Neural cell transplantation effects on sciatic nerve regeneration after a standardized crush injury in the rat

The goal of the present study was to assess whether in vitro-differentiated N1E-115 cells supported by a collagen membrane would enhance rat sciatic nerve regeneration after a crush injury. To set up an appropriate experimental model for investigating the effects of neural cell transplantation, we have recently described the sequence of functional and morphologic changes occurring after a standardized sciatic nerve crush injury with a nonserrated clamp. Functional recovery was evaluated using the sciatic functional index, the static sciatic index, the extensor postural thrust, the withdrawal reflex latency, and ankle kinematics. In addition, histomorphometric analysis was carried out on regenerated nerve fibers by means of the 2D-disector method. Based on the results of the EPT and of some of the ankle locomotor kinematic parameters analyzed, the hypothesis that N1E-115 cells may enhance nerve regeneration is partially supported although histomorphometry disclosed no significant difference in nerve fiber regeneration between the different experimental groups. Therefore, results suggest that enrichment of equine type III collagen membrane with the N1E-115 cellular system in the rat sciatic nerve crush model may support recovery, at least in terms of motor function. The discrepancy between functional and morphological results also suggests that the combined use of functional and morphological analysis should be recommended for an overall assessment of recovery in nerve regeneration studies.

Use of hybrid chitosan membranes and N1E-115 cells for promoting nerve regeneration in an axonotmesis rat model

Many studies have been dedicated to the development of scaffolds for improving post-traumatic nerve regeneration. The goal of this study was to develop and test hybrid chitosan membranes to use in peripheral nerve reconstruction, either alone or enriched with N1E-115 neural cells. Hybrid chitosan membranes were tested in vitro, to assess their ability in supporting N1E-115 cell survival and differentiation, and in vivo to assess biocompatibility as well as to evaluate their effects on nerve fiber regeneration and functional recovery after a standardized rat sciatic nerve crush injury. Functional recovery was evaluated using the sciatic functional index (SFI), the static sciatic index (SSI), the extensor postural thrust (EPT), the withdrawal reflex latency (WRL) and ankle kinematics. Nerve fiber regeneration was assessed by quantitative stereological analysis and electron microscopy. All chitosan membranes showed good biocompatibility and proved to be a suitable substrate for plating the N1E-115 cellular system. By contrast, in vivo nerve regeneration assessment after crush injury showed that the freeze-dried chitosan type III, without N1E-115 cell addition, was the only type of membrane that significantly improved posttraumatic axonal regrowth and functional recovery. It can be thus suggested that local enwrapping with this type of chitosan membrane may represent an effective approach for the improvement of the clinical outcome in patients receiving peripheral nerve surgery.

Long-term functional and morphological assessment of a standardized rat sciatic nerve crush injury with a non-serrated clamp

We have recently described the sequence of functional and morphologic changes occurring after a standardized sciatic nerve crush injury. An 8-week post-injury time was used because this end point is the far most used. Unexpectedly, both functional and morphological data revealed that animals had still not recovered to normal pre-injury levels. Therefore, the present study was designed in order to prolong the observation up to 12 weeks. Functional recovery was evaluated using sciatic functional index (SFI), static sciatic index (SSI), extensor postural thrust (EPT), withdrawal reflex latency (WRL) and ankle kinematics. In addition, quantitative morphology was carried out on regenerated nerve fibers. A full functional recovery was predicted by SFI/SSI, EPT and WRL but not all ankle kinematics parameters. Moreover, only two morphological parameters (myelin thickness/axon diameter ratio and fiber/axon diameter ratio) returned to normal values. Data presented in this paper provide a baseline for selecting the adequate end-point and methods of recovery assessment for a rat sciatic nerve crush study and suggest that the combined use of functional and morphological analysis should be recommended in this experimental model.

