Castration Research Articles

Sulfur dioxide (SO2) donors, a new gasotransmitter, improve erectile dysfunction after castration in a rat model.

Androgen deprivation is associated with erectile dysfunction (ED). In different animal models, sulfur dioxide (SO2) donors Na2SO3 and NaHSO3 reduced oxidative stress, fibrosis, and inflammation which contribute to the pathogenesis of androgen deprivation-induced ED, however the effect of SO2 donors on ED in castrated rats were not known. To investigate the therapeutic effect of SO2 donors, Na2SO3/NaHSO3, on ED in castrated rat model. Sprague-Dawley male rats (n=30) were divided into four groups; control, control-treated with Na2SO3/NaHSO3, castrated, and castrated-treated with Na2SO3/NaHSO3. Castration was induced by bilateral scrotal incisions. Four weeks after castration, rats were treated with Na2SO3/NaHSO3 (0.54/0.18mmol/kg) intraperitoneally (i.p.) for 4 weeks. Intracavernosal pressure/mean arterial pressure ratio (ICP/MAP) and total ICP were measured to evaluate in vivo erectile responses in cavernosal tissue. In vitro relaxant and contractile responses were measured in all groups. Endothelial nitric oxide synthase (eNOS), neuronal NOS (nNOS), PI3 kinase p85 alpha + gamma (PI3K), protein kinase B (AKT 1/2/3), cysteine dioxygenase-1 (CDO), and aspartate aminotransferase (AAT) expressions and localizations were evaluated by Western blotting and immunohistochemical staining. The smooth muscle/collagen ratio was evaluated by Masson's trichrome staining. Prostate (p<0.001) and penis weight (p<0.001), total serum testosterone (T) level (p<0.001), and in vivo erectile responses (p<0.001 at 7.5 and 5V, p<0.05 at 2.5V for ICP/MAP and total ICP) of castrated rats were decreased compared with control. SO2 donors improved reduced ICP/MAP ratio and total ICP (p<0.01 at 7.5, 5, and 2.5V for ICP/MAP and total ICP) nitrergic (p<0.05 at 20Hz), and endothelium-independent relaxation (p<0.05 at 1nM, p<0.01 at 10µM and 100µM) in the castrated group. Decreased eNOS (p<0.01) and AKT (p<0.001) protein expressions in the castrated group were normalized by SO2. SO2 donors partially restored the reduced smooth muscle/collagen ratio in the castrated group (p<0.001). The expressions and locations of nNOS, PI3K, CDO, and AAT proteins in penile tissue did not alter among all groups (p>0.05). SO2 donors significantly improve erectile functions and relaxation responses in a castrated rats via ameliorating endothelial damage and fibrosis. Androgen deprivation inhibits the AKT/eNOS signaling while SO2 activates this pathway. SO2 donors may be promising for the treatment of ED in hypoandrogenic men.

Benchmarking cross-species single-cell RNA-seq data integration methods: towards a cell type tree of life.

Cross-species single-cell RNA-seq data hold immense potential for unraveling cell type evolution and transferring knowledge between well-explored and less-studied species. However, challenges arise from interspecific genetic variation, batch effects stemming from experimental discrepancies and inherent individual biological differences. Here, we benchmarked nine data-integration methods across 20 species, encompassing 4.7 million cells, spanning eight phyla and the entire animal taxonomic hierarchy. Our evaluation reveals notable differences between the methods in removing batch effects and preserving biological variance across taxonomic distances. Methods that effectively leverage gene sequence information capture underlying biological variances, while generative model-based approaches excel in batch effect removal. SATURN demonstrates robust performance across diverse taxonomic levels, from cross-genus to cross-phylum, emphasizing its versatility. SAMap excels in integrating species beyond the cross-family level, especially for atlas-level cross-species integration, while scGen shines within or below the cross-class hierarchy. As a result, our analysis offers recommendations and guidelines for selecting suitable integration methods, enhancing cross-species single-cell RNA-seq analyses and advancing algorithm development.

Comprehensive analysis of the C. elegans connectome reveals novel circuits and functions of previously unstudied neurons.

