Intact Females Research Articles

Levonorgestrel maintains goal-directed behavior in habit-trained intact female rats

Hormonal contraceptives are utilized by millions of women worldwide. However, it remains unclear if these powerful endocrine modulators may alter cognitive function. Habit formation involves the progression of instrumental learning as it goes from being a conscious goal-directed process to a cue-driven automatic habitual motor response. Dysregulated goal and/or habit is implicated in numerous psychopathologies, underscoring the relevance of examining the effect of hormonal contraceptives on goal-directed and habitual behavior. This study examined the effect of levonorgestrel (LNG), a widely used progestin-type contraceptive, on the development of habit in intact female rats. Rats were implanted with subcutaneous capsules that slowly released LNG over the course of the experiment or cholesterol-filled capsules. All female rats underwent operant training followed by reward devaluation to test for habit. One group of females was trained at a level that is sub-threshold to habit, while another group of females was trained to a level well over the habit threshold observed in intact females. The results reveal that all sub-threshold trained rats remained goal-directed irrespective of LGN treatment, suggesting LNG is not advancing habit formation in female rats at this level of reinforcement. However, in rats that were overtrained well above the threshold, cholesterol females showed habitual behavior, thus replicating a portion of our original studies. In contrast, LNG-treated habit-trained rats remained goal-directed, indicating that LNG impedes the development and/or expression of habit following this level of supra-threshold to habit training. Thus, LNG may offset habit formation by sustaining attentional or motivational processes during learning in intact female rats. These results may be clinically relevant to women using this type of hormonal contraceptive as well as in other progestin-based hormone therapies.

Indirect methods for predicting the body composition of sheep of different sex classes

The aim was to evaluate the correlation and develop regression equations for the body composition of sheep of different sex classes, obtained by the comparative slaughter method, using the composition of the neck region and loin eye area (LEA). Forty-five sheep of three sex classes (15 intact males, 15 castrated males and 15 females) received three feeding levels (ad libitum or restrictions of 70 or 80% of ad libitum intake). Animals were distributed in a 3×3 factorial arrangement, with 5 repetitions. The LEA showed: positive correlation with empty body weight, fasting body weight, meat, protein, ether extract and water (p < 0.01), for all sex classes; with bones for intact males and females (p < 0.01); with ash content for intact males and a moderate correlation for castrated males (p < 0.01). The neck was correlated with empty body weight, fasting body weight, meat, protein, ether extract, water and energy in all sex classes (p < 0.01); and moderate correlation with bone (r=0.58) and ash (r=0.67) for intact males. Intact males showed higher R² values in their prediction equations in relation to the other sex classes.

Treatment of Oral Disease in Eight Pet Pot-Bellied Pigs (Sus scrofa domesticus): A Case Series.

Evidence of porcine oral pathology in client-owned domestic pigs has been reported in recent literature. The most common abnormalities are missing teeth and periodontal disease. This case series reviews the diagnosis and treatment of dental disease in 8 pet Vietnamese Pot-Bellied Pigs (Sus scrofa domesticus) over a 6-year period (2015-2021). Inclusion criteria included pigs over 1 year of age that had at least 2 sequential visits involving photographs, full-mouth intraoral radiographs, and dental charting. Eight pigs were identified for study inclusion. The study population included 4 castrated males, 3 spayed females, and 1 intact female. The 8 subjects had a total of 28 visits. Fifty-five intraoral dental extractions were performed and complete healing of 44 extraction sites was observed (11 sites were lost to follow up). Canine tooth reduction was performed on 52 tusks in 7 pigs with exposure of 1 pulp that was treated by partial pulpectomy and direct pulp capping. Restoration of carious lesions was performed on 4 teeth. The most commonly extracted teeth were the right and left maxillary first molars (10 of 47 teeth). Reasons for tooth extraction included: periodontal disease, complicated crown fracture, nonvital +/- periapical pathology, and persistent deciduous teeth. Additional treatments ranged from type 1 crown lengthening with restoration of carious lesions, tusk trimming, closed and open root planing, dental extractions, ultrasonic scaling, and polishing. This article stresses the importance of routine dental healthcare and early intervention for periodontal disease in pigs.

Anti-Müllerian hormone and inhibin-B concentrations vary cyclically in nonovulating queens within reference ranges established for determining gonadal status in cats.

To define cyclic changes in anti-Müllerian hormone (AMH), inhibin-B, and progesterone concentrations and establish statistically valid, population-based clinical reference ranges in queens. Cyclic queens (fertile, n = 6; infertile, 6) from an institutional breeding colony were blood sampled longitudinally, each for over 2 months, between November 2021 and February 2022, and residual serum samples from intact (n = 205) and ovariohysterectomized (49) queens from clinical submissions were used to establish reference ranges for intact and spayed females. AMH and inhibin-B were measured using commercially available ELISAs, progesterone was measured using an in-house ELISA, and 90% CIs were calculated from these data. AMH and inhibin-B fluctuated in a highly correlated, cyclic pattern in 3 queens that did not ovulate immediately, whereas AMH declined as progesterone increased, indicative of ovulation, which occurred spontaneously early in the sampling period in 3 others; statistically valid reference ranges were established in intact and ovariohysterectomized females. Cyclic changes in hormone profiles were defined, providing relevant context for interpreting results in cases seeking to determine gonadal status (presence or absence of gonadal tissue) on the basis of established, population-based reference ranges reported here for cats for the first time.

