Postpubertal Male Rats Research Articles

Role of reorganization of mitochondria structure in age-dependent changes of adrenal cortex function

Steroidogenic activity of adrenal cortical cells is known to change significantly during postnatal development. Age-dependent changes of mitochondrial apparatus and its impact in secretory activity of the adrenal cortex are less studied. The aim was to uncover age-dependent mitochondrial dynamics in rat glomerulosa, fasciculata and reticularis cells, and to assess them together with changes in adrenal cortex morphology and function. Pubertal and postpubertal male Wistar rats were used in the research. Quantitative parameters of adrenal cortex morphology and fine structure of adrenocortical cells were examined by light and transmission electron microscopy. Production of adrenal hormones was evaluated by enzyme-linked immunosorbent assay. Discrete age-dependent changes of mitochondrial dynamics was revealed. These changes were found more sufficient for hormone production then alterations in morphology of adrenocortical zones. Association of changes in mitochondrial structure with intensity of hormone secretion demonstrate that morphological studies of adrenal cortex requires examination of fine structure for correct assessment of adrenal development.

The influence of human chorionic gonadotropin on hormonal and haematological profile of postpubertal male albino rats exposed to chronic oral administration of alcohol

This study evaluated the influence of human chorionic gonadotropin on hormonal and haematological profile of postpubertal male albino rats exposed to chronic oral administration of alcohol. Twenty-four mature male albino rats were assigned to four groups (n=6). Group A was the control, given distilled water, Group B was given 30% ethanol (8 ml/kg) orally 3 times a week, Group C was given human chorionic gonadotropin (HcG) (50 IU/kg) subcutaneously 3 times a week and Group D was given HcG (50 IU/kg) subcutaneously + 30% ethanol (8 ml/kg) orally 3 times a week. The study was for 10 weeks, and hormonal profile and haematology were determined. The follicle stimulating hormone of Group B decreased significantly (P<0.05) when compared to Groups A, C and D. The luteinizing hormone was significantly lower (P<0.05) in Group B when compared to Groups A, C and D. The testosterone level was significantly higher (P<0.05) in Group D when compared to Groups A, B and C. The results obtained from haematology indicated that haemoglobin concentration of Group B was significantly lower (P<0.05) when compared to Groups A, C and D. Ethanol significantly reduced (P<0.05) platelets when compared to Groups A, C and D. There was a significant reduction (P<0.05) in the neutrophils and lymphocytes in Group B when compared to Groups A, C and D. The study showed that HcG improves the level of male hormones and haematology in postpubertal albino rats exposed to chronic alcohol administration.

Introduction pages

Notulae Scientia Biologicae (http://www.notulaebiologicae.ro), Issue 4, Volume 12, 2020: The papers published in this issue represent interesting novelties in different topics of life science. Among the exciting researches or reviews, we invite readers to find news about: The influence of human chorionic gonadotropin on hormonal and haematological profile of postpubertal male albino rats exposed to chronic oral administration of alcohol; Phylogenetic observation in Ariidae, Bagridae and Plotosidae catfishes by COI gene sequence analysis; A preliminary study and new distributional records of family Erebidae (Leach, [1815]) (Lepidoptera: Noctuoidea) from Aligarh, Uttar Pradesh, India; Evaluation of pearl millet (Pennisetum glaucum L. (R. Br.)) landraces for resistance to stem borer (Coniesta ignefusalis Hampson.) infestation; Photochemical responses of cucumber (Cucumis sativus L.) plants to heat stress; Vegetative propagation of cornelian cherry (Cornus mas L.) selections; Effect of pre-storage hot air and hot water treatments on post-harvest quality of mango (Mangifera indica Linn.) fruit; Effect of snowmelt regime on phenology of herbaceous species at and around treeline in Western Himalaya, India etc.

Cell Type- and Sex-Dependent Transcriptome Profiles of Rat Anterior Pituitary Cells.