Despite decades of research on the Caenorhabditis elegans nervous system based on an anatomical description of synaptic connectivity, the circuits underlying behavior remain incompletely described and the functions of many neurons are still unknown. Updated and more complete chemical and gap junction connectomes of both adult sexes covering the entire animal including the muscle end organ have become available recently. Here, these are analyzed to gain insight into the overall structure of the connectivity network and to suggest functions of individual neuron classes. Modularity analysis divides the connectome graph into 10 communities that can be correlated with broad categories of behavior. A significant role of the body wall musculature end organ is emphasized as both a site of significant information convergence and as a source of sensory input in a feedback loop. Convergence of pathways for multisensory integration occurs throughout the network-most interneurons have similar indegrees and outdegrees and hence disperse information as much as they aggregate it. New insights include description of a set of high degree interneurons connected by many gap junctions running through the ventral cord that may represent a previously unrecognized locus of information processing. There is an apparent mechanosensory and proprioceptive field covering the entire body formed by connectivity of the many mechanosensory neurons of multiple types to 2 interneurons with output connections across the nervous system. Several additional significant, previously unrecognized circuits and pathways are uncovered, some involving unstudied neurons. The insights are valuable for guiding theoretical investigation of network properties as well as experimental studies of the functions of individual neurons, groups of neurons, and circuits.

Determination of the Effects of Aminoethoxyvinilglycine (AVG) and Gibberellic Acid (GA3) Applications on Pre-Harvest Fruit Drop Amount and Fruit Quality in Hakko Pear Cultivar

This study was conducted to determine the effects of pre-harvest Aminoethoxyvinylgylcine (AVG) and Gibberellic acid (GA3) applications on the pre-harvest fruit drop amount and fruit quality in the 'Hakko' pear (Pyrus pyrifolia) cultivar grafted on BA29 rootstock in a private orchard in the Bala district of Ankara in 2021-2022. It was conducted in an orchard belonging to a producer. 50-100-150 mg/l AVG and 25-50-75 mg/l GA3 were applied 4 weeks before the estimated harvest date. Fruits are harvested at full maturity date; Pomological properties including cumulative drop percentage, yield per tree, fruit weight, fruit width and length, fruit stem width and length, fruit firmness, fruit color, as well as chemical properties such as soluble solid content (SSC), pH and titratable acidity (TA) were evaluated. It was observed that all doses of AVG and GA3 during the harvest period reduced the cumulative drop rate compared to the control application (6.78%). In general, the yield per tree was found to be high in GA3 applications. Both AVG and GA3 applications had statistically significant effects on fruit weight, fruit width and length, fruit flesh firmness, SSC, and pH. It was observed that both AVG and GA3 applications reduced pre-harvest fruit drop and improved fruit quality characteristics compared to the control.

Mesopredator release moderates trophic control of plant biomass in a Georgia salt marsh.

Predators regulate communities through top-down control in many ecosystems. Because most studies of top-down control last less than a year and focus on only a subset of the community, they may miss predator effects that manifest at longer timescales or across whole food webs. In southeastern US salt marshes, short-term and small-scale experiments indicate that nektonic predators (e.g., blue crab, fish, terrapins) facilitate the foundational grass, Spartina alterniflora, by consuming herbivorous snails and crabs. To test both how nekton affect marsh processes when the entire animal community is present, and how prior results scale over time, we conducted a 3-year nekton exclusion experiment in a Georgia salt marsh using replicated 19.6 m2 plots. Our nekton exclusions increased densities of plant-grazing snails and juvenile deposit-feeding fiddler crab and, in Year 2, reduced predation on tethered juvenile snails, indicating that nektonic predators control these key macroinvertebrates. However, in Year 3, densities of mesopredatory benthic mud crabs increased threefold in nekton exclusions, erasing the tethered snails' predation refuge. Nekton exclusion had no effect on Spartina biomass, likely because the observed mesopredator release suppressed grazing snail densities and elevated densities of fiddler crabs, whose burrowing alleviates soil stresses. Structural equation modeling supported the hypotheses that nektonic predators and mesopredators control invertebrate communities, with nektonic predators having stronger total effects on Spartina than mud crabs by controlling densities of species that both suppress (grazers) and facilitate (fiddler crabs) plant growth. These findings highlight that salt marshes can be resilient to multiyear reductions in nektonic predators if mesopredators are present and that multiple pathways of trophic control manifest in different ways over time to mediate community dynamics. These results highlight that larger scale and longer-term experiments can illuminate community dynamics not previously understood, even in well-studied ecosystems such as salt marshes.

