Reproductive Physiology Research Articles

Deletion of Androgen Receptor in LepRb Cells Improves Estrous Cycles in Prenatally Androgenized Mice.

Androgens are steroid hormones crucial for sexual differentiation of the brain and reproductive function. In excess, however, androgens may decrease fertility as observed in polycystic ovary syndrome, a common endocrine disorder characterized by oligo/anovulation and/or polycystic ovaries. Hyperandrogenism may also disrupt energy homeostasis, inducing higher central adiposity, insulin resistance, and glucose intolerance, which may exacerbate reproductive dysfunction. Androgens bind to androgen receptors (ARs), which are expressed in many reproductive and metabolic tissues, including brain sites that regulate the hypothalamo-pituitary-gonadal axis and energy homeostasis. The neuronal populations affected by androgen excess, however, have not been defined. We and others have shown that, in mice, AR is highly expressed in leptin receptor (LepRb) neurons, particularly in the arcuate (ARH) and the ventral premammillary nuclei (PMv). Here, we assessed if LepRb neurons, which are critical in the central regulation of energy homeostasis and exert permissive actions on puberty and fertility, have a role in the pathogenesis of female hyperandrogenism. Prenatally androgenized (PNA) mice lacking AR in LepRb cells (LepRbΔAR) show no changes in body mass, body composition, glucose homeostasis, or sexual maturation. They do show, however, a remarkable improvement of estrous cycles combined with normalization of ovary morphology compared to PNA controls. Our findings indicate that the prenatal androgenization effects on adult reproductive physiology (ie, anestrus and anovulation) are mediated by a subpopulation of LepRb neurons directly sensitive to androgens. They also suggest that the effects of hyperandrogenism on sexual maturation and reproductive function in adult females are controlled by distinct neural circuits.

Chronic periadolescent leuprolide exposure affects the development of reproductive physiology and behavior of female and male rats differently, but both mature after treatment termination

BackgroundGnRH agonists have been used to halt the development of puberty in children with precocious puberty since the 1980s. Recently, drugs like Lupron Depot® (leuprolide acetate), have been used to suppress pubertal progression in adolescents who are questioning their gender identity. However, few preclinical studies have been conducted to investigate potential effects of using GnRH agonists in this context.MethodsThe present study tested the effects of daily leuprolide treatment (50 µg/kg, postnatal day (PD) 25–50) on pubertal onset in female (i.e., vaginal opening) and male (i.e., preputial separation) Long-Evans rats. The first estrous cycle immediately after vaginal opening was also measured. Sexual behavior and sexual motivation were tested using the partner-preference paradigm. Female rats were tested during the first behavioral estrus after treatment ended (between PD 51–64). Male rats were tested weekly for four consecutive weeks starting three days after treatment ended (PD 53).ResultsConsistent with previous findings, leuprolide significantly delayed pubertal onset in both female and male rats. In addition, the first estrous cycle during the treatment period was disrupted by leuprolide, as indicated by a failure to cycle into estrus after vaginal opening until treatment ended. However, leuprolide affected neither sexual motivation nor fertility when female rats were tested within 14 days of leuprolide treatment ending. In contrast, the development of copulatory behavior and sexual motivation was significantly delayed by leuprolide in male rats; however, mature reproductive behavior was observed by the fourth week post-treatment.ConclusionsTaken together with previous findings, the present results indicate that male rats may be more sensitive to periadolescent leuprolide administration, taking longer to overcome the effects of leuprolide than female rats. Nevertheless, not long after leuprolide treatment is discontinued, sex-typical reproductive physiology and behavior emerge fully in female and male rats, indicating that the drug’s effects are not permanent. If translatable to humans, leuprolide may be a reversible option to give adolescents more time to consider their gender identity with minimal long-term effects on sexual development.

