Effects of androgenic modulation on the morphophysiology of the adrenal cortex of male gerbils.

The study aimed to investigate the repercussions of androgen modulation on the adrenal cortex of male gerbils, focusing on the morphophysiology, proliferation, and cell death, as well as the expression of hormone receptors and steroidogenic enzymes. Mongolian gerbils (Meriones unguiculatus) were divided into three experimental groups: Control (C), Testosterone (T), animals received injections of testosterone cypionate and Castrated (Ct), animals underwent orchiectomy. The results showed that castration increased the zona fasciculata and promoted cell hypertrophy in all zones. Testosterone supplementation increased cell proliferation and cell death. Androgen modulation promoted an increase in AR, Erα, and ERß. Castration promoted an increase in the CYP19, while decreasing 17ßHSD enzymes. Testosterone supplementation, on the other hand, reduced CYP17 and increased CYP19 and 3ßHSD enzymes. By analyzing the effects of androgen supplementation and deprivation, it can be concluded that testosterone is responsible for tissue remodeling in the cortex, regulating the rate of cell proliferation and death, as well as cell hypertrophy. Testosterone also modulate steroid hormone receptors and steroidogenic enzymes, consequently affecting the regulation, hormone synthesis and homeostasis of this endocrine gland.

Prostatic morphological changes throughout life: Cytochemistry as a tool to reveal tissue aging markers.

The prostate undergoes normal or pathological morphological changes throughout life. An understanding of these changes is fundamental for the comprehension of aging-related pathological processes such as benign prostatic hyperplasia (BPH) and cancer. In the present study, we show some of these morphological changes, as well as histochemical techniques like Weigert's resorcin-fuchsin method, Picrosirius Red, and Gömöri's reticulin for use as tools in the study of prostate tissue under light microscopy. For this purpose, prostates of the Mongolian gerbil (n = 9), an experimental model that develops BPH spontaneously, were analyzed at three life stages: young (1 month old), adult (3 months old), and old (15 months old). The results showed that fibrillar components such as collagen, and reticular and elastic fibers, change throughout life. In young animals, the prostate has cuboidal epithelium surrounded by thin layers of smooth muscle, continuous collagen fibers, winding reticular fibers, and sporadic elastic fibers. With adulthood, the epithelium becomes columnar, encircled by compacted muscle cells among slender collagen fibers, elongated reticular fibers, and linear elastic fibers. In aging individuals, the prostate's epithelium stratifies, surrounded by thick muscle layers among dense collagen fibers, disordered reticular fibers, and elastic fibers in different planes. We also identified a few accumulations of lipid droplets and lipofuscin granules in adult animals and high accumulation in old animals evidenced by Oil red O and Gömöri-Halmi techniques, respectively. The histochemical techniques presented here have been demonstrated to be useful and accessible tools in prostate studies. RESEARCH HIGHLIGHTS: Cytochemical techniques to study prostate morphology. The prostate changes with age.

The impacts of exposure to bisphenol A in the adult female prostate Meriones unguiculatus.

The female prostate is associated with the urogenital system and presents homology in morphological terms with the male prostate. Due to its responsiveness to endogenous hormones, this gland is under a constant risk of developing prostatic pathologies and neoplasia when exposed to certain exogenous compounds. Bisphenol A (BPA) is an endocrine disruptor found in different plastic and resin products. Studies have emphasized the effects of perinatal exposure to this compound on different hormone-responsive organs. However, there have been few studies highlighting the influence on female prostate morphology of perinatal exposure to BPA. The objective of this study was to describe the histopathological alterations caused by perinatal exposure to BPA (50 µg/kg) and 17-ß estradiol (E2) (35 µg/kg) in the prostate of adult female gerbils. The results showed that E2 and BPA induced proliferative lesions in the female prostate and acted along similar pathways by modulating steroid receptors in the epithelium. BPA was also found to be a pro-inflammatory and pro-angiogenic agent. The impacts of both agents were marked in the prostatic stroma. An increase in the thickness of the smooth muscle layer and a decrease in AR expression were observed, but no alterations in the expression of ERα and ERß, leading to estrogenic sensitivity of the prostate. However, a peculiar response of the female prostate was to diminish the collagen frequency under BPA exposure correlated to smooth muscle layer. These data therefore indicate the development of features related to estrogenic and non-estrogenic tissue repercussions by BPA perinatally exposure in gerbil female prostate.