Making Neurobots and Chimerical Ctenophores.

Making living machines using biological materials (cells, tissues, and organs) is one of the challenges in developmental biology and modern biomedicine. Constraints in regeneration potential and immune self-defense mechanisms limit the progress in the field. Here, we present unanticipated features related to self-recognition and ancestral neuro-immune architectures of new emerging reference species - ctenophores or comb jellies. These are descendants of the earliest survival metazoan lineage with unique tissues, organs and independent origins of major animal traits such as neurons, muscles, mesoderm, and through-gut. Thus, ctenophores convergently evolved complex organization, compared to bilaterians. Nevertheless, their neural and immune systems are likely functionally coupled, enabling designs and experimental construction of hybrid neural systems and even entire animals. This report illustrates impressive opportunities to build both chimeric animals and neurobots using ctenophores as models for bioengineering. The obtained neurobots and chimeric animals from three ctenophore species (Bolinopsis, Mnemiopsis, and Pleurobrachia) were able to be autonomous and survive for days. In sum, the unification of biodiversity, cell biology, and neuroscience opens unprecedented opportunities for experimental synthetic biology.

Distribution and Antimicrobial Susceptibility Profile of Extended Spectrum Beta-Lactamase Producing-Escherichia coli from Ruminants in Maiduguri, Nigeria: Public Health Implications

Extended spectrum beta-lactamase (ESBL) producing Escherichia coli (E. coli) is resistant to many antibiotics, including cephalosporins and penicillin. The emergence of ESBL-E. coli poses a threat to the entire animal and human community, not just individuals with direct exposure to ruminants but also to the environment. The study evaluated the isolation rate and antimicrobial susceptibility profile of ESBL-producing E. coli from 128 ruminants in the University of Maiduguri campus. E. coli was isolated from 32 (25%) of the rectal swabs collected from cattle, goats, and sheep. ESBL-producing E. coli was more common in young animals 8(30.8%) than in adult animals 12 (11.8%). More than 80% of the isolates were resistant to all of the beta-lactam antibiotics used in the study. The study suggests that the high prevalence of ESBL-producing E. coli in ruminants may be associated with the unregulated use of beta-lactam antibiotics in veterinary practice and animal husbandry. We recommend public health awareness about the dangers of antimicrobial resistance. Also, continued monitoring of BL-E. coli prevalence in both animals and humans is crucial to track trends and guide interventions. Promoting the judicious use of antibiotics in both human and veterinary medicine is essential to reduce selective pressure for resistance development. Improved hygiene practices at farms, slaughterhouses, and food processing facilities can minimize contamination and human exposure.

Investigation of Pharmacological Screening Techniques for Diabetes Mellitus

Diabetes is the medical term for a condition in which the body fails to generate or use insulin as intended, leading to high blood sugar levels. Both in-vitro and in-vivo techniques are employed to assess the antidiabetic potential of synthetic or natural compounds that have been extracted from conventional plants. The rat paw oedema method is frequently used to screen anti-inflammatory medications. The use of animals in this procedure has drawbacks related to ethical concerns. We proposed an in vitro system in this context that would not have these drawbacks. Rat in vivo experiments are frequently used to screen anti-hyperlipidemic medications. Pharmacological screening currently entails testing novel chemical entities as plant extracts or any other type of material (synthetic or semisynthetic) in isolated preparations before testing on entire animals. Rats and mice are typically used, but occasionally higher animals like dogs and monkeys are as well. These techniques have been used to assess the majority of medications now used in therapy. Wherever possible, non-animal alternatives are being developed. Pharmacologists' constant struggle is to reconcile in vitro and in vivo results. A thorough grasp of the in vivo performance is one of the main objectives of pharmacological screening. Therefore, it would be praiseworthy to establish in vitro assessments that might be connected to in vivo performance.