Understanding the physiology and pathology of an organ composed of a variety of cell populations depends critically on genome-wide information on each cell type. Here, we report single-cell transcriptome profiling of over 6,800 freshly dispersed anterior pituitary cells from postpubertal male and female rats. Six pituitary-specific cell types were identified based on known marker genes and characterized: folliculostellate cells and hormone-producing corticotrophs, gonadotrophs, thyrotrophs, somatotrophs, and lactotrophs. Also identified were endothelial and blood cells from the pituitary capillary network. The expression of numerous developmental and neuroendocrine marker genes in both folliculostellate and hormone-producing cells supports that they have a common origin. For several genes, the validity of transcriptome analysis was confirmed by qRT-PCR and single cell immunocytochemistry. Folliculostellate cells exhibit impressive transcriptome diversity, indicating their major roles in production of endogenous ligands and detoxification enzymes, and organization of extracellular matrix. Transcriptome profiles of hormone-producing cells also indicate contributions toward those functions, while also clearly demonstrating their endocrine function. This survey highlights many novel genetic markers contributing to pituitary cell type identity, sexual dimorphism, and function, and points to relationships between hormone-producing and folliculostellate cells.

Estrogen Modulates Ethanol-Induced Memory Deficit in Postpubertal Adolescent Rats.

Our laboratory and others have reported that ethanol (EtOH) impairs hippocampus-associated memory formation in prepubertal adolescent rats. Acute alcohol exposure in humans produces a syndrome of memory loss ("blackouts") that is similar to impairments caused by hippocampal damage. The ability to form new long-term explicit memories is affected, but not short-term memory storage or recall of information from long-term storage. Alcohol-induced memory impairment, similar to teenage alcohol blackouts, has been shown in prepubertal adolescent rodents. In the present study, EtOH's effect on contextual fear memory was examined in postpubertal rats. In Experiment 1, intact male and female postpubertal rats were treated with an acute intraperitoneal injection of EtOH or vehicle. Thirty minutes later, rats were trained in the fear conditioning paradigm, and 24hours after training, all rats were tested for contextual fear conditioning. In Experiment 2, groups of intact postpubertal female rats were treated with a single injection of EtOH, or vehicle, during different phases of the estrus cycle and tested for fear conditioning. In Experiment 3, groups of postpubertal female rats were ovariectomized (OVX) and were given hormonal supplementation (estrogen with or without progesterone) and tested for EtOH-induced memory formation. Additional controls included sham-operated, oil-treated postpubertal female rats. In Experiment 4, intact postpubertal male rats were administered exogenous estrogen alone or together with progesterone and tested for EtOH-induced contextual memory formation. Following an acute EtOH exposure, intact postpubertal female rats exhibited significant impairments in contextual fear conditioning. But acute EtOH had little effect on contextual fear conditioning in intact postpubertal males. EtOH impaired memory formation during all phases of the estrus cycle except during estrus phase when blood levels of estrogen are low. Ovariectomized rats did not show any EtOH-induced impairment in contextual freezing compared to vehicle-treated ovariectomized rats. In female rats, bilateral ovariectomy eliminated EtOH-induced memory deficit and estrogen replacement reintroduced EtOH-induced memory impairment. Although postpubertal male rats were insensitive to EtOH's effect on contextual fear conditioning, but when treated with exogenous estrogen, they performed poorly in the contextual memory task. Together, these data suggest that the female gonadal hormone estrogen is an important modulator of EtOH-induced cognitive behavior in postpubertal female and male rats, and that it may play an important role in teenage alcohol blackout.

Male mammary gland development and methylation status of estrogen receptor alpha in Wistar rats are modified by the developmental exposure to a glyphosate-based herbicide