Diapause in <i>Chilo partellus</i>: A Research Journey

Spotted stem borer, Chilo partellus (Swinhoe) is one of the most widely distributed pests of coarse cereals, causing 18 to 25% yield losses in Asia and Africa. The larvae of C. partellus pass through hibernation under North Indian and aestivation under South Indian conditions. Although diapause helps C. partellus in adapting under unfavorable conditions, there is 17.2 to 28.3% and 7.0 to 33.7% population sacrifice during hibernation and aestivation, respectively. The population heterogeneity in C. partellus could be due to hibernation or aestivation, wherein the models, Ikemoto & Takai (linear), and Lactin-1 and Lactin-2 (non-linear) are efficient for describing temperature dependent development and estimating the temperature thresholds of diapausing larvae. This helps in predicting the occurrence, seasonal emergence, number of generations and population dynamics of the pest. Diapause results in differential regulation of hormonal and biochemical profiles, impose deleterious effects on the post-diapause development, reproductive physiology and population growth of C. partellus. The diapause, developmental and morphometric traits in C. partellus are governed by overdominance gene effects which mainly depend on parental diapause history. Four different biotypes of C. partellus viz., Hisar, Hyderabad, Parbhani and Coimbatore exist in India, suggesting that sorghum and maize genotypes need to be tested against these four populations to identify stable sources of resistance. The whole genome sequencing will be useful for understanding mode of action of different insecticides, mechanisms of detoxification and designing target-specific insecticides to develop appropriate strategies to manage C. partellus for sustainable crop production. The temporal distribution of mating systems among adults of diapause, non-diapause and/or ecologically diverse populations, and their behavioral and physiological consequences under a given demographic framework could be rewarding, and aid in to devising appropriate mating disruption techniques to suppress C. partellus population.

Solar radiation, temperature and the reproductive biology of the coral Lobactis scutaria in a changing climate

Coral reefs worldwide are at risk due to climate change. Coral bleaching is becoming increasingly common and corals that survive bleaching events can suffer from temporary reproductive failure for several years. While water temperature is a key driver in causing coral bleaching, other environmental factors are involved, such as solar radiation. We investigated the individual and combined effects of temperature, photosynthetically active radiation (PAR), and ultraviolet radiation (UVR) on the spawning patterns and reproductive physiology of the Hawaiian mushroom coral Lobactis scutaria, using long-term experiments in aquaria. We examined effects on spawning timing, fertilisation success, and gamete physiology. Both warmer temperatures and filtering UVR altered the timing of spawning. Warmer temperatures caused a drop in fertilisation success. Warmer temperatures and higher PAR both negatively affected sperm and egg physiology. These results are concerning for the mushroom coral L. scutaria and similar reproductive data are urgently needed to predict future reproductive trends in other species. Nonetheless, thermal stress from global climate change will need to be adequately addressed to ensure the survival of reef-building corals in their natural environment throughout the next century and beyond. Until then, reproduction is likely to be increasingly impaired in a growing number of coral species.

Assessing reproduction in wolverines (Gulo gulo): Fecal progesterone levels in zoo and wild females

Wolverines (Gulo gulo) populations are under threat by increased human activities. A better understanding of their reproductive physiology would benefit research and monitoring of this species. The use of enzyme immunoassay (EIA) to measure fecal progesterone metabolites (FPM) is a powerful tool to understand wildlife reproductive physiology, and a non-invasive method for use in both zoo and wild populations. The main objective of this study was to determine reproductive status in female wolverines using FPM levels, first by monitoring of longitudinal changes in FPM in zoo housed females in breeding situations and second to compare those values to FPM measured in feces obtained from wild females observed in the field during reproductively active periods (Dec–Apr). Female reproductive physiology was assessed by measuring FPM in three zoo housed wolverines to determine species-specific levels arising from ovulation encompassing embryonic diapause and ovarian reactivation (resumption of ovarian luteal activity after diapause) during pregnancy or pseudopregnancy, which in turn enabled verification of reproductive status in 15 wild wolverines, monitored over three years. In the zoo females, FPM levels were sustained at basal levels if ovulation and/or breeding did not occur. After ovulation, both pregnancy or pseudopregnancy exhibited a bi-phasic pattern of FPM increases, with a 4.9-fold increase above baseline during embryonic diapause and a further 4.4-fold increase after ovarian reactivation. FPM levels during pregnancy and pseudopregnancy were indistinguishable, thus increases in FPM levels are only a confirmation of ovulation, and not diagnostic for pregnancy. In wild females, assessment of FPM levels in samples collected from December to February was able to predict a potentially pregnant/reproductively active female with levels above 8200 ng/g dried feces, or non-reproductive (nonovulatory) female during that period with levels below 1700 ng/g. Wild wolverine FPM levels indicative of pregnancy aligned with field observations of denning and/or lactation. FPM levels from samples collected from March and April were inconclusive as levels could be attributed to females being either postpartum or non-reproductive at that time. Timing of ovarian reactivation, and subsequent elevation of FPM, varied among individuals suggesting caution is warranted when assessing only one fecal sample per female. Understanding all factors that may impact reproductive success is essential for effective species conservation, particularly for species with low reproductive rates, like the wolverine. This study has demonstrated the potentially useful incorporation of non-invasive fecal hormone analysis for investigation of physiological parameters and reproductive status in wild wolverine females.