A versatile steel belt casting equipment for in situ synchrotron radiation x-ray scattering measurement of polymer films.

A steel belt casting equipment, weighing approximately ∼6-7 tons and measuring ∼5m in length, has been designed and developed for simulating the industrial processing of polymer films and being combined with synchrotron radiation in situ x-ray scattering measurements. Through modification of its modules, it is feasible to implement two distinct film casting modes, namely the wet and the dry casting processes. The speed of a steel belt can span from 0.5 to 8 m/min. The highest experimental temperature and drying wind speed are 300 °C and 6m/s, respectively. All film casting parameters, such as extrusion speed, distance between die and steel belt, casting speed, temperature, and wind speed, can be adjusted independently. Especially, the control accuracy of the temperature and casting rate can reach ±0.1 °C and ±0.01 m/min, respectively. The feasibility of this equipment has been validated through in situ x-ray scattering tests at the BL10U1 industrial beamline of the Shanghai synchrotron radiation facility. With the assistance of this equipment, the understanding of the physical mechanism behind the film casting process should be improved so that the development of advanced functional polymer films.

Abstract P355: Multiomic Analyses Reveal Sex-specific Mechanisms Governing Cardiac Fibrosis.

Cardiac fibrosis—the deposition of excess extracellular matrix in the heart—occurs during pathological cardiac remodelling and precedes cardiac dysfunction and heart failure. Experimental and clinical data show that both cardiac fibrosis and heart failure exhibit sex-specific differences, particularly in the absence of ischemic injury. However, no study to date has systematically examined this, or the hormonal mechanisms driving these differences, using high-resolution single-cell and spatial omics. To address this gap, we applied single-cell and spatial omics to map the quality and distribution of non-ischemic cardiac fibrosis in human and mouse hearts. Further, to query the impact of sex hormones on cardiac fibrosis development, we analysed hearts of castrated (CAST) and ovariectomized (OVX) mice, which were ectopically infused with angiotensin-II (AngII). Using single cell transcriptomic data of hypertensive mouse hearts, we identified a fibroblast population driving cardiac fibrosis with a unique gene signature. We confirmed the presence of these cells in multiple mouse models and aged donor human hearts. Spatial mapping of fibrosis showed a sex-specific distribution of fibrosis, specifically in the development of perivascular fibrosis in the heart. Hypertensive male mice exhibited extensive perivascular fibrosis, and coronary artery adventitial hypertrophy, which was absent in females. However, OVX resulted in the development of perivascular fibrosis in hypertensive mice suggesting a cardioprotective role of estrogen. Confirming these observations, spatial transcriptomic analyses showed distinct fibrotic signatures driving perivascular and interstitial fibrosis, and transcriptomic differences between females and males. Our findings provide fundamental new insights towards the importance of biological sex in driving cardiac fibrosis, pointing to new mechanisms that may be manipulated to ameliorate development of heart failure.

Evaluation of the application and effects of intratesticular use of vaseline and acetylsalicylic acid 30% + vaseline for chemical castration in male rats

Evaluation of the application and effects of intratesticular use of vaseline and acetylsalicylic acid 30% + vaseline for chemical castration in male rats

Prostate-specific antigen, androgen, progesterone and oestrogen receptors in Benign prostatic hyperplasia: human tissues and animal model study