Morphological and biochemical appraisal of the liver and renal effects of indinavir on rat pregnancy

Since indinavir is currently used in combination with other antiretroviral agents, there is a scarcity of studies in the literature on its single-drug perinatal safety. Thus, we decided to examine the gross maternal and fetal effects of indinavir administered alone during the entire period of rat pregnancy. Forty pregnant animals were assigned at random to four groups (C = control) treated with the drug vehicle (distilled water); the experimental groups were treated with indinavir as follows: E1 = 40 mg/kg; E2 = 120 mg/kg; E3 = 360 mg/kg from "zero" up to the 20th day of gestation. Drug or vehicle were administered daily by gavage. Each group consisted of ten animals. At term-pregnancy, the rats were deeply anesthetized and blood samples were collected for alanine aminotransferase (ALT) and aspartate aminotransferase (AST), creatinine and urea determinations. Fragments of maternal and fetal livers and kidneys were taken and routinely processed for histopathological study. Serum ALT activity in the E2 group was significantly higher (p < 0.01) than that of the other groups. The concentration of creatinine in blood was lower in the E2 and E3 groups than in group E1 (p < 0.01), whereas blood urea in group E3 was significantly lower than in the other groups (p < 0.01). Morphological (light microscopy) studies revealed that no significant effects of the drug could be detected regarding either maternal or fetal organs of the E1 and E2 groups. However, the maternal hepatocytes in the E3 group showed heterochromatic nuclei. In addition, there was some fatty infiltration, congested sinusoids and portal dilation. Maternal kidneys in the E2 and E3 groups revealed vascular dilation around the convoluted tubules. Regarding the biochemical determinations, the alterations observed were mild, without biological relevance, thus indicating that the treatment with indinavir during the entire gestation was essentially devoid of hepatic or renal effects which could result in altered metabolic parameters. It is concluded that indinavir was well tolerated in therapeutic and even in 9-fold higher doses. Notwithstanding, discrete morphological alterations occurred in the maternal compartment, but with no functional expression that could indicate deleterious effects on mothers and/or fetuses.

Effects of lopinavir-ritonavir combined therapy during the rat pregnancy. Morphological and biochemical aspects

OBJECTIVE

To evaluate the biochemical and morphological effects in rats subjected to three different dose associations of the protease inhibitors lopinavir and ritonavir administered throughout the entire period of pregnancy.

STUDY DESIGN

The animals were treated throughout pregnancy with daily oral doses of lopinavir+ritonavir starting at the day one of pregnancy, and were divided into four groups: E1, 13.3+3.3 mg/kg; E2, 39.9+9.9 mg/kg; E3, 119.7+29.9 mg/kg and C, control (drug vehicle, propyleneglycol). The animals were then sacrificed and maternal blood and fetal and maternal organ samples were taken for morphological and biochemical analysis.

RESULTS

No major changes were identified in the group treated with the lowest dose as compared with the control. In the group E2, we found hepatocytes with signs of atrophy, eosinophilic cytoplasm, picnotic nuclei and vasodilatation. The proximal convoluted tubules of maternal kidneys showed eosinophilic areas and hyperchromatic nuclei, as well as signs of vasodilation. In the group treated with the highest dose (group E3), in the maternal kidneys and livers, the morphological changes were similar to those found in E2, although more prominent. Regarding the fetal organs, the single abnormality observed was some liver vasodilation in the group E3 (highest dose). The treatment with lopinavir+ritonavir caused discrete, yet significant, alterations of aspartate aminotransferase activity, blood urea nitrogen and creatinine plasma levels.

CONCLUSIONS

Our results showed that the administration of a combination of lopinavir plus ritonavir to pregnant rats can cause morphological as well as functional changes in maternal and fetal liver and kidneys and, in higher than therapeutic doses, might be toxic to those animals.

Use of Hyperbaric Oxygenation in Small Bowel Preservation for Transplant

INTRODUCTION

The aim of this work was to study the effects of hyperbaric oxygenation as a preservation technique for small bowel transplantation.