Female Prostate Development: Morphological Analysis of the Budding Dynamic.

The presence of the prostate in female mammals has long been known. However, pieces of information related to its development are still lacking. The aim of this study was to explore the budding dynamic during the initial prostate development in female gerbils. Pregnant females were timed, the fetuses were euthanized, and the urogenital sinus was dissected out between the embryonic days 20 and 24 (E20-E24 groups). Newborn pups (1-day-old; P1 group) underwent the same procedures. The female prostate development was based on epithelial buds which arose far from the paraurethral mesenchyme (PAM). The epithelial buds reached the PAM at prenatal day 24, crossing a small gap in the smooth muscle layer between the periurethral mesenchyme (PEM) and the PAM. Steroid nuclear receptors such as the androgen receptor and estrogen receptor alpha were localized in the PEM through the urethral wall, although some epithelial labeling was also present in the urogenital sinus epithelium (UGE). P63-positive cells were found only in the UGE, becoming restricted to the basal compartment after the 23rd prenatal day. The results showed that the gerbil female prostate exhibits a distinct budding pattern as compared to the male prostate development.

Prolactin promotes a partial recovery from the atrophy of both male and female gerbil prostates caused by castration.

BACKGROUND: The male and female prostates are controlled by steroid hormones, suffering important morphological and physiological changes after castration. Prolactin is involved in the regulation of the male prostate, having already been identified in the tissue, acting through its receptor PRLR. In the Mongolian gerbil, in addition to the male prostate, the female prostate is also well developed and active in its secretion processes. The aim of the present study was to evaluate the effects of exposure to exogenous prolactin in the prostate of both intact and castrated male and female gerbils in order to establish if prolactin administration can sustain prostate cell activity in conditions of sexual hormone deprivation. METHODS: The morphological analyses were performed by biometric analysis, lesion histological analysis and morphometric-stereological aspects. In addition, immune-cytochemical tests were performed for prolactin and its receptor, as well as for the receptors of androgen and oestrogen and serum prolactin dosage. All data were submitted to ANOVA or Kruskal-Wallis tests for comparison between groups. P < 0.05 was considered to be statistically significant. RESULTS: The results showed a strong influence of prolactin on the morphology of the prostate, with the development of important epithelial alterations, after only 3 days of administration, and an expressive epithelial cell discard process after 30 days of administration. Prolactin acts in synergy with testosterone in males and mainly with oestrogens in females, establishing different steroid hormonal receptor immunoreactivity according to sex. It was also demonstrated that prolactin can assist in the recovery from some atrophic effects caused in the gland after castration, without causing additional tissue damage. CONCLUSIONS: The prolactin and its receptor are involved in the maintenance of the homeostasis of male and female gerbils, and also cause distinct histological alterations after exogenous exposure for 3 and 30 days. The effects of prolactin are related to its joint action on androgens and oestrogens and it can also assist in the recovery from the atrophic effects of castration.

Nematicidal activity of a hydroalcoholic extract of the edible mushroom Neolentinus ponderosus on L3 larvae of Haemonchus contortus.

OBJECTIVE: In the present study, the in vitro and in vivo effect of the hydroalcoholic extract of Neolentinus ponderosus (EHNP) on L3 larvae of Haemonchus contortus was evaluated. MATERIAL AND METHODS: The N. ponderosus fungus was cultivated in potato dextrose liquid medium for 7 days at 120 rpm and 25 °C. Subsequently, the EHNP was obtained; in vitro bioassays were performed in 96-well plates. Furthermore, an in vitro confrontation with different concentrations of EHNP was carried out at 72 h against L3 larvae of H. contortus. The controls used were distilled water and ivermectin at 5 mg/mL. Subsequently, the in vivo activity of EHNP was evaluated using the gerbil against H. contortus L3 larvae as an experimental model. The experimental design consisted of four groups with: (1) distilled water, (2) fenbendazole at 20 mg/kg of body weight, (3) EHNP at a dose of 81 µg/mL, and (4) EHNP at a dose of 40 µg/mL. RESULTS: In vitro study showed 97% mortality of the parasite H. contortus at a concentration of 3.4 mg/mL and a lethal concentration (LC90) of 2 mg/mL EHNP. In the in vivo assessment the highest mortality was (49%) at 72 h at a concentration of 81 µg/mL bw. CONCLUSION: The result of the present study shows that EHNP has nematicidal activity in vitro and in vivo tests (close to 97% and 50%, respectively), the fungus N. ponderosus should be considered in future tests to elucidate the secondary metabolites through spectroscopic studies.