Use of hormones in assessing reproductive physiology of humpback whales (Megaptera novaeangliae) from Juneau, Alaska

Humpback whales (Megaptera novaeangliae) in Southeast Alaska have been studied for over 50 years, and are largely considered a recovery success since the cessation of commercial whaling. Reproductive physiology is an important factor to consider in studying population health and can provide important insights into the drivers contributing to population abundance fluctuations. Validated assays for progesterone and testosterone were used on blubber biopsies from humpback whales (N = 33 whales, 71 samples) near Juneau, Alaska, in 2020 and 2021. Long-term sighting histories were used to confirm detected pregnancies with calf sightings the following year. Blubber samples were divided into two seasonal bins (early and late summer). Pregnant females sampled in both early and late summer of both 2020 and 2021 showed elevated progesterone concentrations compared to other reproductive states (p < 0.05). Progesterone concentrations in adult male whales (0.3 ± 0.2 ng/g) were not significantly different from lactating or resting female whales. Blubber testosterone concentrations in adult male humpback whales ranged from 0.05 to 1.1 ng/g, and mean concentrations were approximately double those of female whales in any reproductive state. Pregnancy was detected in 5 of 11 and 4 of 9 adult females in 2020 and 2021 respectively, yielding summer season pregnancy rates for sexually mature females at 0.45, and 0.44, respectively. Calving rates were 0.36 and 0.22 in 2020 and 2021, respectively, and the annual growth rate for this subpopulation was calculated at 2.6 % per annum. One female had successful pregnancies for four consecutive years. These results demonstrate the synergistic value of combining immunoreactive assays and long-term sighting histories to further knowledge of reproductive physiology in individual humpback whales, which can be expanded to assessing the health of a population or ecosystem.

Vitellogenin genes are transcribed in Culex quinquefasciatus ovary.

Culex quinquefasciatus, a cosmopolitan, domestic, and highly anthropophilic mosquito, is a vector of pathogenic arboviruses such as West Nile virus and Rift Valley virus, as well as lymphatic filariasis. The current knowledge on its reproductive physiology regarding vitellogenin expression in different tissues is still limited. In this study, we analysed the transcriptional profiles of vitellogenin genes in the fat body and ovaries of C. quinquefasciatus females during the first gonotrophic cycle. C. quinquefasciatus ovaries and/or fat bodies were dissected in different times during the first gonotrophic cycle and total RNA was extracted and used for reverse transcription polymerase chain reaction, quantitative real time-PCR, and in situ hybridisation. We confirmed the classical descriptions of the vitellogenic process in mosquitoes by verifying that vitellogenin genes are transcribed in the fat bodies of C. quinquefasciatus females. Using RNA in situ hybridisation approach, we showed that vitellogenin genes are also transcribed in developing ovaries, specifically by the follicle cells. This is the first time that vitellogenin transcripts are observed in mosquito ovaries. Studies to determine if Vg transcripts are translated into proteins and their contribution to the reproductive success of the mosquito need to be further investigated.

Reproductive status of a female white cockatoo (Cacatua alba) based on relationships among urofecal steroid hormone dynamics, molting, and body weight.

