[Effects of endocrine disrupting compounds on hypothalamic-pituitary-gonadal axis and reproductive health a review]

Introduction: The hypothalamic-pituitary-gonadal [HPG] axis controls reproductive function. The hypothalamus secretes GnRH that is transported to the anterior pituitary gland to stimulate the release of the gonadotrophic hormones. Which act on the gonads to stimulate sexual maturation, gametogenesis and steroidogenesis. Although GnRH neurons are a key component of the HPG axis, other neurotransmitters or neuropeptides in the hypothalamus, such as glutamate, GABA, galanin, dopamine and kisspeptin have been suggested to be involved in the regulation of GnRH secretion. In addition to GnRH neurons, pituitary and gonads, some of these neuronal populations such kisspeptin are extremely sensitive to changes in the levels of steroid hormones and endocrine disrupting compounds [EDCs]. Several EDCs, such as pesticides, bisphenol A, phthalates, tamoxifen, phytoestrogens and mycoestrogens can interact with the female and male reproductive system function and lead to disruption of endocrine function. Reproductive system development and function may be susceptible to the effects of such EDCs. By far, the greatest concerns for the potential adverse effects of EDCs have focused on their deleterious impact on reproductive health. It has been demonstrated under laboratory conditions and epidemiological studies that EDCs can exert detrimental effects especially during hormonal critical periods such as fetal and neonatal periods on the reproductive system. This article reviews some evidence that EDCs can impair the HPG axis and reproductive function

Preparation of decellularized three dimentional scaffolds as the model for tissue engineering and their functional assessments in vitro application of blastema tissue

Tissue engineering is based on three main factors including scaffolds, cells and growth factors. Natural scaffolds derived from decellularized tissues and organs have been successfully used in tissue engineering. Decellularization studies have shown that natural scaffolds which maintain their main structure and properties could be a suitable tool for studying cellular behaviors and preparation of such scaffolds is an important part of future research in biology that may have extensive applications in regenerative medicine and tissue engineering. Blastema tissue which is produced after injuries in some organisms has embryonic cell characteristics, and can be a suitable model for evaluation of cell behaviors in various tissues. In this review, the process of decellularization, process involved in preparation of 3D scaffolds derived from extracellular matrix of various tissues including cartilage, bone, gingiva, aorta and bladder, and assessment of their interactions with blastema tissue under in vitro conditions are discussed

[ effects of hydro-alcoholic extract of launaea acanthodes on the blood, urine albumin and bilirubin levels in male hyperglycemic wistar rat]

Nowadays, diabetes and its related methbolic disorders are the main cause of end stage renal disease. The present study aimed to investigate the possible therapeutic effects of Launaea acanthodes hydro-alcoholic extract administration on the serum and urine albumin and bilirubin levels in hyperglycemic rats. Twenty-four male Wistar rats were randomly allocated into four groups; the control, hyperglycemic [STZ; 55 mg/kg], hyperglycemia+ insulin [STZ+Ins; 5 IU/kg/day] and hyperglycemia+extract [STZ+Ext; 150 mg/kg/day]. Blood and urine samples were taken at the end of the 2[nd] and 4[th] weeks of experiment and serum and urine albumin and bilirubin levels were assessed. Although compared to the control group in the 2[nd] week samples in which the serum levels of bilirubin in STZ and STZ+Ext groups were significantly increased, in the 4[th] week only STZ group samples showed significant differences. In the 4[th] week urine samples the level of albumin was remarkably increased in STZ and STZ+Ins while there was no significant difference in the STZ+Ext group samples. These results clearly indicate the beneficial effect of L. acanthodes extract adiminstration in prevention of albumin loss through urine in hyperglycemic status. Therefore it may be concluded that L. acanthodes could be effective in the treatment of metabolic disorders

[Investigating the anti-epileptic and sedative effects of hydroalcoholic extract of Melissa officinalis [Lemon balm] leaf on pentylenetetrazol induced epileptiform seizures in wistar rat]

Since long lasting administration of anti-seizure drugs produces undesirable side effects, many efforts have been made during recent decades to find and replace the chemical drugs by medicinal plants. The aim of present study was to study the antiepileptic [anti-seizure] effects of hydroalcoholic extract of Melissa officinalis on experimental epileptiform seizures, induced by pentylenetetrazol [PTZ] in Wistar rat. After normalization, rats in experimental groups 1, 2 and 3 were injected [i.p] 50, 80 and 120 mg/kg hydroalcoholic extract of Melissa officinalis, respectively. Control animals were injected extract solvent as the same manner. After 30 minutes all rats were injected [i.p] 80 mg/kg PTZ and then examined for epileptiform behaviors for the next 60 minutes. The rate of mortality during the next 24 hour was also recorded. In comparison with control group, in all experimental groups the latent period of tonic-clonic generalized seizure was significantly [P < 0.05] increased. Moreover, the mortality rate was decreased from 90% in control group to 30, 50 and 60% in experimental groups 1, 2 and 3, respectively. It can be concluded that hydroalcoholic extract of Melissa officinalis has potential sedative and anticonvulsant effects and probably exerts its effects through GABAergic system