The Influence of Pregnancy on Female Prostate Morphophysiology in Gerbils (Meriones unguiculatus).

Morphophysiological changes of the female prostate during pregnancy are still little known. Considering that this gland is highly influenced by steroid hormones, the aim of this study was to evaluate the impact of the pregnancy on female prostate morphophysiology in gerbils. Pregnant females were timed, and the prostates were analyzed at pregnancy days 6 (P6), 12 (P12), 18 (P18), and 24 (P24). Virgin females were used as the control group (C). We observed a profound change in the hormonal profile during gestation, which was marked by a high oscillation of the progesterone (P4) hormone. P4 serum levels increased, peaking at the middle of gestation, and decreased to the end of the pregnancy. The morphology of the gland in pregnant females also changed, being marked by an increase of acini lumen, and a decrease in stroma. Indeed, the acinar changes during pregnancy were followed by a significant reduction of the epithelial height, besides a change of the smooth muscle cells' morphology that became more relaxed. The number of progesterone receptor (PR) and androgen receptor (AR)-positives cells decreased with the increase of progesterone serum levels, showing an inverse relationship. Finally, we observed a reduction of epithelial proliferation and a significant increase of gland PAS-positive secretion at the end of pregnancy. Altogether, these results showed, for the first time, that the female prostate morphophysioloy is profoundly influenced by the gestational period, suggesting that the fluctuation of the P4 serum levels is the main factor influencing the gland during this period.

Telocytes are associated with tissue remodeling and angiogenesis during the postlactational involution of the mammary gland in gerbils.

The postlactational involution of the mammary gland is a complex process. It involves the collapse of the alveoli and the remodeling of the extracellular matrix, which in turn implies a complex set of interrelations between the epithelial, stromal, and extracellular matrix elements. The telocytes, a new type of CD34-positive stromal cell that differs from fibroblasts in morphological terms and gene expression, were detected in the stroma of several tissues, including the mammary gland; however, their function remains elusive. The present study employed three-dimensional reconstructions and immunohistochemical, ultrastructural, and immunofluorescence techniques in histological sections of the mammary gland of the Mongolian gerbil during lactation and postlactational involution to evaluate the presence of telocytes and to investigate a possible function for these cells. By means of immunofluorescence assays for CD34 and c-kit, major markers of telocytes, and also through morphological and ultrastructural evidences, telocytes were observed to surround the mammary ducts and collapsing alveoli. It was also found that these cells are associated with matrix metalloproteinase 9, which indicates that telocytes can play a role in extracellular matrix digestion, as well as vascular endothelial growth factor, a factor that promotes angiogenesis. Together, these data indicate that telocytes are a distinct cell type in the mammary gland and, for the first time, show that these cells possibly play a role in tissue remodeling and angiogenesis during the postlactional involution of the mammary gland.

Postnatal exposure to finasteride causes different effects on the prostate of male and female gerbils.

The development and maintenance of prostate function depend on a fine balance between oestrogen and androgen levels. Finasteride inhibits 5α-reductase, which is responsible for the conversion of testosterone into its most active form, dihydrotestosterone. Enzymes that metabolize these hormones have a highly relevant role in both the normal prostate metabolism and in the occurrence of pathological conditions. There are few studies on the impact of finasteride on male prostate development and fewer studies on the female prostate and possible intersexual differences. Therefore, we treated male and female gerbils from 7 to 14 days in postnatal life with a high dose of finasteride (500 µg/kg/day); the prostate complexes were then removed and submitted to immunohistochemistry, immunofluorescence and three-dimensional reconstruction. In addition, hormonal serum dosages were administered. Treatment with finasteride resulted in an increased thickness of the periductal smooth musculature in the prostate of both male and female gerbils, such as well as a reduction in the thickness of developing prostate alveoli in both sexes. In addition, intersexual differences were observed as increased epithelial proliferation and decreases in the number of developing alveoli in females. Together, the data indicate that postnatal exposure to finasteride causes greater changes in the female gerbil prostate than in the male.