The detailed reproductive physiology of cockatoos based on gonadal hormone dynamics is unclear. In this study, we aimed to investigate ovarian activity by monitoring urofecal sex steroid hormone profiles in a captive female white cockatoo (Cacatua alba) and to noninvasively reveal basic reproductive physiology by comparing the hormone profiles with the laying dates, body mass changes, and molt progress. Urofeces were collected regularly for approximately 4 years from one female that frequently laid unfertilized eggs under single-rearing conditions. Urofecal progesterone (P4) and estradiol-17β (E2) were measured by enzyme immunoassay. In addition, body mass and the number of fallen feathers were measured periodically. The urofecal P4 concentration peaked at an average of 17.7 days after the start of the rise in urofecal E2 concentration, and egg laying began on the day after the peak urofecal P4 concentration. The clutch size was usually two eggs, with an average interval of 4.5 days between eggs in each egg-laying cycle. There was a significant correlation between the dynamics of E2 concentration in urofeces and body mass. The results strongly suggest that E2 and P4 reflect the follicle growth and ovulation status, respectively, and that noninvasive monitoring of hormone dynamics using urofeces can accurately capture ovarian activity in the white cockatoo. Furthermore, changes in body mass can predict follicular growth, and reproduction and molt are antagonistic.

Modulation of Melatonin Receptors Regulates Reproductive Physiology: The Impact of Agomelatine on the Estrus Cycle, Gestation, Offspring, and Uterine Contractions in Rats

Agomelatine is a pharmaceutical compound that functions as an agonist for melatonin receptors, with a particular affinity for the MT1 and MT2 receptor subtypes. Its mode of action is integral to the regulation of diverse physiological processes, encompassing the orchestration of circadian rhythms, sleep-wake cycles, and mood modulation. In the present study, we delve into the intricate interplay between agomelatine and the modulation of estrus cycles, gestation periods, offspring numbers, and uterine contractions, shedding light on their collective impact on reproductive physiology. Both in vivo and in vitro experiments were performed. Wistar Albino rats, divided into four groups: two non-pregnant groups (D1 and D2) and two pregnant groups (G1 and G2). The D1 and G1 groups served as control groups, while the D2 and G2 groups received chronic agomelatine administration (10 mg/kg). Uterine contractions were assessed in vitro using myometrial strips. Luzindole, a melatonin receptor antagonist, was employed to investigate the pathway mediating agomelatine's effects on uterine contractions. In in vivo studies, chronic agomelatine administration extended the diestrus phase (p&lt;0.05) in non-pregnant rats, prolonged the gestational period (p&lt;0.01), and increased the fetal count (p&lt;0.01) in pregnant rats. Additionally, agomelatine reduced plasma oxytocin and prostoglandin-E levels (p&lt;0.01) during pregnancy. In vitro experiments showed that agomelatine dose-dependently inhibited spontaneous and oxytocin-induced myometrial contractions. Luzindole (2 µM) reverse the agomelatine-induced inhibition of myometrial contractions. These findings suggest that agomelatine holds the potential to modulate diverse reproductive parameters during the gestational period, influencing estrus cycling, gestational progression, offspring development, and the orchestration of uterine contractions.

AMPK-like proteins and their function in female reproduction and gynecologic cancer.

Serine-threonine kinase (STK11), also known as liver kinase B1 (LKB1), is a regulator of cellular homeostasis through regulating the cellular ATP-to-ADP ratio. LKB1 is classified as a tumor suppressor and functions as the key activator of AMP-activated protein kinase (AMPK) and a family of serine-threonine kinases called AMPK-like proteins. These proteins include novel (nua) kinase family 1 (NUAK1 and 2), salt inducible kinase (SIK1), QIK (known as SIK2), QSK (known as SIK3 kinase), and maternal embryonic leuzine zipper kinase (MELK) on tightly controlled and specific residual sites. LKB1 also regulates brain selective kinases 1 and 2 (BRSK1 and 2), additional members of AMPK-like protein family, which functions are probably less studied. AMPK-like proteins play a role in variety of reproductive physiology functions such as follicular maturation, menopause, embryogenesis, oocyte maturation, and preimplantation development. In addition, dysfunctional activity of AMPK-like proteins contributes to apoptosis blockade in cancer cells and induction of the epithelial-mesenchymal transition required for metastasis. Dysregulation of these proteins occurs in ovarian, endometrial, and cervical cancers. AMPK-like proteins are still undergoing further classification and may represent novel targets for targeted gynecologic cancer therapies. In this chapter, we describe the AMPK-like family of proteins and their roles in reproductive physiology and gynecologic cancers.