Postnatal treatment with glyphosate-based herbicides (GBHs) induces endocrine-disrupting effects on the male rat mammary gland. In this study, the effects of developmental exposure to GBH on mammary gland growth and development, and the possible molecular mechanisms involved, were evaluated in pre- and post-pubertal male rats. To this end, pregnant rats were orally exposed through the food to 0, 3.5 or 350 mg GBH/kg bw/day from gestational day 9 until weaning. Mammary gland development and estradiol (E2) and testosterone (T) serum levels of male offspring were evaluated on postnatal day (PND)21 and PND60. Besides, prolactin (PRL) serum levels, proliferation index, androgen (AR) and estrogen receptor alpha (ESR1) expression, ESR1 alternative transcript mRNA levels, and DNA methylation status of ESR1 promoters were assessed on PND60. No differences between groups were observed in mammary gland development at PND21 or in E2 and T levels on both PNDs studied. On PND60, GBH3.5-exposed animals presented similar mammary gland histology but higher AR protein expression than controls, whereas GBH350-exposed males presented a less developed mammary gland, accompanied by a lower proliferation index, similar AR levels, and slightly increased PRL serum levels than controls. In both exposed groups, ESR1 expression was lower than in control rats, being lower in GBH350-exposed rats. GBH also altered the abundance of ESR1 transcript variants by hypermethylation of ESR1 promoters. GHB3.5 decreased only ESR1-OS expression, whereas GBH350 affected ESR1-O, OT and E1 expression. Our results show that developmental exposure to GBH induces epigenetic changes in ESR1, which could be responsible for the altered male mammary gland development observed in GBH350-exposed animals.

17 beta-estradiol synthesis modulates cerebellar dependent motor memory formation in adult male rats.

Neurosteroid 17 beta-estradiol (E2) is a steroid synthesized de novo in the nervous system that might influence neuronal activity and behavior. Nevertheless, the impact of E2 on the functioning of those neural systems in which it is slightly synthesized is less questioned. The vestibulo-ocular reflex (VOR) adaptation, may provide an ideal arena for investigating this issue. Indeed, E2 modulates cerebellar parallel fiber-Purkinje cell synaptic plasticity that underlies encoding of VOR adaptation. Moreover, aromatase expression in the cerebellum of adult rodents is maintained at very low levels and localized to Purkinje cells. The significance of age-related maintenance of low levels of aromatase expression in the cerebellum on behavior, however, has yet to be explored. Our aim in this study was to determine whether E2 synthesis exerts an effective and persistent modulation of VOR adaptation in adult male rats. To answer this question, we investigated the acute effect of blocking E2 synthesis on gain increases and decreases in VOR adaptation using an oral dose (2.5 mg/kg) of the aromatase inhibitor Letrozole in peri-pubertal and post-pubertal male rats. We found that Letrozole acutely impaired gain increases and decreases in VOR adaptation without altering basal ocular-motor performance and that these effects were similar in peri-pubertal and post-pubertal rats. Thus, in adult male rats neurosteroid E2 effectively modulates VOR adaptation in both of the periods studied. These findings imply that the adult cerebellum uses E2 synthesis for modulating motor memory formation and suggest that low and extremely localized E2 production may play a role in adaptive phenomena.

Postnatal exposure to a glyphosate-based herbicide modifies mammary gland growth and development in Wistar male rats

Our aim was to evaluate whether postnatal exposure to a glyphosate-based herbicide (GBH) modifies mammary gland development in pre- and post-pubertal male rats. From postnatal day 1 (PND1) to PND7, male rats were injected subcutaneously every 48 h with either saline solution (vehicle) or 2 mg GBH/kg·bw. On PND21 and PND60, mammary gland and blood samples were collected. Estradiol (E2) and testosterone (T) serum levels, mammary gland histology, collagen fiber organization, mast cell infiltration, proliferation index, and estrogen (ESR1) and androgen receptor (AR) expression levels were evaluated. At PND21, GBH-exposed male rats exhibited greater development of the mammary gland with increased stromal collagen organization and terminal end buds (TEBs) compared to control rats. At PND60, the number of TEBs remained high and was accompanied by an increase in mast cell infiltration, proliferation and ESR1 expression in GBH-exposed male rats. In contrast, no effects were observed in E2 and T serum levels and AR expression in both days studied. Our results showed that a postnatal subacute treatment with GBH induces endocrine-disrupting effects in the male mammary gland in vivo, altering its normal development.