METHODS

Twenty 2-month-old male Wistar rats weighting 250 g were divided into two groups: group A (n = 10) in which the small bowel was preserved for 12 hours, and group B (n = 10) in which the small bowel was preserved for 24 hours. After vascular and intraluminal perfusion, 3-cm segments were maintained in Ringer's solution at temperatures between 2 degrees C to 4 degrees C and in normobaric O2 conditions (groups A1, B1) or conditioned in an hyperbaric O2 metal chamber (100% oxygen at 5.5 absolute atmospheres) (groups A2, B2). After this preservation time, we studied intestinal tissue injury and morphometric analysis of the villi.

RESULTS

Mucosal injury was significantly greater among group A1 compared to group A2 animals. The grade of the lesions was greater among group B1 compared to group B2 animals. Group A1 showed no difference from Group B1. For lesion grade, the range was smaller in group A2 and group B2 animals. The villi height was significantly smaller in groups A1 and B1 compared to the other groups; whereas it was higher in group A2 as compared with B2.

CONCLUSION

Hyperbaric oxygenation may play a role as a preservation technique. Further research is necessary.

A Novel System for Organ and Tissues Preservation: The Refrigerating Hyperbaric Chamber

This study was designed to investigate the feasibility of building a simple and inexpensive device to preserve organs or tissues in hyperbaric and hypothermic conditions.

METHODS

The device was built on a 40-cm wide, 28-cm long, and 23-cm deep stainless steel chassis. The pressure vessel was built by a 7.8-cm bore stainless steel cylinder put inside another 12-cm cylinder welded together and closed by a steel plate on the top and bottom. The inferior plate was welded, and the superior one was fixed by manual clasp nut. The cooling system is made up of air compressor, condenser, expansion area, and cooling worm that is located between the cylinders. The temperature-controlling device is a computer processor contained in an integrated-circuit chip, with a on-off system to maintain the chamber temperature between 2 degrees to 4 degrees C. The compression of the chamber is performed by lateral coupling with the oxygen cylinder and is maintained at 5.5 absolute atmospheres and controlled by air pressure gauge. The maximal work pressure was evaluated by spreadsheet. Temperature or pressure changes were evaluated by 12- and 24-hour assays.

RESULTS

The maximal work pressure permitted was 6.5 absolute atmospheres. Thus, the container was free from danger. The temperature inside the chamber was kept between 2 degrees and 4 degrees C. The production costs of the prototype was US$1000.

DISCUSSION

The manufacture of the refrigerating hyperbaric chamber is viable, simple, and inexpensive.

Apoptosis and Nuclear Proliferation in Rat Small Bowel Submitted to Hypothermic Hyperbaric Oxygenation for Preservation

This study was conducted to assess apoptosis and nuclear proliferation in rat small bowel submitted to hypothermic hyperbaric oxygenation for preservation.

METHODS

Twenty two-month-old, male Wistar rats, weighing 250 g were divided into two groups: group I (n = 10), in which the small bowel was preserved for 12 hours, and group II (n = 10) in which the small bowel was preserved for 24 hours. After vascular and intraluminal perfusion, 3-cm segments were maintained in Ringer's solution at 2 degrees to 4 degrees C under normobaric conditions (groups Ia and IIa) or conditioned in a small hyperbaric metal chamber with 100% oxygen at 5.5 absolute atmospheres (groups Ib and IIb). After 12 or 24 hours, apoptotic and mitotic indices were evaluated by immunohistochemical methods.

RESULTS

The apoptotic index was significantly higher in small bowel segments in groups Ia and IIa compared with groups Ib and IIb. The mitotic index was significantly higher among group IIb.

CONCLUSION

Hypothermic hyperbaric oxygenation reduced intestinal epithelial apoptosis and increased nuclear proliferation during rat small bowel preservation.

