Studies of diabetes mellitus in the streptozotocin rat model suggest that sexual dysfunctions may result from diabetes-induced alterations of the neuroendocrine-reproductive tract axis. Our investigation was performed to better define the effects of short-term hyperglycaemia on rat epididymal sperm quantity, quality and transit time, using both natural mating and artificial in utero insemination protocols. Male rats were made diabetic with streptozotocin (sc, 40 mg/kg), whereas controls received vehicle. Sexual behaviour was tested after 15 days and sperm fertilizing ability was checked 22 days after the injection through natural mating and artificial in utero insemination. Other parameters such as daily sperm production, testosterone levels, as well as sperm morphology and motility were also investigated. Fifty per cent of the diabetic animals showed no copulatory behaviour during tests and the number of animals reaching ejaculation was smaller in the diabetic group when compared with the control group (33% vs. 83%). Diabetes resulted in decreased body and reproductive organ weights, as well as diminished sperm counts in the testis and epididymis, that were associated with diminution of plasmatic testosterone levels. After natural mating, there was a decrease in the fertility in the diabetic adult male rats (25.5%) compared with control animals (81.5%). However, distal cauda epididymal sperm from diabetic rats displayed normal fertilization ability (91.5%) using in utero insemination. There were no effects of hyperglycaemia on sperm transit time in the epididymis and on spermatogenesis. Our results indicate that diabetes mellitus produces reproductive dysfunction, but does not compromise sperm fertilizing ability in the cauda epididymis in this experimental model.

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The Meriones unguiculatus (Mongolian) gerbil has demonstrated significant prostatic responses to hormonal treatments, and to drugs against human prostatic hyperplasia. Spontaneous neoplasia develops in the older animals. Thirty gerbils (age 18 months) were divided into non-affected and prostatic lesion bearers and the prostate lesions were evaluated morphologically, immunohistochemically and quantitatively. The most frequent changes were in epithelial sites and, namely prostatic intraepithelial neoplasias, microinvasive carcinomas and adenocarcinomas. In the stromal compartment, cellular hyperplasia, when verified, was always associated with the sites of anomalous epithelium. Additionally, larger deposition of collagen fibrils, generating stromal fibrosis, was found in all the old gerbils analysed. The quantitative analysis showed that prostatic tissue proportions differed in altered areas, being specific for each lesion type. Isolated nuclear and nucleolar parameters were not effective in diagnosing the malign potential of lesions. However, the cellular proliferation and death indexes indicated larger cellular turnover in invasive lesions such as carcinomas. With these analyses, it could be verified that old gerbils present high propensity to develop spontaneous prostate changes and this may aid in a better understanding of the biological behaviour of human prostate cancer.

Carcinogenesis is frequently linked to genetic background, however, exposure to environmental risk factors has gained attention as the etiologic agent for several types of cancer, including prostate. The intrauterine microenvironment has been described as a preponderant factor for offspring health; and maternal exposure to insult has been linked to chronic disease in older offspring. Using a model of maternal exposure to low protein diet (LPD; 6% protein), we demonstrated that impairment of offspring rat prostatic growth on postnatal day (PND) 21 was associated with prostate carcinogenesis in older offspring (PND 540). One explanation is that maternal LPD consumption exposed offspring to an estrogenic intrauterine microenvironment, which potentially sensitized prostate cells early during glandular morphogenesis, increasing cellular response to estrogen in older rats. The onset of accelerated prostatic growth, observed on PND 21, associated with an unbalanced estrogen/testosterone ratio and increased circulating IGF-1 in older offspring appears to contribute to the development of prostate carcinoma in gestational groups on low protein (GLP) and gestational and lactational low protein (GLLP) diets (33% and 50%, respectively). Our study strongly indicated maternal exposure to LPD as a potential risk factor for induction of slow-growing prostate carcinogenesis in rat offspring later in life.