Nitrous oxide levels in operating and recovery rooms of Iranian hospitals

Nitrous oxide [N[2]O] is the oldest anesthetic in routine clinical use and its occupational exposure is under regulation by many countries. As studies are lacking to demonstrate the status of nitrous oxide levels in operating and recovery rooms of Iranian hospitals, we aimed to study its level in teaching hospitals of Tehran University of Medical Sciences. During a 6-month period, we have measured the shift-long time weighted average concentration of N[2] O in 43 operating and 12 recovery rooms of teaching hospitals of Tehran University of Medical Sciences. The results show that the level of nitrous oxide in all hospitals is higher than the limits set by different countries and anesthetists are at higher risk of exposure. In addition, it was shown that installation of air ventilation could reduce not only the overall exposure level, but also the level of exposure of anesthetists in comparison with other personnel. The high nitrous oxide level in Iranian hospitals necessitates improvement of waste gas evacuation systems and regular monitoring to bring the concentration of this gas into the safe level

[Evaluating the protective effects of melissa officinalis on learning deficits of rat's offspring exposed to lead acetate during pre-and postnatal periods]

Lead contamination dramatically influences different body systems especially the central nervous system. Lead absorption during gestational period has deleterious effects on fetal differentiation and development and it may possibly result in learning deficits in adulthood. Recent studies have demonstrated positive effects of Melissa officinalis on memory improvement in some neural disorders. The aim of the present study is to investigate the protective effects of Melissa on learning deficits in lead acetate exposed rats. In this experimental study in department of Biology, Faculty of Sciences, Ferdowsi University of Mashhad [2008-2009], 40 mated Wistar rats were divided into 8 groups as follows: control, negative control [Pb], Melissa [M] and Pb+M, and each in 3 different subgroups. The treatment started from the 7th day of gestation and continued during pregnancy and lactation. The learning ability and memory retention of four months old offspring were tested by complex T-maze. The collected data was analyzed by the SPSS software using one-way ANOVA and Toki test. A significant difference was found between lead exposed group and other groups regarding the time to reach the goal and the number of errors; while there was no meaningful difference between the control and other experimental groups. In lead exposed rats, learning deficits were obviously noticed. Since there was meaningful difference between control and Pb+M subgroups, Melissa can possibly improve learning deficits in lead acetate exposed rats

[Morphometric study of the influence of hypo and hyperthyroidism on papillar myocytes at left ventricle of rats]

Thyroid gland affects many physiologic and metabolic activities .Thyroxine [T4] and its effective form [T3] regulate metabolism of tissues. These hormones affect the heart work with direct or indirect mechanisms. In the present study we investigated the effect of hypo and hyperthyroidism on rat heart. We used female Wistar rats [250-300 gr] in 3 groups [each consisted of 6]: Hyperthyroid rats were treated with thyroxine [1 mg/lit water for 20 days] hypothyroid rats were treated with propylthyoacil [PTU] [0.5 gr/lit water] and Control. Finally, histopathological and stereometric evidences were investigated in heart slides. Results showed that in papillar muscle of hyperthyroid rats, there were clear evidences of hypertrophy and increased capillary density. In hypohtyroid rats, however, changes were in opposite to hyperthyroid rats. Results revealed that during changes of hypo and hyperthyroidism, the metabolic changes are in accordance with cardiac hyperthrophy during hyperthyroidism and in opposite direction in hypothyroid rats

effect of plasma testosteron on epileptiform seizures induced by pentylen tetrazole [PTZ] in normal and gonadectomized male rats

It has been verified that androgene concentration in epileptic men who were treated with antiepileptic drugs is decreased and this results in a decrease in sexual activities in such patients. Although there : are many investigations regarding the effects of antileptic drugs on the rate of serum androgenes and particularly testosteron, little is known about the probable effects of androgenes on epileptic seizures. In this study the effects of plasma level of testosteron on epileptiform seizures in three cases [normal, increased and decreased] induced with Pentylentetrazole [PTZ] in Wistar male rats were investigated. Wistar male rats with similar response and sesitivity to PTZ and epileptiform seizures were randomly assigned to the five following: groups [n=8 for each group]. 1[st] exprimental group: Intramuscular injection of testosteron [5 mg/Kg BW] and after 2 hours intraperitoneal injection of PTZ [25mg/Kg BW/for max. 3 times]; 2[nd] exprimental group: treatment with testosteron [0.5 mg/Kg BW] for 10 days and injections of PTZ thereafter; control group for 1[st] and 2[nd] experimental rats where they received sesame oil and then PTZ in a protocol precisely similar to the 1[st] and 2[nd] groups; 3[rd] exprimental group: PTZ injections and recording of epileptiform convulsions before gonadectomy [as control] and repeat of PTZ injections after 10 days. The last protocol was performed in two groups: gonadectomized, without any testosteron injections, and gonadectomized but with one dose of testoteron. The results show that increase in serum testosteron level does not affect epileptiform convulsions, whereas the reduction of testosteron level increases the partial seizures [p<0.001] and duration of tonic-clonic seizures [p<0.05]. Results of this study show that testosteron has an anticonvulsant effect and this effect might be through neurosteroid metabolites, where these metabolites affect on GABA A receptor complex