Background Direct evidence for the relationship between a large prostate (≥80 ml) and androgen receptor/PSA signal remains lacking in benign prostatic hyperplasia (BPH). Our aim is to identify whether the cause of a large prostate is related to progesterone receptor (PGR) androgen receptor (AR), oestrogen receptor α, β (ERα,β) and prostate-specific antigen (PSA). Materials and methods Surgical specimens of BPH in plasmakinetic resection of the prostate (PKRP) with three groups of different prostate-sizes with mean volumes of 25.97 ml, 63.80 ml, and 122.37 ml were collected for immunohistochemical analysis of the tissue microarray with PGR, AR, PSA and ERs. Rats were castrated and treated with testosterone replacement to explore androgen and PGR, AR and ERs expression levels in the prostate. Quantitative real-time reverse transcription polymerase chain reaction (Rt-PCR) for mRNA detection of above genes was conducted. Results Immunoblotting, Rt-PCR and immunohistochemistry assays showed that PGR, PSA, AR, ERα expression levels were positively correlated with prostate size and that ERβ expression levels were negatively correlated with prostate volume. Animal experiments have shown that prostate volume is decreased in castrated rats with decreased PGR, AR, ERα and increased ERβ expression levels. Conclusion PGR, AR, ERs signals can be regarded as important factors for large-sized prostates in BPH patients (≥100 ml).

Zhuangyao Jianshen pill ameliorates testosterone-induced benign postatic hyperplasia in rats.

To determine the therapeutic effects of the Zhuangyao Jianshen pill (, ZYJSP) against benign prostatic hyperplasia (BPH) and investigate the underlying mechanism. Forty-eight male Sprague-Dawley rats were randomly divided into six groups: Control group, BPH model group, finasteride-treated group, ZYJSP low, medium and high dose groups. Except for the control group, 40 rats were castrated and injected with testosterone propionate (TP) for 28 consecutive day to induce BPH. Meanwhile, the corresponding drugs were administered by gavage. The prostate wet weight, prostate index (PI), and the histopathological changes in the prostate were measured as the basis for examining the efficacy of ZYJSP against BPH. Levels of the serum sex hormones, oxidative stress markers, inflammatory markers, renal function markers, growth factors, and Cyclin D1 expression in prostate were measured to characterize the therapeutic mechanism of ZYJSP against BPH. ZYJSP administration significantly reduced prostate wet weight and PI and ameliorated histological changes of the prostate in TP-treated castrated rats. TP markedly increased the levels of creatinine, blood urea nitrogen and growth factors in the serum as well as the expression of the Cyclin D1 in the prostate. Most of these markers were significantly decreased by ZYJSP. ZYJSP significantly restored the dysregulation of testosterone, estradiol, and dihydrotestosterone caused by TP. Furthermore, ZYJSP relieved TP-induced prostate injury and exhibited both anti-inflammatory and anti-oxidant activity by decreasing interleukin-6, interleukin-8, and malondialdehyde levels and increasing the activity of superoxide dismutase in the serum. These findings indicate that ZYJSP can effectively ameliorate BPH induced by TP in castrated rats, and the underlying mechanism might be related to regulating sex hormone balance, reducing oxidative stress, and inhibiting the inflammatory response.

Androgenic effects of the aqueous extract of Pycnanthus angolensis (Welw.) Warb. (Myristicaceae) wood in hemicastrated male Wistar rats

Background: Androgen deficiency is the most common disorder of reproductive function and can lead to male sexual disorders. Objective: This study was designed to evaluate the androgenic effects of Pycnanthus angolensis (Welw.) Warb in hemicastrated rats. Materials and methods: Forty-two male rats were divided into 6 groups of 7 rats each, including a group of uncastrated rats that received distilled water (10 ml/kg); a group of castrated rats that received 10 ml/kg of distilled water; a group of castrated rats that received testosterone enanthate (3 mg/kg BW) per week intramuscularly; and 3 groups of castrated rats that received 43, 86 and 172 mg/kg of the aqueous extract of Pycnanthus angolensis, respectively. After 14 days of oral treatment, the rats were killed by decapitation. The blood was collected and the androgen-dependent organs were collected for histological sectioning, and biochemical analysis. The tail of the epididymis was used to assess sperm quality. Results: Treatment with the aqueous extract at doses of 43 and 86 mg/kg, significantly improved the sexual behavior of castrated rats, with increases of 25.92% and 22.74% intromissions frequency, and 67.06% and 56.46% mount frequency, compared to those in the castrated rats which did not receive any treatment. The extract also enhanced sperm quality in castrated rats. Both doses also significantly increased serum testosterone levels with rates of 45.07% and 49.00%, respectively; compared to those in the negative control group. Conclusion: In view of the aforesaid results, Pycnanthus angolensis (Welw.) Warb could be considered as a promising natural agent in hypogonadism management. Keywords: Androgen, hypogonadism, castrated male rats, unilateral castration, Pycnanthus angolensis (Welw.) Warb