A morphological and biochemical appraisal of the liver and renal effects of lamivudine on rat pregnancy

No data exist on the perinatal safety of lamivudine alone, as it is used in combination with other antiretroviral agents. Until now, only preliminary data on the lamivudine-zidovudine combination have been available, thus we decided to examine the gross maternal and fetal effects of lamivudine administered alone during the entire period of rat pregnancy. Forty pregnant animals were assigned at random to four groups (C1 = control; E1 = 5 mg/kg; E2 = 15 mg/kg; E3 = 45 mg/kg) from day 0 up to the 20th day of gestation. These doses were divided into two daily administrations by gavage. Controls (n = 10) received distilled water in the same schedule. At term-pregnancy, the rats were deeply anesthetized and blood samples were collected for alanine and aspartate aminotransferases, creatinine and urea determinations. Fragments of maternal and fetal livers and kidneys were taken and processed for histopathological study. In all groups blood transaminases were within the normal limits, as were the levels of creatinine and urea, thus indicating that treatment with lamivudine during the entire gestation was essentially devoid of liver or kidney effects which could result in altered metabolic parameters. Morphological (light microscopy) studies revealed that no significant effects of the drug could be detected regarding either maternal or fetal organs of the E1 and E2 groups. However, the maternal hepatocytes in the E3 group showed heterochromatic nuclei. In addition, there was some fatty infiltration, congested sinusoids and portal dilatation. Maternal kidneys in the E3 group revealed vascular dilation around the convoluted tubules. It is concluded that only doses of lamivudine used during the entire gestation in doses well above the usual human doses could be considered to be potentially hepatotoxic for the pregnant rat.

Safety of nelfinavir use during pregnancy. An experimental approach in rats

This experimental study aimed to evaluate the safety of nelfinavir when administered in normal up to high doses during the entire period of rat pregnancy. The renal and liver compartments of both mothers and fetuses were studied. For this purpose, three groups of pregnant rats were treated with nelfinavir (E1 = 40 mg/kg; E2 = 120 mg/kg; E3 = 360 mg/kg; no. = 10 in every group) from "zero" up to the 20th day of gestation. These doses were divided into two daily administrations by gavage. Controls (no. = 10) received distilled water in the same schedule. At term-pregnancy, the rats were deeply anesthesized and blood samples were collected for alanine and aspartate aminotransferases, creatinine and urea determinations. Fragments of maternal and fetal livers and kidneys were taken and processed for histopathological study. In all groups blood transaminases were within the normal limits, as were the levels of creatinine and urea, thus indicating that the treatment with nelfinavir during the entire gestation was essentially devoid of liver or kidney effects which could result in altered metabolic parameters. Morphological (light microscopy) studies revealed that no significant effects of the drug could be detected regarding either maternal or fetal organs of the E1 and E2 groups. However, the maternal hepatocytes in the E3 group showed heterochromatic nuclei. In addition, there was some fatty infiltration, congested sinusoids and portal dilatation. It is concluded that only doses of nelfinavir used during the entire gestation in doses well above the usual human doses could be considered to be potentially hepatotoxic for the pregnant rat.

Lysosomal evaluation of endometrioma capsule epithelium and endometrium of patients with or without endometriosis

OBJECTIVE

To evaluate the number of lysosomes in glandular epithelia of the endometrioma capsule and endometrium from patients with or without endometriosis using a histochemical method (acidic phosphate determination) under light microscopy.

METHOD

We studied 31 selected patients with similar clinical features, except for the occurrence of menorrhagia enhanced in patients with endometriosis. All patients were submitted to video laparoscopic procedures and endometrial biopsies through hysteroscopy during the secretory phase. After surgery, the patients were divided into two groups for hysteroscopic data: GI--without endometriosis (control, n = 16) and GII--with endometriosis (n = 15). In GII, the lysosomes of the endometrioma were also counted (GIIa).

RESULTS

The GI sample was comprised only of endometrial biopsies. We found that the number of lysosomes in the topic endometrial tissue of patients with endometriosis was significantly larger than the number in endometrioma. Also, there were more lysosomes in the endometrium of patients with endometriosis than in endometrioma-bearing patients.

CONCLUSION

Our data suggest that variations in the number of lysosomes may underlie the pathogenesis of endometriosis.