Impact of perinatal bisphenol A and 17ß estradiol exposure: Comparing hormone receptor response.

Hormonal regulation controls mammary gland (MG) development. Therefore some hormone-related factors can disrupt the early phases of MGs development, making the gland more susceptible to long term modifications in its response to circulating hormones. Endocrine disruptors, such as bisphenol A (BPA), are able to cause alterations in hormone receptor expression, leading to changes in the cell proliferation index, which may expose the tissue to neoplastic alterations. Thus, we evaluated the variations in hormone receptor expression in the MG of 6-month old Mongolian gerbils exposed to BPA and 17ß estradiol during the perinatal period. Receptors for estrogen alpha (ERα), beta (ERß), progesterone (PGR), prolactin (PRL-R), and co-localization of connexin 43 (Cx43) and ERα in gerbils were analyzed, and serum concentrations of estradiol and progesterone were assessed. No alterations in body, liver, and ovary-uterus complex weights were observed. However, there was an increase in epithelial ERα expression in the 17ß estradiol (E2) group and in PGR in the BPA group. Although immunohistochemistry did not show alterations in ERß expression, western blotting revealed a decrease in this protein in the BPA group. PRL-R was more present in epithelial cells in the vehicle control (VC), E2, and BPA groups in comparison to the intact control group. Cx43 was more frequent in E2 and BPA groups, suggesting a protective response from the gland against possible malignancy. Serum concentration of estradiol reduced in VC, E2, and BPA groups, confirming that alterations also impacts steroid levels. Consequently, perinatal exposure to BPA and the reference endogenous estrogen, 17ß estradiol, are able to increase the tendency of endocrine disruption in MG in a long term manner, since repercussions are observed even 6 months after exposure.

Low-dose in utero exposure to finasteride promotes developmental changes in both male and female gerbil prostates.

The prostate is an accessory reproductive gland that is sensitive to the action of exogenous compounds known as endocrine disrupters that alter normal hormonal function. Finasteride is a widely used chemical that acts to inhibit the conversion of testosterone in its most active form, dihydrotestosterone. It is known that intrauterine exposure to finasteride causes changes in the male prostate even at low dosages; however, it is not known whether these dosages are capable of causing changes in the female prostate, which is present in a large number of mammalian species, including humans. In the present study, histochemistry, immunohistochemistry, immunofluorescence, serological dosages, and three-dimensional reconstruction techniques were employed to evaluate the effects of intrauterine exposure to a low dose of finasteride (100 µg.BW/d) on postnatal prostate development in male and female Mongolian gerbils. The results indicate that the gerbil female prostate also undergoes alterations following intrauterine exposure to finasteride, exhibiting a thickening of periductal smooth muscle and increased stromal proliferation. There are also intersex differences in the impact of exposure on the expression of the androgen receptor, which was increased in males, and of the estrogen-α receptor, which was decreased in the male prostate but unchanged in females. Altogether, this study indicates there are sex differences in the effects of finasteride exposure even at low dosages.

Diazepam Reduces Escape and Increases Closed-Arms Exploration in Gerbils After 5 min in the Elevated Plus-Maze.

Despite the wide implementation of the elevated plus-maze (EPM) test to assess anxiety-related behaviors in rodents, the interpretation of these measures in gerbils has received limited attention. Here, male gerbils were treated with vehicle or diazepam, followed by a 20-min EPM session. EPM data were subjected to minute-by-minute, 5-min bins and factor analyses. During the first 5-min, gerbils avoided the closed arms in favor of the open arms and diazepam increased open-arms entries; furthermore, a single factor (escape behavior) explained all the analyzed measures. Only after 5-min, gerbils reduced open-arms exploration and three independent factors emerged for each subsequent 5-min bin. These findings suggest that EPM data from gerbils should be analyzed in at least two 5-min bins. Measures from the standard 5-min session seem to be related to an escape response from the EPM through the open arms. Once habituated, measures from the second 5-min bin seem to be related to a conflictive situation: keep trying to escape unsuccessfully (due to open-arms height) or seek protection in the closed arms (unsafe places). Diazepam seems to reduce this conflict by mitigating the escape response (Factor 1 - Anxiety) and increasing closed-arms approach (Factor 2) and risk assessment (Factor 3). Unlike mice and rats, a decrease in open-arms exploration and an increase in risk assessment could be interpreted as an anxiolytic-like effect in gerbils.