Early postnatal exposure to endosulfan interferes with the normal development of the male rat mammary gland

Our aim was to evaluate whether postnatal exposure to endosulfan (ENDO) modifies mammary gland (MG) development in pre- and post-pubertal male rats. From postnatal day 1 (PND1) to PND7, male rats were injected subcutaneously every 48h with either corn oil (vehicle) or 600μg ENDO/kg.bw. On PND21 and PND60, MG and blood samples were collected. Estradiol (E2) and testosterone (T) serum levels, MG histology, collagen fiber organization, proliferation index, and estrogen (ESR1) and androgen receptor (AR) expressions were evaluated. On PND21, E2 and T levels were similar between groups, whereas MG area, perimeter, number of terminal end buds and ESR1 expression were increased in ENDO-exposed rats. These changes were associated with alveolar development and increased organized collagen in the stroma. On PND60, a higher proliferation index in ENDO-exposed rats was correlated with a more developed lobuloalveolar structure. Hyperplastic alveoli and, hyperplastic ducts surrounded by a dense stroma were also observed in this group. T levels and ESR1 expression were similar between groups, whereas E2 levels and AR expression were decreased in ENDO-exposed rats. The exposure to ENDO in the first week of life interferes with the normal development of the MG and induces pre-malignant lesions in post-pubertal male rats.

Safety evaluation of supratherapeutic dose of Maytenus ilicifolia Mart. ex Reissek extracts on fertility and neurobehavioral status of male and pregnant rats

Maytenus ilicifolia Mart. ex Reissek is a plant commonly used in folklore medicine in the management of gastric diseases in South America. This study explores the effects of a supratherapeutic dose of aqueous and ethanol extracts of M. ilicifolia (1360 mg/kg) on fertility and neurobehavioral status in male and pregnant rats. A battery of sensory-motor developmental endpoints was carried out to assess impairments on pups of dams orally treated with the aqueous extract of M. ilicifolia during the organogenesis period of pregnancy (GD 9 through GD 14). The neuromotor maturation reflexes and physical developments of the offspring were not significantly different between the groups (p < 0.05). Also, the hippocampal morphology revealed no indices of cell loss in the CA1, CA2, CA3 and CA4 areas. As second protocol, some fertility aspects were investigated in young post pubertal male Wistar rats treated with the ethanol extract for 30 days. The semen quality and testicular tissue morphology of male rats treated with the ethanol extract of M. ilicifolia remained unaffected upon treatment. Thus, the results indicate that the high-dose of M. ilicifolia extracts have no neurotoxic potential on offspring and seem not to affect the sperm quality of male rats.

Effects of Post-Weaning Consumption of Soy Isoflavones on Prepubertal and Postpubertal Serum Levels of Some Reproductive Hormones of Male Wistar Rats

Chemically, soy contains a group of phytoestrogens called isoflavones, pre-dominantly genistein and daidzein. The aim of the present study was to determine the effects of post weaning consumption of dietary soy isoflavones on prepubertal and postpubertal serum levels of some reproductive hormones of male Wistar rats. The study involved investigating the effects of different doses of isoflavones in the diet. Male rats were weaned on either soy isoflavone free diet or on isoflavone containing diets, formulated by adding increasing amounts of Novasoy, a commercially available isoflavone supplement to the isoflavone free diet to give varying concentrations of isoflavones. Three isoflavone containing diets were used and these had 74.5, 235.6 and 1046.6 mg total isoflavones/kg pelleted diet. These diets represented the isoflavone concentration lower, equal to and more than that found in soy-based infant formulas respectively. The results obtained showed that; administration of low doses soy isoflavones (74.5 mg/kg) produced significant (p < 0.05) increase in serum Antimullerian Hormone levels both in prepubertal and post pubertal rats, when compared to the control groups. Administration of moderate doses of isoflavones (235.6 mg/kg) produced significant (p < 0.05) increase in serum levels of Antimullerian Hormone and Inhibin in both prepubertal and post pubertal rats when compared to the control groups. Administration of high doses of isoflavones (1046.6 mg/kg) produced significant (p < 0.05) increase in serum levels of Inhibin in both prepubertal and post pubertal rats when compared to the control groups. From this study, it was concluded that post-weaning consumption soy isoflavones produced significant changes in serum Inhibin and Antimullerian Hormone both in prepubertal and post pubertal male Wistar rats and the changes were dose dependent.