Effects of melatonin on the ovarian response to pinealectomy or continuous light in female rats: similarity with polycystic ovary syndrome

The current study was conducted to investigate the relationship between melatonin and chronic anovulation. Adult (3-4 months old) female Wistar rats were submitted to pinealectomy: group I: pinealectomized ovariectomized melatonin-treated (N = 10); group II: pinealectomized ovariectomized placebo-treated (N = 12); group III: pinealectomized light-treated placebo-treated (N = 10) or maintained under continuous light; group IV: maintained under continuous light, ovariectomized melatonin-treated (N = 22); group V: maintained under continuous light, ovariectomized placebo-treated (N = 10); group VI: maintained under continuous light placebo-treated (N = 10). In order to assess ovarian modifications, unilateral ovariectomy was performed during the fourth month in groups I, II, IV, V and the other ovary was removed after 8 months. Ovariectomy was performed in groups III and VI only after eight months. Melatonin (200 micro g/100 g body weight) dissolved in 0.02 ml absolute ethanol was injected intramuscularly daily during the last 4 months into groups I and IV. The other groups were treated with placebo (NaCl). The ovarian cysts were analyzed and their area, perimeter and maximum diameter, as well as the thickness of the ovarian capsule were measured. Daily colpocytological smears were performed throughout the study. Persistent estrous condition and ovarian cysts were observed in all groups. In pinealectomized rats the ovarian and vaginal alterations disappeared at the end of the study and in rats maintained under continuous light the vaginal and ovarian polycystic aspect was reversed only in those treated with melatonin. We conclude that melatonin may act on the ovarian response reverting chronic anovulation induced by pinealectomy or continuous light.

Evaluation of Langerhans' cells in human papillomavirus-associated squamous intraepithelial lesions of the uterine cervix

Current research has been evaluating morphological modifications and density of Langerhans' cells in women with histopathological HPV lesions of the uterine cervix. Fourteen women with subclinical HPV infections underwent clinical, colpocytological colposcopy examinations, and paired biopsies of the uterine cervix. Histopathological, HPV hybrid capture and S-100 immunohistochemical examinations were performed in biopsy specimens. Groupings of viral lesions and normal tissue were analyzed by the Wilcoxon rank-sum test. Langerhans' cells in the specimens were frequently located in the intermediate and basal layers of the epithelium. A significant reduction of cytoplasmic profiles occurred in viral lesions (144.08 profiles/mm2) when compared to normal tissue (256.27 profiles/mm2) of the epithelium. An inverse modulation occurred in the cytoplasmatic profiles/nuclei ratio with 2.80 in viral lesions and 4.89 in normal tissue of the stroma. A local immunodeficiency based on cytoplasmic changes of Langerhans' cells has been postulated as a mechanism by which HPV could be involved in the genesis of neoplasia.

Effect of chronic ritonavir administration on pregnant rats and their fetuses

In view of the very important role played by ritonavir in the prevention of maternal-fetal HIV-vertical transmission, the aim of this experimental study was to evaluate its possible effects on several important obstetric parameters. Ritonavir was administered daily to three groups of pregnant rats (E1 = 20 mg/kg; E2 = 60 mg/kg; E3 = 180 mg/kg; n = 10 in every group) from 'zero' up to the 20th day of pregnancy. Controls (n = 10) were injected with the drug vehicle (propyleneglycol) in the same schedule. We evaluated the effects on fetal and maternal weight gain, placental weight, number of implantations and resorptions, malformations, fertility rate, and maternal and fetal death rates. Body weight gain of the E3 group was significantly lower than that of the other groups, most likely due to a toxic effect of the highest dose of ritonavir. Ritonavir did not affect the number of implantations. Group E3 had five resorptions and some reduction in fertility. The mortality rate was significantly affected by ritonavir (2/10 maternal deaths in E2 and 4/10 in E3). On the other hand, no alterations were observed in the fetuses, a finding which could be due at least in part to the protective action of placental P-glycoprotein.