Computational Investigation of the Influencing Parameters on the Solidification of Thermoplastic Beryllium Oxide Slurry in a Cylindrical Shell

This article presents a computational study of the influencing parameters on the solidification of the thermoplastic beryllium oxide slurry in an annular forming cavity. The main purpose of this paper is to study the effect of cooling and casting conditions on the solidification of the BeO suspension by considering the temperature-dependent rheological and physical properties. The results of calculations of the Bingham–Papanastasiou rheological model with experimental data in the intervals of phase transitions with different casting rates of beryllium ceramics have been validated. The use of the regularization parameter made it possible to approximate the flow of the slurry at all levels of its shear rates as highly viscous, followed by a continuous transition to a solid state. The speed of heat removal from the molding during the solidification period is determined by the speed of movement of the slurry and the temperature field on which the width of the transition region depends. The process of solidification of the slurry mass has been evaluated by changing its heat flow distribution and density along the length of the concentric channel. The obtained model calculation results make it possible to control the casting process and eventually realize a uniform structure of castings.

Sex Differences in Dopamine Release in Nucleus Accumbens and Dorsal Striatum Determined by Chronic Fast-Scan Cyclic Voltammetry: Effects of Social Housing and Repeated Stimulation.

We investigated sex differences in dopamine (DA) release in the nucleus accumbens (NAc) and dorsolateral striatum (DLS) using a chronic 16-channel carbon fiber electrode and fast-scan cyclic voltammetry (FSCV). Electrical stimulation-induced (ES; 60 Hz) DA release was recorded in the NAc of single- or pair-housed male and female rats. When core (NAcC) and shell (NAcS) were recorded simultaneously, there was greater ES DA release in NAcC of pair-housed females compared with single females and males. Housing did not affect ES NAc DA release in males. In contrast, there was significantly more ES DA release from the DLS of female rats than male rats. This was true prior to and after treatment with methamphetamine. Furthermore, in castrated (CAST) males and ovariectomized (OVX) females, there were no sex differences in ES DA release from the DLS, demonstrating the hormone dependence of this sex difference. However, in the DLS of both intact and gonadectomized rats, DA reuptake was slower in females than that in males. Finally, DA release following ES of the medial forebrain bundle at 60 Hz was studied over 4 weeks. ES DA release increased over time for both CAST males and OVX females, demonstrating sensitization. Using this novel 16-channel chronic FSCV electrode, we found sex differences in the effects of social housing in the NAcS, sex differences in DA release from intact rats in DLS, and sex differences in DA reuptake in DLS of intake and gonadectomized rats, and we report sensitization of ES-induced DA release in DLS in vivo.

A low androgenic state inhibits erectile function by suppressing endothelial glycosides in the penile cavernous tissue of rats.

The endothelial glycocalyx is an important barrier that protects the structure and function of endothelial cells. Androgen deficiency is a common factor that causes structural and functional impairment of endothelial cells. To investigate changes in the endothelial glycocalyx in the penile corpus cavernosum of the rat with low androgen status and its relationship with erection function. Eighteen 10-week-old Sprague-Dawley male rats were randomly divided into 3 groups (n = 6 each): sham operation, castration, and castration + testosterone replacement. The maximum intracavernosal pressure/mean arterial pressure of the penis was measured after modeling for 4weeks. The expression levels of endothelial nitric oxide synthase (eNOS), phospho-eNOS, syndecan 1, heparanase, and nitric oxide in penile cavernous tissue and the serum levels of heparan sulfate, hyaluronic acid, tumor necrosis factor α, and interleukin 6 were determined. Transmission electron microscopy was used to observe the ultrastructure of the endothelial glycocalyx in penile tissue. The thickness of the endothelial glycocalyx in the penile corpus cavernosum of castrated rats was significantly lower than that of the control group. In the castrated rats, the endothelial glycocalyx thickness, syndecan 1 level, ratio of phospho-eNOS to eNOS, nitric oxide level, and maximum intracavernosal pressure/mean arterial pressure (3V, 5V) were significantly lower than those in the sham group (P < .05). The expression of heparanase and the serum levels of tumor necrosis factor α and interleukin 6 were significantly higher in the castrated group than in the sham group (P < .05). Upregulating the expression of the endothelial glycocalyx in the penile corpus cavernosum may be a new method for treating erectile dysfunction caused by low androgen levels. This study confirms that low androgen status promotes the breakdown of the endothelial glycocalyx. However, further research is needed to determine whether androgens are related to the synthesis of the endothelial glycocalyx. Low androgen status may suppress the level of nitric oxide in the cavernous tissue of the penis via impairment of the endothelial glycocalyx, resulting in inhibited erection function in rats.