PHYTOESTROGENS EFFECT ON SEXUAL HORMONES LEVEL AND FERTILITY OF RATS

The influence of 30-day application of phytoestrogens compound to postpubertal male and female rats on the level of sexual hormones, gametes maturation and fertilization capacity was experimentally studied. Long-term phytoestrogenes supplies into animal’s organism bring out substantial changes in the level of sexual hormones. In females different estradiol contents are levelled at the estrus-diestrus stages that is typical for intact females. In males there was a considerable increase of estradiol, in a lesser degree — testosterone. Hence, the testosterone-esrtadiol ratio is altered. Morphological structural changes in male and female gametes, decreased spermatozoa motility, impaired embryonic implantation, a high rate of embryonic mortality are observed.

Stimulatory response of pineal-thyroid nuclear morphology and function following adrenocortical modulation in rat (Rattus rattus)

The relationship between pineal and thyroid in response to the adrenocortical modulation is poorly understood. In the present study post pubertal male rats were treated with natural and synthetic corticoids and an antiadrenal agent mitotane. Hydroxycortisone was administered at a dose of 4 mg / 100 g b.w., dexamethasone 2 mg / 100 g b.w. and mitotane 3 mg / 100 g b.w. for fifteen consecutive days. Our data revealed that both the corticoids, hydroxycorticosterone and dexamethasone induced hyperactivity of pineal and thyrofollicular cell morphology. The functional relation between the cells of the pineal parenchyma and thyroid follicles were noted. Similar results were induced by mitotane, an antiadrenal agent. It is concluded, that our present study indicates a mutual relationship between the pineal and the thyroid gland karyomorphological and functional parameters in response to corticoids and an antiadrenal agent in post pubertal male rat (Rattus rattus).

Chronic insulin treatment, but not chronic ACTH administration increases plasma dehydroepiandrosterone sulfate levels in adolescent male rats.

The chronic effect of daily i. m. administration of ACTH (1 U/kg bodyweight (BW), group A) and of insulin (15/kg BW, group B) on circulating dehydroepiandrosterone sulfate (DHEA-S) and testosterone was investigated in postpubertal male Wistar rats. NaCl-injected animals served as controls (group C). After at least 8 days under the respective hormone or NaCl treatment "basally" circulating testosterone levels were slightly suppressed in insulin- (1.56 +/- 0.86 ng/ml) and markedly reduced (0.54 +/- 0.21 ng/ml) in ACTH-treated rats vs. controls (2.33 +/- 0.69 ng/ml). DHEA-S levels, however, nearly doubled under chronic insulin administration (0.4 +/- 0.18 ng/ml) in comparison to the groups A (0.22 +/- 0.11 ng/ml) and C (0.23 +/- 0.09 ng/ml). Food intake and weight gain were also elevated (vs. groups A and C) as were the basal plasma corticosterone levels (vs. group C) in insulin treated rats. Following an acute ACTH stimulation test (12 U/kg BW i.m.) performed in all three treatment groups, plasma DHEA-S showed a further increase in the animals receiving insulin (0.75 +/- 0.32 ng/ml), whereas no response was detectable in rats from group A (0.27 +/- 0.13 ng/ml) or C (0.24 +/- 0.11 ng/ml). Further measurements of corticosterone or testosterone responses following endocrinological stimulation tests with supraphysiological doses of either ACTH or human chorionic gonadotropin (hCG) indicated that a lowering in the catabolism (metabolic clearance) of corticosteroids or androgens could not be the cause for the elevated DHEA-S levels seen after daily insulin injections.(ABSTRACT TRUNCATED AT 250 WORDS)

Arginine vasopressin regulation in pre- and postpubertal male rats by the androgen metabolite 3β-diol

Arginine vasopressin (AVP) is a nonapeptide expressed in several brain regions. In addition to its well-characterized role in osmoregulation, AVP regulates paternal behavior, aggression,circadian rhythms, and the stress response. In the bed nucleus of the stria terminalis (BST), AVP gene expression is tightly regulated by gonadal steroid hormones. However, the degree by which AVP is regulated by gonadal steroid hormones in the suprachiasmatic nucleus (SCN) and medial amygdala (MeA) is unclear. Previous studies have shown that AVP expression in the brain of gonadectomized rats is restored with testosterone, 17beta-estradiol, and 5alpha-dihydrotestosterone(DHT) replacement. In addition, we have demonstrated that 3beta-diol, a metabolite of DHT,increased AVP promoter activity in a neuronal cell line and that the effects of 3beta-diol on AVP promoter activity were mediated by estrogen receptor-beta. To test whether 3beta-diol has a physiological role in the regulation of central AVP expression in vivo, we gonadectomized pre- and postpubertal male rats and followed with once daily injections of estradiol benzoate (EB),DHT-propionate, 3beta-diol-dipropionate, or vehicle. The SCN, BST, and MeA were analyzed for AVP mRNA expression using in situ hybridization. In the BST, intact juveniles had significantly fewer AVP-expressing cells than adults. GDX abolished all AVP mRNA expression in the BST in both age groups, whereas treatment with EB restored >80% and DHTP <10% of the AVP expression. Interestingly, 3beta-diol-proprionate was more effective at inducing AVP expression in juveniles than in adults, suggesting that the regulation of AVP by 3beta-diol might be age dependent [corrected].