Long-term acetaminophen (paracetamol) treatment causes liver and kidney ultra-structural changes during rat pregnancy

Acetaminophen (paracetamol) is an analgesic-antipyretic drug virtually devoid of typical anti-inflammatory activity and hence free of some of the side-effects of aspirin and related agents (e.g. gastric erosion and bleeding complications). The worldwide use of paracetamol as a household analgesic, including during pregnancy, prompted us to investigate its potentially deleterious effects in that setting. Pregnant rats were treated with paracetamol (150, 500 or 1,500 mg/kg, once a day by gavage) from the first day up to term pregnancy. In the group treated with the lowest doses, no histological changes were noticed in maternal and fetal livers or kidneys when examined under light or electron microscopy. With the higher doses, however, various dose-dependent effects of paracetamol were observed, namely necrotic areas of the liver seen with light microscope and further confirmed by electron microscopy. The kidneys revealed degeneration and necrotic foci under light microscopy with ultrastructural derangements. Electronmicrographs of the liver revealed hepatocytes bearing translucent bodies as a consequence of a dilated smooth endoplasmic reticulum. There were signs of necrosis both in the hepatocytes (lysis of mitochondria and presence of lipid droplets) and renal tissue (mitochondrial cytolysis in convoluted tubules). Our data point out the fact that both maternal and fetal tissues can be adversely affected by paracetamol.

Pinealectomy changes rat ovarian interstitial cell morphology and decreases progesterone receptor expression

The aim of this study was to evaluate the rat ovarian morphological and function changes after pinealectomy (px). Two months after px, young female Wistar rats were sacrificed and the right ovaries were analysed morphologically and the left ovaries were used for steroid receptor binding experiments. Blood was collected and steroid hormone and melatonin levels were measured using radioimmunoassay kits. Results revealed that in the px group the rat ovaries had an increase in the number of atretic follicles and interstitial cells. These cells showed hyperactivity features on transmission electron microscopy and morphometric analysis (p < 0.05 compared with control and sham groups). Px-group serum showed an increase in estradiol (p < 0.05) and a decrease in progesterone levels (p < 0.05) compared with other groups. Moreover, progesterone receptor expression was lower than control and sham groups (p < 0.05). We postulate that pinealectomy leads to many morphological alterations of rat ovaries that are associated with functional changes in steroidogenesis and a decrease in progesterone receptor expression.

Liver and kidney ultrastructural changes caused by acetylsalicylic acid treatment during pregnancy in rats

The worldwide use of acetylsalicylic acid (ASA) as an analgesic-antipyretic drug, including during pregnancy, prompted us to investigate its potentially deleterious effects in that condition. Pregnant rats were treated with ASA (1, 10 or 100 mg/kg once a day) from the first day up to term pregnancy. No histological changes were noticed in maternal and fetal livers or kidneys when examined under light microscopy, but some definite dose-dependent effects of ASA were observed on electron microscopy examination. In livers and kidneys of pregnant rats treated with the highest doses of ASA we observed cytoplasmic derangement, mitochondrial cristolysis and abnormally shaped rough endoplasmic reticulum. Similarly, in foetal livers and kidneys from this group we observed degenerative cytoplasmic vacuoles and ballooned mitochondria with cristae derangement and myelin figures. Our data point out the fact that both maternal and foetal tissues can be importantly affected by ASA at the ultrastructural level, without overt signs of toxicity.

Analysis of collagen in parametrium and vaginal apex of women with and without uterine prolapse

Our objective was to compare the amount of collagen in parametrium and vaginal apex between women with uterine prolapse at pre- and postmenopause, and in women without prolapse. The study included 22 premenopausal women without prolapse (group A), 10 premenopausal women with prolapse (group B), and 23 postmenopausal women with prolapse (group C) (total 55). Patients in group A underwent abdominal hysterectomy for uterine leiomyoma, and patients in groups B and C underwent vaginal hysterectomy. During the surgical procedure we obtained biopsies from the lateral parametrium and vaginal apex. The tissue was stained for histological analysis with picrosirius. We observed a lower amount of collagen in the parametrium of women with uterine prolapse, both in menacme and in postmenopause, than in the parametrium of women without prolapse. We observed no statistically significant difference in vaginal apex between the groups.

