating the role of anti-₁-adrenoceptor antibodies in the induction of human cardiomyopathy.