Effect of probiotic Saccharomyces boulardii in experimental giardiasis.

The aim of the study was to assess the efficacy of Saccharomyces boulardii in experimental treatment of giardiasis and its impact on intestinal integrity and some functions of gerbils infected with Giardia lamblia. 28 gerbils (Meriones unguiculatus), aged 4-6 weeks, were divided into four groups: untreated and uninfected control (CT); infected with G. lamblia (IGL); treated with S. boulardii (SB); and infected with G. lamblia and treated with S. boulardii (ITSB). The SB and ITSB groups received S. boulardii 15 days prior to being infected with G. lamblia. The treatment continued until completion of the experiment (22nd day). The IGL and ITSB groups were gavage-inoculated with G. lamblia ensuring one-week infection. 4 h before euthanasia, all animals were gavaged with a solution containing diethylenetriamine-pentaacetic acid (DTPA) marked with technetium-99mTc DTPA to determine intestinal permeability. The small intestine was removed for histopathological, morphometric analysis and count of trophozoites adhered to the mucosa. The selected probiotic caused an approximate reduction of 70% of parasite load, which was determined by attached trophozoites (P<0.01) and immune-marked trophozoites (P<0.05). Treatment with S. boulardii (SB and ITSB groups) also increased the height of the intestinal villi and crypt depth compared to the CT and IGL groups (P<0.05). The area of mucus production and the number of goblet cells of the SB and ITSB groups were higher compared to the CT and IGL groups (P<0.01). The animals treated with S. boulardii also exhibited a significant increase of intraepithelial lymphocytes counts (P<0.01). There was no difference in the intestinal permeability between the groups studied. The efficacy of S. boulardii in reducing damages caused by Giardia was demonstrated, with an approximate reduction of 70% of the parasite load, suggesting its use as a coadjuvant in giardiasis treatment.

Caudectomia devido à avulsão de cauda em Gerbilo (Meriones unguiculatus): Relato de Caso / Caudectomy due to avulsion of tail in Gerbil (Meriones unguiculatus): Case Report / Caudectomía debido a la avulsión de cola en Gerbil (Meriones unguiculatus): Relato de Caso

O presente trabalho relata o caso de um gerbilo com necrose da extremidade de cauda em que foi realizada caudectomia como tratamento de escolha. O procedimento foi realizado sem intercorrências,com o animal sob anestesia volátil complementada com bloqueio local. A recuperação do animal foi satisfatória, apresentando rápida cicatrização da ferida cirúrgica.(AU)

This paper reports the case of a gerbil with necrosis of the tail end that washeld caudectomia como treatment of choice. The procedure was performed uneventfully, with the animal under volatile anesthesia supplemented with local anesthesia. The animal's recovery was satisfactory, with rapid healing of the surgical wound.(AU)

Se comunica el caso de un jerbo con necrosis del extremo de la cola, que se celebró caudectomia como tratamiento de elección. El procedimiento se realizó sin incidentes, con el animal bajo anestesia volátiles suplementado con anestesia local. La recuperación del animal fue satisfactoria, con una rápida cicatrización de la herida.(AU)

Caudectomia devido à avulsão de cauda em Gerbilo (Meriones unguiculatus): Relato de Caso / Caudectomy due to avulsion of tail in Gerbil (Meriones unguiculatus): Case Report / Caudectomía debido a la avulsión de cola en Gerbil (Meriones unguiculatus): Relato de Caso

O presente trabalho relata o caso de um gerbilo com necrose da extremidade de cauda em que foi realizada caudectomia como tratamento de escolha. O procedimento foi realizado sem intercorrências,com o animal sob anestesia volátil complementada com bloqueio local. A recuperação do animal foi satisfatória, apresentando rápida cicatrização da ferida cirúrgica.