Background Here, we have demonstrated that gestational low-protein (LP) intake offspring present lower birth weight, reduced nephron numbers, renal salt excretion, arterial hypertension, and renal failure development compared to regular protein (NP) intake rats in adulthood. We evaluated the expression of various miRNAs and predicted target genes in the kidney in gestational 17-days LP (DG-17) fetal metanephros to identify molecular pathways involved in the proliferation and differentiation of renal embryonic or fetal cells. Methods Pregnant Wistar rats were classified into two groups based on protein supply during pregnancy: NP (regular protein diet, 17%) or LP diet (6%). Renal miRNA sequencing (miRNA-Seq) performed on the MiSeq platform, RT-qPCR of predicted target genes, immunohistochemistry, and morphological analysis of 17-DG NP and LP offspring were performed using previously described methods. Results A total of 44 miRNAs, of which 19 were up and 25 downregulated, were identified in 17-DG LP fetuses compared to age-matched NP offspring. We selected 7 miRNAs involved in proliferation, differentiation, and cellular apoptosis. Our findings revealed reduced cell number and Six-2 and c-Myc immunoreactivity in metanephros cap (CM) and ureter bud (UB) in 17-DG LP fetuses. Ki-67 immunoreactivity in CM was 48% lesser in LP compared to age-matched NP fetuses. Conversely, in LP CM and UB, β-catenin was 154%, and 85% increased, respectively. Furthermore, mTOR immunoreactivity was higher in LP CM (139%) and UB (104%) compared to that in NP offspring. TGFβ-1 positive cells in the UB increased by approximately 30% in the LP offspring. Moreover, ZEB1 metanephros-stained cells increased by 30% in the LP offspring. ZEB2 immunofluorescence, although present in the entire metanephros, was similar in both experimental groups. Conclusions Maternal protein restriction changes the expression of miRNAs, mRNAs, and proteins involved in proliferation, differentiation, and apoptosis during renal development. Renal ontogenic dysfunction, caused by maternal protein restriction, promotes reduced reciprocal interaction between CM and UB; consequently, a programmed and expressive decrease in nephron number occurs in the fetus.

Environmental exposure to phthalates during intrauterine development might increase susceptibility to neoplasms in reproductive organs such as the prostate. Although studies have suggested an increase in prostatic lesions in adult animals submitted to perinatal exposure to phthalates, the molecular pathways underlying these alterations remain unclear. Genome-wide levels of mRNAs and miRNAs were monitored with RNA-seq to determine if perinatal exposure to a phthalate mixture in pregnant rats is capable of modifying gene expression during prostate development of the filial generation. The mixture contains diethyl-phthalate, di-(2-ethylhexyl)-phthalate, dibutyl-phthalate, di-isononyl-phthalate, di-isobutyl-phthalate, and benzylbutyl-phthalate. Pregnant females were divided into 4 groups and orally dosed daily from GD10 to PND21 with corn oil (Control: C) or the phthalate mixture at 3 doses (20 μg/kg/day: T1; 200 μg/kg/day: T2; 200 mg/kg/day: T3). The phthalate mixture decreased anogenital distance, prostate weight, and decreased testosterone level at the lowest exposure dose at PND22. The mixture also increased inflammatory foci and focal hyperplasia incidence at PND120. miR-184 was upregulated in all treated groups in relation to control and miR-141-3p was only upregulated at the lowest dose. In addition, 120 genes were deregulated at the lowest dose with several of these genes related to developmental, differentiation, and oncogenesis. The data indicate that phthalate exposure at lower doses can cause greater gene expression modulation as well as other downstream phenotypes than exposure at higher doses. A significant fraction of the downregulated genes were predicted to be targets of miR-141-3p and miR-184, both of which were induced at the lower exposure doses.

In the present study we evaluated the toxic effects on the male adult rat prostate of DBP exposure during fetal and lactational periods, because although many studies have addressed the influence of phthalates on the male reproductive system, only a few have discussed their possible effects on prostate development. Pregnant females were distributed into two experimental groups: Control (C) and Treated (T). The females of the T group received DBP (100mg/kg, by gavage) from gestation day 12 to postnatal day 21, while C rats received the vehicle (corn oil). In adulthood (90 days old), the animals were euthanized. The serum and testicular testosterone levels were measured. Ventral prostate was removed and weighed. Distal segment fragments of the ventral prostate were fixed and processed for histochemistry and immunohistochemistry to detect androgen receptor (AR) and Ki67 antigens. Protein extraction from ventral prostate fragments was performed for AR immunoblotting and Gelatin zymography for MMP-2 and MMP-9 (MMP, metalloproteinase). Stereological and histopathological analyses were also performed. Serum and testicular testosterone levels and prostate weight were comparable between groups. In the T group the relative proportions (%) of epithelial (C=32.86; T=42.04*) and stromal (C=21.61; T=27.88*) compartments were increased, while the luminal compartment was decreased (C=45.54; T=30.08*), *p<0.05. InT, disseminated inflammatory infiltrate in the stroma, associated or not with epithelial dysplasia and PIN (Prostatic Intraepithelial Neoplasia), was observed. Increases in AR expression, proliferation index and metalloproteinase 9 (MMP-9) activity were noted in T animals. In some T animals, collagen fibrils accumulated adjacent to the epithelium. As far as we are aware, this is the first report in the literature showing that phthalates could play a role in proliferative and inflammatory disorders of the rat prostate.

Our findings show that MPM delays prostate development, growth and maturation until adulthood, probably as a result of low testosterone stimuli. The higher incidence of cellular dysplasia and prostatitis suggests that MPM increases prostate susceptibility to diseases with aging.