A Review on the Potential Effects of Combination Treatments of Anti-microbial and Anti-inflammatory Drugs Towards Male Reproductive Physiology in Pneumonic Bucks

Pneumonia is the inflammation of lung parenchyma due to various organisms resulting in numerous manifestations and sequelae. The environment in the tropical regions provides optimal conditions for infection to occur in small ruminants. Mannheimiosis caused by Mannheimia haemolytica is the most frequent isolated bacteria causing pneumonia in small ruminants. The bacteria may cause an acute infection which can lead to death without proper diagnosis and treatment. To date, there are still scarce study on the effect of anti-microbial and anti-inflammatory treatments on reproductive physiology that warrants investigation. Hence, this review paper aims to focus on the possible effect of a combined usage of anti-microbial and anti-inflammatory treatments toward male reproductive physiology.

Biobanks, offspring fitness and the influence of developmental plasticity in conservation biology.

Mitigation of the widely known threats to the world's biodiversity is difficult, despite the strategies and actions proposed by international agreements such as the United Nations Framework Convention on Climate Change (UNFCCC) and the Convention on Biological Diversity (CBD). Nevertheless, many scientists devote their time and effort to finding and implementing various solutions to the problem. One potential way forward that is gaining popularity involves the establishment of biobank programs aimed at preserving and storing germplasm from threatened species, and then using it to support the future viability and health of threatened populations. This involves developing and using assisted reproductive technologies to achieve their goals. Despite considerable advances in the effectiveness of reproductive technologies, differences between the reproductive behavior and physiology of widely differing taxonomic groups mean that this approach cannot be applied with equal success to many species. Moreover, evidence that epigenetic influences and developmental plasticity, whereby it is now understood that embryonic development, and subsequent health in later life, can be affected by peri-conceptional environmental conditions, is raising the possibility that cryopreservation methods themselves may have to be reviewed and revised when planning the biobanks. Here, I describe the benefits and problems associated with germplasm biobanking across various species, but also offer some realistic assessments of current progress and applications.

Assessing the effects of a drought experiment on the reproductive phenology and ecophysiology of a wet tropical rainforest community.

Climate change is expected to increase the intensity and occurrence of drought in tropical regions, potentially affecting the phenology and physiology of tree species. Phenological activity may respond to a drying and warming environment by advancing reproductive timing and/or diminishing the production of flowers and fruits. These changes have the potential to disrupt important ecological processes, with potentially wide-ranging effects on tropical forest function. Here, we analysed the monthly flowering and fruiting phenology of a tree community (337 individuals from 30 species) over 7years in a lowland tropical rainforest in northeastern Australia and its response to a throughfall exclusion drought experiment (TFE) that was carried out from 2016 to 2018 (3years), excluding approximately 30% of rainfall. We further examined the ecophysiological effects of the TFE on the elemental (C:N) and stable isotope (δ13C and δ15N) composition of leaves, and on the stable isotope composition (δ13C and δ18O) of stem wood of four tree species. At the community level, there was no detectable effect of the TFE on flowering activity overall, but there was a significant effect recorded on fruiting and varying responses from the selected species. The reproductive phenology and physiology of the four species examined in detail were largely resistant to impacts of the TFE treatment. One canopy species in the TFE significantly increased in fruiting and flowering activity, whereas one understory species decreased significantly in both. There was a significant interaction between the TFE treatment and season on leaf C:N for two species. Stable isotope responses were also variable among species, indicating species-specific responses to the TFE. Thus, we did not observe consistent patterns in physiological and phenological changes in the tree community within the 3years of TFE treatment examined in this study.

Persisting Wolffian and Müllerian ducts in female and male southern tamanduas (Tamandua tetradactyla)?