This paper reports the case of a gerbil with necrosis of the tail end that washeld caudectomia como treatment of choice. The procedure was performed uneventfully, with the animal under volatile anesthesia supplemented with local anesthesia. The animal's recovery was satisfactory, with rapid healing of the surgical wound.

Se comunica el caso de un jerbo con necrosis del extremo de la cola, que se celebró caudectomia como tratamiento de elección. El procedimiento se realizó sin incidentes, con el animal bajo anestesia volátiles suplementado con anestesia local. La recuperación del animal fue satisfactoria, con una rápida cicatrización de la herida.

Prepubertal chrysin exposure upregulates either AR in male ventral prostate or AR and ERα in Skene's paraurethral gland of pubertal and adult gerbils.

Chrysin is a plant-derived polyphenol that has the potential to increase endogenous testosterone levels both by inhibiting the aromatase enzyme and by stimulating testicular steroidogenesis. The effects of chrysin on the prostate are unknown, especially during its development and functional maturation. Thus, the aim of this study was to evaluate the effects of chrysin prepubertal exposure on the male and female prostates of both pubertal and adult gerbils. To evaluate the possible androgenic responses of chrysin, gerbils were also exposed to testosterone. Male and female gerbils were exposed to chrysin or to testosterone cypionate from postnatal day 15 to 42. Male and female gerbils were euthanized at either 43days or 90days age. The prostates were collected for biometrical, morphological and immunohistochemical analysis. The results showed that prepubertal exposure to chrysin had differential effects on the prostate of both pubertal and adult animals. The prostates of male and female pubertal gerbils showed no histological alterations, although there was increased frequency of androgen receptor (AR) in males and females, and estrogen receptor alpha (ERα) in females. Adult males and females presented developed prostate glands, with higher cell proliferative rate. In addition, AR and ERα frequency remained high in the prostate of adult animals. These results demonstrated that prepubertal exposure to chrysin disrupts steroid receptors regulation in the prostate, potentiating the response of this gland to the biological effects of endogenous steroids. In this context, excessive consumption of phytoestrogens during the critical stages of development should be considered with caution.

Assessing Mongolian gerbil emotional behavior: effects of two shock intensities and response-independent shocks during an extended inhibitory-avoidance task.

Despite step-down inhibitory avoidance procedures that have been widely implemented in rats and mice to study learning and emotion phenomena, performance of other species in these tasks has received less attention. The case of the Mongolian gerbil is of relevance considering the discrepancies in the parameters of the step-down protocols implemented, especially the wide range of foot-shock intensities (i.e., 0.4-4.0 mA), and the lack of information on long-term performance, extinction effects, and behavioral patterning during these tasks. Experiment 1 aimed to (a) characterize gerbils' acquisition, extinction, and steady-state performance during a multisession (i.e., extended) step-down protocol adapted for implementation in a commercially-available behavioral package (Video Fear Conditioning System-MED Associates Fairfax, VT, USA), and (b) compare gerbils' performance in this task with two shock intensities - 0.5 vs. 1.0 mA-considered in the low-to-mid range. Results indicated that the 1.0 mA protocol produced more reliable and clear evidence of avoidance learning, extinction, and reacquisition in terms of increments in freezing and on-platform time as well as suppression of platform descent. Experiment 2 aimed to (a) assess whether an alternate protocol consisting of a random delivery of foot shocks could replicate the effects of Experiment 1 and (b) characterize gerbils' exploratory behavior during the step-down task (jumping, digging, rearing, and probing). Random shocks did not reproduce the effects observed with the first protocol. The data also indicated that a change from random to response-dependent shocks affects (a) the length of each visit to the platform, but not the frequency of platform descends or freezing time, and (b) the patterns of exploratory behavior, namely, suppression of digging and rearing, as well as increments in probing and jumping. Overall, the study demonstrated the feasibility of the extended step-down protocol for studying steady performance, extinction, and reacquisition of avoidance behavior in gerbils, which could be easily implemented in a commercially available system. The observation that 1.0 mA shocks produced a clear and consistent avoidance behavior suggests that implementation of higher intensities is unnecessary for reproducing aversive-conditioning effects in this species. The observed patterning of freezing, platform descents, and exploratory responses produced by the change from random to periodic shocks may relate to the active defensive system of the gerbil. Of special interest is the probing behavior, which could be interpreted as risk assessment and has not been reported in other rodent species exposed to step-down and similar tasks.