Gangliosides in rat femoral injury: early effect on intimal hyperplasia

Previous studies demonstrated that some immunosuppressive agents inhibit arterial intimal hyperplasia. Our previous studies demonstrated that gangliosides (Gang) have an immunosuppressive effect on as well as an anti-inflammatory role in the wound-healing process. Therefore, we decided to examine the effect of Gang on intimal hyperplasia. Twenty Wistar isogenic rats received a transverse division of the anterior wall of the femoral artery, followed by suturing using mononylon 10-0 under surgical microscopy and were then divided into two groups: Gang group, 3 mg/kg per day of Gang, and control group, vehicle, intramuscularly from surgery to death (1 and 3 weeks, respectively). Concentric intimal hyperplasia was observed in arteries stained by hematoxylin-eosin in control and Gang groups. However, the media layer did not demonstrate any major alterations. After 3 weeks, the Gang group showed more intimal hyperplasia than the control group. Therefore, because intimal hyperplasia worsened in the presence of Gang after 3 weeks, further studies will be necessary to clarify its role in intimal proliferation.

Ultrastructural aspects of the postmenopausal endometrium after oral or transdermal estrogen administration

In this report we examined the ultrastructural features of the postmenopausal endometrial cells of women treated with different doses of conjugated equine estrogen (CEE), or transdermal 17beta-estradiol. Eight women with uterine prolapse and at least 5 years of menopause were randomly divided into four groups and treated as follows: (I) no hormonal treatment; (II) 0.625mg/day of CEE orally; (III) 1.25mg/day of CEE orally; (IV) 50microg/day of 17beta-estradiol transdermally. Hormones were administered for 28 days followed by vaginal hysterectomy. Fragments of the endometrium were prepared for transmission electron microscopic analysis. We observed that the postmenopausal endometrium of the untreated group was atrophic with lined superficial epithelial cuboidal cells. The presence of gland and stroma cells with clear cytoplasm containing few organelles and heterochromatin nuclei were also observed. On the contrary, the endometrium of the group that received 0.625mg/day of CEE showed signs of proliferative cells such as the presence of numerous organelles in the cytoplasm and euchromatic nuclei. All of the proliferative effects on the endometrium were more pronounced in the groups that received 1.25mg/day of CEE and 50microg/day of transdermal 17beta-estradiol. We concluded that the ultrastructural proliferative changes of the postmenopausal endometrium induced by 1.25mg/day of CEE were similar to 50microg/day of transdermal 17beta-estradiol.

Morphologic and morphometric study of the breast parenchyma of rats in persistent estrus treated with tamoxifen and conjugated estrogens

PURPOSE

To evaluate the morphological and morphometric alterations produced by tamoxifen and conjugated estrogens in the mammary epithelium of rats in persistent estrus.

METHODS

33 adult female rats with persistent estrus induced by 1.25 mg testosterone propionate were divided at random into three groups: group I (n=12), receiving only water and used as a control; group II (n=10), treated with 500 microg tamoxifen daily; group III (n= 11), treated with 30 microg conjugated estrogens daily. The first abdominal-inguinal pair of breasts was extirpated and processed for morphological and morphometric study. Data were analyzed statistically by the Kruskal-Wallis rank analysis of variance (p<0.05).

RESULTS

The morphological study revealed signs of epithelial atrophy and the morphometric study showed a significant reduction in mean number of ducts and alveoli in groups II (10.1 and 1.9, respectively) and III (11.1 and 3.5, respectively) compared to the control group 1 (25.0 and 6.6, respectively). There was no significant difference between groups II and III.

CONCLUSIONS

The present results indicate that, at the doses and during the time of treatment used, both tamoxifen and conjugated estrogens induced atrophy of the mammary epithelium of rats in persistent estrus.