Neonatal ventral hippocampal lesions in male and female rats: Effects on water maze, locomotor activity, plus-maze and prefrontal cortical GABA and glutamate release in adulthood

Schizophrenia is characterized by diverse behavioural and neurochemical abnormalities that may be differentially expressed in males and females. Male rats with neonatal ventral hippocampal lesions (nVHL) have commonly demonstrated behavioural and neurochemical abnormalities similar to those in schizophrenia. Fewer studies have used female rats. We investigated the hypothesis that male and female nVHL rats will demonstrate behavioural abnormalities accompanied by decreased GABA and l-glutamate release in the prefrontal cortex (PFC). On postnatal day (P) 7 rats received VH injections of ibotenate (3.0 μg/0.3 μl/side; n = 18) or saline ( n = 21) or no injections ( n = 22). On P56, rats began water-maze, locomotor activity and elevated plus maze testing, and were then sacrificed for potassium-evoked GABA and l-glutamate release from PFC slices. nVHL rats showed impaired performance in water maze acquisition and match-to-sample tasks, increased spontaneous and amphetamine-induced locomotor activity and increased percent open-arm time. These behavioural changes were similar in males and females. These effects were accompanied by significantly reduced potassium-evoked l-glutamate release in male and female nVHL rats relative to controls, and non-significantly lower GABA release. Findings support the notion that behavioural abnormalities in post-pubertal male and female nVHL rats are associated with decreases in PFC neurotransmitter release.

Changes in the pattern of exploratory behavior are associated with the emergence of social dominance relationships in male rats

This study examined the effect of the establishment of dominance relationships and subordination on exploratory behavior for both postpubertal and adult male rats. Prior to an open field test, subjects were housed either in isolation (IS) or in littermate pairs (PS) with mild dominance relationships without overt victory or defeat, or in pairs with clear hierarchical relationships as dominants (DOM) or subordinates (SUB). Stretch-attend postures and entries into the center area of the open-field were measured as an index of passive and active exploratory behavior, respectively, and crossings in the peripheral area were counted as activity. SUB rats, both postpubertal and adult, displayed less activity and lower levels of active exploratory behavior, whereas adult IS rats showed higher levels of active exploratory behavior compared to the other groups. Furthermore, both DOM and PS rats exhibited a more passive pattern of exploratory behavior in adulthood than in postpuberty. Thus the results show that an increase in the active exploratory pattern is inhibited by the establishment of social relationships among adult rats, while a decrease in activity is a primarily effect of subordination. The capacity to change exploratory patterns following subordination is found even in the postpubertal stage when adultlike social relationships have not yet appeared.

Gender and puberty interact on the stress-induced activation of parvocellular neurosecretory neurons and corticotropin-releasing hormone messenger ribonucleic acid expression in the rat.

Individual variations in hypothalamic-pituitary-adrenal (HPA) function are most evident at or beyond the time of puberty, when marked changes in sex steroid release occur. To explore the nature by which gender differences in HPA function emerge we examined in prepubertal (approximately 30-d-old) and postpubertal (approximately 60-d-old) male and female rats HPA activity under basal conditions and in response to 30 min of restraint. Within the ACTH-regulating, medial parvocellular portion of the paraventricular nucleus, restraint-induced Fos protein and arginine vasopressin heteronuclear RNA were lower in 60- than in 30-d-old males. No such age-related shift in the response of these synaptic and transcriptional markers of cellular activation occurred in female rats. Basal CRH mRNA expression levels in the paraventricular nucleus increased with age in female but not male rats. Conversely, only male rats showed an age-related increase in basal CRH mRNA in the central amygdala, suggesting that neuronal and neurosecretory CRH-expressing cell types are subject to different pubertal and gender influences. We conclude that gonadal regulation of the HPA axis develops via distinct mechanisms in males and females. Puberty-related shifts in parvocellular neurosecretory function in males are emphasized by stress-induced shifts in neuronal activation, whereas biosynthetic alterations dominate in female rats.

