Effect of Morus nigra aqueous extract treatment on the maternal-fetal outcome, oxidative stress status and lipid profile of streptozotocin-induced diabetic rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of uterine cervix constriction on Wistar rats

Purpose: To verify if uterine cerclage can induce craniosynostosis or any cranial deformity in new born Wistar rats. Methods: One pregnant female Wistar rat underwent laparotomy on day 18 of gestation and the uterus cervix was closed with a 3-0 nylon suture to avoid delivery, that occurs normally on the 21 day. The suture was released after 48 hours beyond the normal gestation period. The female rat delivered 11 pups. Six surviving rats from the delivery (group A - constrained group). Two rats were born from another mother and in the same age were used as control group (group B - 2 nonconstrained controls) were allowed to grow. They were sacrificed 1.2 years after their birth all the eight animals. Linear measurement, routine histology and computed tomography of the skull were performed at the time of their death to evaluate the cranial asymmetries by mesurements of the anatomical landmarks of the craniofacial skeleton of the rats on the two groups and compared then. Results: We did not observe statistically significant differences in any of the compared measurements (p>0.05) obtained through the morphologic and radiologic methods. Histologic examinations did not reveal any sign of premature fusion or suture imbrications. Critical decrease in longitudinal body size was noticed as the limbs too in all the animals of group A. Conclusion: Constriction of uterine cervix leads to fetus suffering, even death for a few animals, associated to small body size, but not to craniosynostosis.

Histochemical and morphological characteristics of the levator ani muscle in rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The influence of chronic stress imposed on pregnant rats on the induced bone loss in their adult offspring

Background and objective: Stress during pregnancy may alter offspring susceptibility to diseases during adulthood. In the present study, female Lewis rats were subjected to chronic stress during the gestational period, and the effect of this stress was evaluated histometrically on the progression of ligature-induced bone loss in their adult offspring.Material and methods: After confirming pregnancy, half of the pregnant rats were randomly designated as control animals (no stress regimen was imposed), and the other half was submitted to a chronic stress model (immobilization at cold temperature) between the 7th and the 18th gestational day. After birth, 12 male rats delivered by stressed mothers - Group 1 (G1) - and 12 male rats delivered by non-stressed mothers - Group 2 (G2) - were selected. When birthed rats reached 250 g of body weight, a silk ligature was placed around their maxillary right second molar in order to induce bone loss. The non-ligated left side served as a control. Sixty days later, these animals were sacrificed by anaesthetic overdose. After routine laboratorial processing, images of the histological sections were digitized and submitted for histometric measurement using two parameters: histological attachment loss and bone loss.Results: on the ligated side, G1 presented with greater histological attachment and bone loss than G2 (p < 0.05). on the non-ligated control side, neither of the groups presented with alterations in these parameters (p > 0.05).Conclusion: The chronic stress regimen imposed on pregnant rats produced a greater progression of ligature-induced bone loss in their adult offspring. (C) 0 2011 Elsevier Ltd. All rights reserved.

Involvement of L-glutamate and ATP in the neurotransmission of the sympathoexcitatory component of the chemoreflex in the commissural nucleus tractus solitarii of awake rats and in the working heart-brainstem preparation

Peripheral chemoreflex activation with potassium cyanide (KCN) in awake rats or in the working heart-brainstem preparation (WHBP) produces: (a) a sympathoexcitatory/pressor response; (b) bradycardia; and (c) an increase in the frequency of breathing. Our main aim was to evaluate neurotransmitters involved in mediating the sympathoexcitatory component of the chemoreflex within the nucleus tractus solitarii (NTS). In previous studies in conscious rats, the reflex bradycardia, but not the pressor response, was reduced by antagonism of either ionotropic glutamate or purinergic P2 receptors within the NTS. In the present study we evaluated a possible dual role of both P2 and NMDA receptors in the NTS for processing the sympathoexcitatory component (pressor response) of the chemoreflex in awake rats as well as in the WHBP. Simultaneous blockade of ionotropic glutamate receptors and P2 receptors by sequential microinjections of kynurenic acid (KYN, 2 nmol (50 nl)(-1)) and pyridoxalphosphate-6-azophenyl-2',4'-disulphonate (PPADS, 0.25 nmol (50 nl)(-1)) into the commissural NTS in awake rats produced a significant reduction in both the pressor (+38 +/- 3 versus +8 +/- 3 mmHg) and bradycardic responses (-172 +/- 18 versus -16 +/- 13 beats min(-1); n = 13), but no significant changes in the tachypnoea measured using plethysmography (270 +/- 30 versus 240 +/- 21 cycles min(-1), n = 7) following chemoreflex activation in awake rats. Control microinjections of saline produced no significant changes in these reflex responses. In WHBP, microinjection of KYN (2 nmol (20 nl)(-1)) and PPADS (1.6 nmol (20 nl)(-1)) into the commissural NTS attenuated significantly both the increase in thoracic sympathetic activity (+52 +/- 2% versus +17 +/- 1%) and the bradycardic response (-151 +/- 17 versus -21 +/- 3 beats min(-1)) but produced no significant changes in the increase of the frequency of phrenic nerve discharge (+0.24 +/- 0.02+0.20 +/- 0.02 Hz). The data indicate that combined microinjections of PPADS and KYN into the commissural NTS in both awake rats and the WHBP are required to produce a significant reduction in the sympathoexcitatory response (pressor response) to peripheral chemoreflex activation. We conclude that glutamatergic and purinergic mechanisms are part of the complex neurotransmission system of the sympathoexcitatory component of the chemoreflex at the level of the commissural NTS.