The southern tamandua (Tamandua tetradactyla) and the giant anteater (Myrmecophaga tridactyla) belong to the anteater family Myrmecophagidae and both species share basic morphological characteristics including the general features of reproductive organs. However, in female and male giant anteaters, persisting Wolffian and Müllerian ducts have been observed that have not been described in the southern tamandua, so far. Therefore, the present study evaluated whether those persisting genital ducts of the opposite sex can be observed in the southern tamandua as well. For this purpose, the reproductive organs of adult roadkill male and female specimens were studied in Brazil. In female southern tamanduas, persisting Wolffian ducts extended from the opening of the uterovaginal canal into the sinus urogenitalis in cranial direction through the ventral wall of the uterovaginal canal and the uterus and followed the course of the uterine tubes until the lateral pole of the ovaries. Those ducts showed the same characteristics as described in giant anteaters and revealed similarities to male epididymal and deferent ducts. Furthermore, glandular structures in the wall of the urethra and the sinus urogenitalis were observed that showed microscopic characteristics corresponding to male prostate and bulbourethral glands, similarly to observations in female giant anteaters. In male southern tamanduas, on the contrary, only rudimentary tubules were found in the prostatic urethral wall while well-differentiated Müllerian ducts have been previously described in the male giant anteater. In conclusion, well-developed Wolffian ducts are a shared characteristic in both female southern tamanduas and female giant anteaters whereas well-developed Müllerian ducts are unique to male giant anteaters and only rudimentary Müllerian vestiges were observed in the male southern tamandua. Data on those persisting genital ducts are of interest for studies on reproductive biology and physiology of southern tamanduas and sexual development of mammalian species in general.

Progesterone circulation and follicular growth in adapted Bos taurus cows.

The creole breed Blanco Orejinegro (Bos taurus adapted) is an important animal genetic resource in Colombia. However, very little is known about the reproductive physiology of the breed. The objective was to determine the dynamics of progesterone circulation and follicular growth in Blanco Orejinegro cows throughout the estrous cycle. Fifteen cyclic Blanco Orejinegro cows were used and subjected to hormonal protocol for estrous and ovulation synchronization. Once the time of ovulation was identified by monitoring the ovarian dynamics with ultrasonography equipment. For description of the results, the mean was used as a measure of central tendency and the standard error of the mean. Statistical analysis was longitudinal descriptive. Blood samples were collected every 24 hr throughout the estrous cycle for serum quantification of progesterone (P4), monitoring of corpus luteum (CL) growth dynamics and follicular dynamics. It was possible to verify that 76.92% of the Blanco Orejinegro cows presented two follicular waves during the estrous cycle and the highest circulating levels of P4 (> 6.00 ng mL-1) were observed on the 14th day of the estrous cycle. It was concluded that the creole cows of the Blanco Orejinegro breed presented two follicular waves per estrous cycle. In addition to, the size of the CL was consistent with the secretion of progesterone presenting higher circulating levels at the end of the luteal phase.

Ovarian cycle, reproductive performance and breeding seasonality of Amazonian yellow-footed tortoises (Chelonoidis denticulatus) in the wild

Studies of the reproductive functional morphology of chelonians are important to understand the reproductive physiology, anatomy, and endocrinology of these species. However, data on the reproduction of this group have been difficult to obtain because of their cryptic habits and as a result the consequent inefficiency of conventional field methods in detecting individuals in the wild. In this study, we obtained reproductive organs from 347 adult female yellow-footed tortoises (Chelonoidis denticulatus), one of the most hunted and traded land vertebrates in South America, donated by local sellers in a wild meat market in the Peruvian Amazon. We described the species’ reproductive cycle and the influence of climatic factors on reproductive performance. Of the sampled females, 116 (33.4%) were gravid and 231 (66.6%) were non-gravid, including 215 vitellogenic (62.0%) and 16 non-vitellogenic (4.6%). The mean number of ovarian follicles per female declined from 28.5 (<10 mm diameter), to 7.1 follicles (20–40 mm) to 3.2 follicles> 40 mm. Gravid females had in average 3.7 shelled eggs in the oviduct, with a mean egg diameter of 53.7 mm. The estimated annual reproductive potential in gravid females was 5.1 eggs per clutch, ranging from one to 22 eggs. There was a strong positive relationship between the diameter of shelled eggs and the straight carapace length of gravid females. The final phase of the folicular growth, the most demanding energetic process in chelonian reproduction, correlated with annual rainfall peak, while oviposition was estimated to occur in the dry season. The yellow-footed tortoise should be considered an opportunistic seasonal breeder, though capable of reproducing throughout the year. Reproductive yields are linked to climatic events that influence food availability in the environment. To improve the sustainable use of this species, adult females should be harvested primarily during reproductive quiescence, from the end of the laying period in the late dry season to the mid-rainy season when large follicles appear, to avoid taking gravid females. Our results are useful not just to better understand the reproductive biology of terrestrial chelonians but can inform the conservation management of harvested species.