Penile Weight and Cell Subtype Specific Changes in a Post-Radical Prostatectomy Model of Erectile Dysfunction

We evaluated neurogenic erectile dysfunction, focusing on the post-radical prostatectomy model. We investigated changes in DNA, protein and apoptotic cells of the rat penis after denervation. Gross morphometry was measured to elucidate the impact of chemical changes. Postpubertal male Sprague-Dawley rats were randomized to bilateral or unilateral cavernous nerve transection, or sham operation. Wet weight, DNA content and protein content were measured. Tissue sections were stained for apoptosis by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling and the apoptotic index was calculated. Dual staining was performed for endothelial and smooth muscle cells to identify apoptotic cells. Penile wet weight was significantly decreased at all time points after bilateral neurotomy (p <0.0005). Unilateral neurotomy allowed much greater preservation of penile weight. DNA content was significantly decreased in bilaterally denervated penes and unchanged in unilaterally operated penes. Protein content was not significantly altered in the bilateral or unilateral cohorts. Bilateral neurotomy induced significant apoptosis, while unilateral surgery caused significantly less apoptosis. Each population had apoptotic clustering just beneath the tunica albuginea, which was mostly smooth muscle cells. These data suggest the importance of neural integrity to maintain penile homeostasis. The loss in penile weight was consistent with the anecdotal experience of many clinicians. Decreased DNA content may have been due to significant levels of apoptosis in smooth muscle cells. Preserved protein content may suggest an increase in extracellular protein, as postulated in corporeal fibrosis. The subtunical population of apoptotic smooth muscle cells revealed a mechanism for veno-occlusive dysfunction observed after radical prostatectomy. These effects were significantly moderated in the unilateral model, reinforcing the critical nature of neural integrity.

Influence of dietary zinc deficiency during development on hepatic CYP2C11, CYP2C12, CYP3A2, CYP3A9, and CYP3A18 expression in postpubertal male rats

The present study investigated the effect of dietary zinc deficiency during the developmental period on hepatic cytochrome P450 (CYP) expression in postpubertal male rats. Twenty-one-day-old weanling male Wistar rats were randomly assigned to one of the following dietary groups: zinc-adequate (31 mg zinc/kg diet); marginal zinc-deficient (3 mg zinc/kg diet); severe zinc-deficient (1 mg zinc/kg diet); or pair-fed control for either the marginal or severe zinc-deficient group. All rats were killed at 63 days of age. Compared with the corresponding pair-fed controls, marginal zinc deficiency decreased CYP2C11-mediated testosterone 2α- and 16α-hydroxylase activities by 43 and 42%, respectively, whereas severe zinc deficiency reduced each of these activities by approximately 60%. The decrease in CYP2C11 activity was accompanied by a reduction in CYP2C11 protein and mRNA levels, as assessed by immunoblot and reverse transcription-polymerase chain reaction (RT-PCR) assays, respectively. Additional RT-PCR analysis indicated that severe zinc deficiency decreased CYP3A2 and CYP3A18 mRNA levels by 49 and 43%, respectively, whereas it increased CYP2C12 (253%) and CYP3A9 (238%) mRNA expression. Plasma testosterone concentration was decreased by 67% in the marginal zinc-deficient group when compared with the corresponding pair-fed control group. By comparison, it was below the limit of quantification (0.2 ng/mL) in the severe zinc-deficient rats. Overall, these results indicate that dietary zinc deficiency during the developmental period feminized the hepatic gene expression of the sexually dimorphic CYP2C11, CYP3A2, CYP3A18, CYP2C12, and CYP3A9 in postpubertal male rats.