Antihypertensive effects of central ablations in spontaneously hypertensive rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nitric oxide modulates the cardiovascular effects elicited by acetylcholine in the NTS of awake rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chemosensory control by commissural nucleus of the solitary tract in rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of prenatal hydrocortisone acetate exposure on fertility and sexual behavior in male rats

The aim of the present study was to investigate the effects of hydrocortisone during the prenatal period and its later repercussions on the fertility and sexual behavior of male rats. Pregnant rats were treated (s.c.) with hydrocortisone acetate, at 1.5 mg/day on the 17th, 18th, and 19th days of gestation. Decreased body weight and no alteration in anogenital distance were observed in male offspring. Adulthood, presented reductions of body weight, plasma testosterone levels, and seminal-vesicle wet weight without secretion as well as no alteration in the wet weights of the testes, epididymis, and seminal vesicle with secretion in the treated group. Males exposed to hydrocortisone during the prenatal period were able to mate with normal females, which became pregnant but exhibited an increased number of post-implantation losses. In spite of this, these treated males exhibited decreased male sexual behavior and the appearance of female sexual behavior after these male rats were castrated and pretreated with exogenous estrogen. These results indicate that exposure to hydrocortisone in the later stages of pregnancy may have a long-term effect on the fertility and sexual behavior of mate rats, suggesting an incomplete masculinization and defeminization of the central nervous system. (C) 2003 Elsevier B.V. (USA). All rights reserved.

Effects of neonatal clomiphene citrate on fertility and sexual behavior in male rats

In order to investigate the participation of estrogen during the period of brain sexual differentiation, male rats were treated with clomiphene citrate in the neonatal phase. Fertility and sexual behavior were assessed during adult life. Sexual maturation, body weight, and wet weight of the testes were unchanged. Although the adult male rats treated with clomiphene in the neonatal phase presented a significant reduction in the frequency of mounts, 90% of these rats were able to mate with normal females, which became pregnant. However, these females exhibited a significantly increased number of pre- and post-implantation losses. When these adult male rats were castrated and received estrogen, 60% presented female sexual behavior (receptive behavior and acceptance of mount). Thus, treatment of pups with clomiphene immediately after birth has a long-term effect on the reproductive physiology and sexual behavior of male rats. (C) 2002 Elsevier B.V. All rights reserved.

Semen and reproductive parameters during some abstinence periods after cigarette smoke exposure in male rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Decreased production of TNF-alpha by lymph node cells indicates experimental autoimmune encephalomyelitis remission in Lewis rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Reproductive effects in male rats exposed to diuron

Diuron is a ureic herbicide considered to have very low toxicity. The present study evaluated several aspects of reproductive toxicity of diuron in adult male rats. Diuron was diluted in corn oil and administered by oral gavage to groups of 18-20 rats at doses of 0, 125 or 250 mg/kg per day for 30 days; the control group received only the corn oil vehicle. At the end of the treatment period, approximately half the animals from each group were assigned to one of two terminal assessment lines: (1) reproductive organ, liver and kidney weights; measurement of diuron concentrations in liver and kidney; plasma testosterone determinations; evaluation of daily sperm production per testis; sperm number and sperm transit time in the epididymis; or (2) sexual behavior assessment during cohabitation with a receptive female; fertility and pregnancy outcome after natural mating; testicular, epididymal, kidney and liver histopathology; sperm morphology. After 30 days of oral diuron treatment, there were no treatment-related changes in body weights, but dose-related diuron residues were detected in the liver of all treated rats and absolute and relative liver weights were increased in both groups. There were no statistically significant differences between the treated and control groups obtained in plasma testosterone concentrations, or in parameters of daily sperm production, sperm reserves in the epididymis, sperm morphology or measured components of male sexual behavior. on the other hand, the number of fetuses in the litters from diuron-treated rats was slightly smaller than litters from control rats. Therefore, although the results did not indicate that diuron exposure resulted in direct male reproductive toxicity in the rat, they suggest that additional studies should be undertaken to investigate the possible effects on fertility and reproductive performance. (c) 2006 Elsevier B.V. All rights reserved.

Sibutramine Effects on the Reproductive Performance of Pregnant Overweight and Non-Overweight rats

It is well established that sibutramine produces weight loss and is used frequently in women of childbearing age. However, the potential adverse consequences attributed to sibutramine use by women who may become pregnant is not known. It was thus of interest to determine the effects of sibutramine on the reproductive performance of pregnant rats. Overweight as well as non-overweight female Wistar rats were treated with sibutramine (6 mg/kg) orally, daily for 15 d and then mated with normal male rats. Pregnancy was confirmed and treatment continued with sibutramine until d 14 of pregnancy. on d 20 of pregnancy all rats were anesthetized for determination of various maternal and fetal parameters. There was a significant maternal weight reduction at the end of pregnancy in the non-overweight drug-treated group compared to the control (non-overweight, no drug). Sibutramine alone and overweight condition alone produced a significant increase in postimplantation loss and placental index. In the overweight with or without sibutramine groups a significant decrease in fetal weight was noted. Data suggest that sibutramine alone or the condition of excess weight in the absence of drugs produced impaired reproductive performance. However, treatment of overweight rats with sibutramine did not further exacerbate fetal loss compared to sibutramine alone or the effects noted with excess weight alone.

Morphometric-stereological and functional epididymal alterations and a decrease in fertility in rats treated with finasteride and after a 30-day post-treatment recovery period

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)