Spaycations: A Qualitative Study of Veterinarians’ Motivations And Perceived Impacts of Remote Volunteer Spay Neuter

Increasingly, veterinarians skilled in High Quality High Volume Spay Neuter (HQHVSN) are invited to volunteer their surgical services in distant low-resource communities on trips that have become casually known as “spaycations.” While these trips are numerous, there is little research on veterinarians’ motivations for participating and their perceptions of the impacts these clinics have on communities they visit. The current study was open to veterinarians who work in or are trained in HQHVSN whether or not they had been on a spaycation trip. For the purpose of this study, a spaycation is defined as an unpaid or minimally paid trip from a high resource area to a low or moderate resource country or area to provide spay neuter services that is organized by someone other than the individual surgeon. Forty-one veterinarians responded to an electronic questionnaire containing open-ended questions relating to their thoughts and experiences regarding spaycations and their impacts on the volunteer veterinarians as well as on the animals, clients, communities, veterinary practitioners, and animal populations in the areas visited. A reflexive thematic analysis was conducted in which the veterinarians’ responses were coded inductively for semantic themes using a critical realist approach. Respondents had participated in a variety of spaycations around the world over the past 20 years. Most responding veterinarians were motivated by a desire to make a difference and give back to communities in need as well as the desire to travel and to experience other cultures. Many enjoyed bonding with and learning from other vets and team members on the spaycation, and said that while the trips were exhausting they were also paradoxically energizing, and that they renewed their professional passion. Many veterinarians were concerned by the financial and time commitments associated with participating in spaycations, and these costs had prevented some veterinarians from participating. Further reasons for not participating in spaycations included concerns about stress and burnout and about the continual expectation for veterinarians to volunteer their time. Some veterinarians presented concerns about spaycations producing damaging interactions with the local communities including cultural misunderstandings, distrust, the creation of dependence, colonialism, and White Savior syndrome. Local involvement in the spay neuter event varied, with some events entirely planned and staffed locally and involving training and mentorship of local veterinary professionals and students, while other spaycations included little local involvement. Veterinarians varied in their estimation of the animal population impact of the spaycation and agreed that recurrent or ongoing interventions are necessary for appreciable and sustainable population impacts, but that health impacts on individual animals and their families were important and visible even after a single trip. Thematic analysis identified three main themes, HQHVSN is a special skill set, Colonialism and Cost and Value. Spaycations are a unique way for HQHVSN veterinarians to use their distinctive skills in communities of need. The compelling nature of these trips necessitates conscientious and culturally-sensitive leadership and planning to provide safe, sustainable, community-centered programs with a focus on long-term solutions.

An assessment of the (anti)androgenic properties of hexachloronaphthalene (HxCN) in male rats