Abstract 2313: Na+/H+ exchanger 5 (NHE5) protein is a potential target for therapeutic interventions in altered Male Reproductive Physiology

Abstract 2313: Na+/H+ exchanger 5 (NHE5) protein is a potential target for therapeutic interventions in altered Male Reproductive Physiology

Coping with Oxidative Stress in Reproductive Pathophysiology and Assisted Reproduction: Melatonin as an Emerging Therapeutical Tool.

Infertility is an increasing global public health concern with socio-psychological implications for affected couples. Remarkable advances in reproductive medicine have led to successful treatments such as assisted reproductive techniques (ART). However, the search for new therapeutic tools to improve ART success rates has become a research hotspot. In the last few years, pineal indolamine melatonin has been investigated for its powerful antioxidant properties and its role in reproductive physiology. It is considered a promising therapeutical agent to counteract the detrimental effects associated with oxidative stress in fertility treatments. The aim of the present narrative review was to summarize the current state of the art on the importance of melatonin in reproductive physiology and to provide a critical evaluation of the data available encompassing basic, translational and clinical studies on its potential use in ART to improve fertility success rates.

Dietary Supplementation of Capsaicin Enhances Productive and Reproductive Efficiency of Chinese Crossbred Buffaloes in Low Breeding Season.

The present study investigated the role of dietary capsaicin (CPS) supplementation on milk yield (liters/head) and milk composition (total solids, lactose, albumin, protein, fat, milk urea nitrogen (MUN), somatic cell count (SCC) and somatic cell score (SCS), serum metabolites (lipoprotein esterase (LPL) and aspartate aminotransferase (AST)), and reproductive physiology (follicular development, estrus response, ovulation and pregnancy) following synchronization during the low breeding season. One hundred (n = 100) crossbred buffaloes were randomly assigned to four dietary groups consisting of CPS supplementation dosages (0, 2, 4 or 6 mg/kg of total mixed ration; TMR) as CPS-0 (n = 26), CPS-2 (n = 22), CPS-4 (n = 25) and CPS-6 (n = 27), respectively, in a 30-day feed trial. The results revealed that the CPS-4 group of buffaloes had a better estrus rate (72%) along with improved (p < 0.05) ovulatory follicle diameter (13.8 mm), ovulation rate (68%) and pregnancy rate (48%) compared to other treatment groups. Milk yield improved (p < 0.05) in CPS-4 supplemented buffaloes after day 20 of the trial, comparatively. There was a significant effect (p < 0.05) of milk sampling day (day 30) on total milk solids, lactose, milk protein and MUN levels, whereas lactose, MUN, SCC and SCS were influenced by supplementation dosage (CPS-4). Glucose levels were affected in buffaloes by sampling time (artificial insemination (AI) and 50-day post-AI) and CPS-dose (CPS-4 and CPS-6), respectively. LPL level changed in CPS-2 and CPS-4 groups at AI time and 50 days after AI. In addition, the AST level was different in CPS-4 at AI time and 50 days after AI. Therefore, our data suggest that a medium dose (~4 mg/kg of TMR) of CPS provided a better response in the form of milk yield, milk composition, serum metabolites and reproductive performance in crossbred buffaloes during the low breeding season.

Optical coherence tomography for dynamic investigation of mammalian reproductive processes.

The biological events associated with mammalian reproductive processes are highly dynamic and tightly regulated by molecular, genetic, and biomechanical factors. Implementation of live imaging in reproductive research is vital for the advancement of our understanding of normal reproductive physiology and for improving the management of reproductive disorders. Optical coherence tomography (OCT) is emerging as a promising tool for dynamic volumetric imaging of various reproductive processes in mice and other animal models. In this review, we summarize recent studies employing OCT-based approaches toward the investigation of reproductive processes in both, males and females. We describe how OCT can be applied to study structural features of the male reproductive system and sperm transport through the male reproductive tract. We review OCT applications for in vitro and dynamic in vivo imaging of the female reproductive system, staging and tracking of oocytes and embryos, and investigations of the oocyte/embryo transport through the oviduct. We describe how the functional OCT approach can be applied to the analysis of cilia dynamics within the male and female reproductive systems. We also discuss the areas of research, where OCT could find potential applications to progress our understanding of normal reproductive physiology and reproductive disorders.