Survey of intestinal helminths collected from pet rodents in México.

In this survey, intestinal helminths from pet rodents in Mérida, México, were analyzed. A total of 46 mice Mus musculus, 28 hamsters Mesocricetus auratus, 23 rats Rattus norvegicus, and 1 gerbil Meriones unguiculatus were purchased from six pet shops and one black market for wildlife in the city of Mérida. The overall prevalence of helminths in rodents was 61.2% (60/98). Six species of helminths were identified: the zoonotic cestode Rodentolepis nana, and the nematodes Aspiculuris tetraptera, Dentostomella translucida, Syphacia obvelata, Syphacia mesocriceti, and Syphacia muris. Of the 60 infected rodents, 25 (41.7%) harbored 2 or 3 species of helminths. Rodentolepis nana was found in 4.3% of mice and 17.9% of hamsters. This is the first report of infection with S. muris in pet rats. Considering the close physical contact between pet rodents and humans, the presence of R. nana in pets represents a potential risk of transmission, especially to children and immunocompromised individuals.

Corticosterone influences gerbil (Meriones unguiculatus) prostatic morphophysiology and alters its proliferation and apoptosis rates.

Glucocorticoids (GCs) are hormones that are widely used in medicine; but although side effects are generally recognised, little is known about the precise mechanisms that is implicated in many of these side effects. Furthermore, GCs are highly correlated with stress and behaviour disorders. This study evaluated the effects of the glucocorticoid corticosterone on the ventral prostate of the Mongolian gerbil. Male gerbils (Meriones unguiculatus) (n = 5) received intraperitoneal injections of saline or corticosterone in doses of 0.5 mg/kg/day and 1.5 mg/kg/day for 5 days; while some of the animals were killed immediately after the treatment, the others were killed 5 days after the treatment period. The data show that corticosterone influences the structure and functionality of this organ. This hormone has anti-proliferative and anti-apoptotic properties in the prostate. In addition, the frequencies of the androgen (AR), oestrogen (ERα, ERß) and glucocorticoid (GR) receptors changed. The frequencies of AR, GR and ERß decreased in the Ct1/5 group; in the groups with rest period, the frequencies of GR increased and ERß decreased in the epithelium. Changes in the proliferative index, apoptotic index and receptor activity may have contributed to the emergence of prostatic morphological alterations, such as the presence of cellular debris and inflammatory cells. Different doses of corticosterone had variable effects on the prostate, with a higher dose showing subtler effects and a lower dose showing more striking effects. The corticosterone effects on nuclear receptors were reverted or attenuated after a rest period, which was not observed for proliferation and apoptosis. In summary, we have demonstrated that corticosterone might influence the prostatic morphophysiology and that these changes may be linked in some way to the altered receptor distribution.

The mongolian gerbil (Meriones unguiculatus) as a model for inflammation-promoted prostate carcinogenesis.

One of the recognized issues in prostate cancer research is the lack of animal models allowing the research of pathological, biochemical, and genetic factors in immunocompetent animals. Our research group has successfully employed the gerbil in several studies for prostate diseases. In the present work, we aimed to analyze the effect of chronic bacterial inflammation on N-methyl-N-nitrosourea (MNU)-induced prostate carcinogenesis in gerbils. Histopathological assessment of the prostatic complex revealed that treatment combinations with MNU plus testosterone or bacterial infection resulted in a promotion of prostate cancer, with bacterial inflammation being more effective in increasing premalignant and malignant tissular alterations than testosterone in the prostate. Furthermore, chronic bacterial inflammation itself induced premalignant lesions in the ventral lobe and increased their frequency in the dorsolateral lobe as well as malignant lesions in the ventral prostate. These animals showed a rich inflammatory microenvironment, characterized as intraluminal and periductal foci. These data indicate that chronic inflammation induced by Escherichia coli acts as a potent tumor promoter, in the early stages of carcinogenesis in the gerbil, in line with the hypothesis of inflammation supporting several steps of tumor development in the prostate gland.