The persistent organic pollutants (POPs) defined by the Stockholm Convention include polychlorinated naphthalenes (PCNs); of these, the most toxic, persistent, abundant, dioxin-like congeners found in human tissues are the hexachloronaphthalenes (HxCNs). Recent research also indicates that PCNs may disrupt hormonal homeostasis. The aim of this study was to evaluate the (anti)androgenic action of HxCN. Immature, castrated male Wistar rats were exposed per os to HxCN in corn oil at daily doses ranging from 0.3 to 3.0 mg kg−1 for 10 days. According to the OECD 441 protocol (Hershberger Bioassay), the anti-androgenic assay groups were co-exposed with testosterone propionate (TP), while the androgenic groups were not. TP was used as the reference androgen (subcutaneous daily doses of 0.4 mg kg−1), and flutamide (FLU) as the reference antiandrogen (per os daily doses of 3.0 mg kg−1). Five assessory sex tissues (ASTs) were weighed: ventral prostate, seminal vesicles, levator ani-bulbocavernosus muscle (LABC), Cowper's glands and glans penis. HxCN + TP significantly decreased the weight of the ventral prostate and seminal vesicle indicating an anti-androgenic action via 5α-reductase inhibition. These weight changes were also accompanied by abnormalities in cell morphology and hormonal disturbances: lowered levels of the testosterone and thyroid hormones thyroxine and triiodothyronine. Disturbances were also noted in the lipid profile, viz. total cholesterol, triglycerides and high-density lipoprotein and non-HDL fraction content. However, the direction of these changes differed depending on the size of the HxCN dose. No dose-effect relationship was noted for most of the obtained results; as such, exposure to even small HxCN doses run the risk of anti-androgenic effects in the general population, especially when encountered in combination with other POPs and endocrine-disrupting chemicals in the environment.

Effects of Cross-Sex Hormone Therapy on Metabolic Parameters and Aortic Relaxation in Castrated Male Rats

With the rising awareness, the number of individuals identifying themselves as transgender in the US is increasing over the years. Cross-sex hormone therapy (CSHT) may alter numerous cardiometabolic parameters leading to the increased risk of cardiovascular diseases (CVD) in transgender population. Epidemiological studies suggest that transgender females (male to female, MtF) on estrogen therapy develop higher risk of CVD compared to transgender males (female to male, FtM) taking testosterone. Underlying mechanisms of impaired cardiovascular functions in MtF are not well documented. This study was undertaken to examine the effects of 17β-estradiol (E2) on certain cardiometabolic parameters and aortic reactivity in castrated (CAS) male Sprague Dawley (SD) rats. The 8-10-weeks old CAS rats were subcutaneously implanted with either 1.5 mg of E2 (CAS+E2) or placebo (CAS+PL) containing pellets for ~35 days. The age-matched SD intact male (IM) rats were also included in the experimental groups. After performing the glucose tolerance test, animals were sacrificed, and the blood was collected for later measurements of the HbA1C and triglyceride (TG) levels. Endothelium-dependent vasorelaxation (EDV) to acetylcholine (ACh) in aortic rings pre-contracted with phenylephrine (PE) was measured before and after treatment with indomethacin (a cyclooxygenase inhibitor), followed by L-NAME [a nonselective nitric oxide (NO) synthase (NOS) inhibitor]. Contractile responses to PE before and after L-NAME in aortic rings and sodium nitroprusside (SNP)-induced relaxation responses in endothelium-denuded rings were also measured. Here, we report the decreased body weight and visceral white adipose tissue, and improved HbA1C and glucose tolerance in E2-treated CAS rats. However, the E2-treated CAS rats exhibited elevated plasma level of TG. Furthermore, the vascular relaxation to ACh was significantly impaired in aortas from this group compared to those in CAS+PL and IM rats. The impairment of ACh responses in CAS+E2 rats was accompanied by a significant decrease in NO contribution to ACh vasorelaxation. The basal NO levels and the smooth muscle sensitivity to NO were not altered, whereas the maximum contractile responses to PE were enhanced in aortas of CAS+E2 group compared to IM. In conclusion, our data suggests that the glucose homeostasis was improved in CAS+E2 rats. Regardless, this group exhibited increased level of TG in plasma and decreased aortic vasorelaxation to ACh. The impairment of EDV in E2-treated CAS rats might be due to reduced NO-mediated vasorelaxation or increased contractile responses observed in this group. Additional studies are needed to document the underlying mechanisms for improvement of glucose homeostasis and impairment of EDV in CAS+E2 rats. NIDA/NIGMS, 1SC1DA052120-01 to MF and Bridge Grant from University of the Pacific to RR. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.