Abstract B039: Effect of cross-sex testosterone therapy on Pik3ca-driven breast cancer incidence in mice

Abstract Background: The majority of transmasculine individuals—assigned female at birth—pursue gender-affirming testosterone therapy (TT) to treat their gender dysphoria. It remains unknown the extent to which TT modulates the breast, including breast cancer (BC) risk, in transmasculine individuals. Given that hormone regulation of breast development is similar in mice and humans, mouse models are an excellent methodology to understand the effect of TT on BC development. We used a BC mouse model, MMTV-Cre Pik3caf/wt, to investigate the effect of testosterone on estrogen receptor positive (ER+) BC development. Method: Immunohistochemistry confirmed that our MMTV-Cre Pik3caf/wt tumors are ER+. We established 5 study arms: female controls (n=4), oophorectomized female controls (n=6), male mice (n=5), female mice receiving weekly 400 µg s.c. of testosterone cypionate (n=5), and oophorectomized female mice receiving weekly testosterone cypionate (n=5). Mammary tumor development was monitored weekly; palpable tumors were measured 3x a week. Mice were euthanized when their largest tumor reached 1cm, or if multiple tumors arise, when the combined tumor burden reaches 2 cm. Mice that have not reached endpoint by 48 weeks of age were euthanized and censored. The total number of tumors were observed during necropsy. Results: All 4 female controls developed a mean of 4 tumors each and were euthanized at around 35 weeks as the largest tumor reached 1 cm. The remaining mice were euthanized study endpoint of 48 weeks. Only 1 of 5 female mice receiving testosterone had a macroscopic tumor at 48 weeks. Hence, the total number of tumors developed among female mice receiving testosterone are similar or lower than female controls. Three out of 6 of oophorectomized females developed an average of 2 tumors while 2 of 5 female oophorectomized mice receiving testosterone developed 3 tumors each. Thus, when compared to intact females, oophorectomy appears to increase the lag time to Pik3ca tumor development. Lastly, 1 of 5 male mice developed 4 tumors. Conclusion: This pilot study demonstrated that testosterone does not increase ER+ BC incidence in Pik3ca-transgenic mice. Findings in oophorectomized mice suggest that aromatization of testosterone to estradiol may not contribute significantly to tumor development in these mice. Our findings provides insights into about BC risk associated with TT in transmasculine individuals. More studies are warranted to understand the health effects of gender-affirming hormone therapy, and reduce healthcare disparities in the transgender community. Citation Format: Lin Wang, Abhishek Thavamani, Erica S. Massicott, Vanessa C. Bret-Mounet, Joseph Abirached, John G. Clohessy, Gabrielle M. Baker, Gerburg M. Wulf, Yujing Jan Heng. Effect of cross-sex testosterone therapy on Pik3ca-driven breast cancer incidence in mice [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B039.

Pilot study on the distribution of caseous lymphadenitis in Korean native goats and the relationship between sex and age in disease occurrence

Caseous lymphadenitis (CLA) caused by Corynebacterium pseudotuberculosis is a chronic disease that affects goats. The Korean native goat (KNG) is the most popular goat breed raised in Korea. In this study, the distribution of CLA in the KNG population and the relevance of sex and age in disease development were determined. From March 2020 to February 2021, 1,177 KNGs from 110 farms were assessed. The distribution of CLA in animals was determined by a veterinary inspector who performed gross examinations of goat carcasses and confirmed diagnoses via polymerase chain reaction and bacteriological examination. The CLA detection rate in the KNG population was 19.80%, and more than half of the farms were affected by the disease (56.36%). A statistically significant difference was observed among the sex groups, with castrated males (13.98%) having the lowest detection rate, followed by intact males (22.48%) and females (24.09%), suggesting that castration has a positive effect on reducing the risk of CLA (p < 0.05). In terms of age groups, an increased detection rate of 28.16% was observed in the late adult (>2 years) group. Phylogenetic analysis indicated that the RNA polymerase beta subunit-encoding gene can effectively differentiate biovar ovis from biovar equi and can be used for further epidemiological studies of C. pseudotuberculosis. This is the first nationwide surveillance study of CLA distribution to confirm the continuous occurrence of CLA in Korean goat farms. Future studies should include risk factor analyses of CLA based on herd levels to prevent and control this disease in Korea.

SAT644 Gender Affirming Hormone Therapy (GHAT) In Adult Male-to-female Mice Increases Cortical And Trabecular Bone, Resulting In An Increase In Bone Strength

Abstract Disclosure: J.D. Zajac: None. T. Nie: None. V. Venkatesh: None. S. Golub: None. K. Stok: None. R. Desai: None. D.J. Handelsman: None. R.A. Davey: None. There are conflicting reports of the effects of GAHT on bone health and fracture risk in adult transgender women, and the underlying changes are poorly understood. We aimed to determine the effects of GAHT administered during adulthood on bone microarchitecture and strength in a mouse model of male-to-female transition. To model male-to-female transition in adults, C57BL/6 male mice aged 16 weeks that had reached peak bone mass were administered an estradiol-filled silastic implant (∼1.3mg) intraperitoneally for 12 weeks. Controls included vehicle treated intact males and females, n=9-10/group. At study end, serum sex steroids were determined by LCMS/MS, femoral bone microarchitecture by μ-CT, and strength by 3-point bending. Mean serum estradiol was 4.7-fold higher in males treated with estradiol (91.8±10.4 pg/mL) than the peak estradiol levels observed during the proestrus stage of the estrus cycle in adult female mice (19.4±13.5 pg/mL, Handelsman, 2020). Estradiol treatment in males increased the endocortical deposition of bone evidenced by an increase in cortical thickness (mm)(P<0.05) and a decrease in medullary volume (mm3)(P<0.05) compared to male and female controls. Periosteal circumference was not effected by estradiol treatment in males compared to controls. Trabecular bone volume/tissue volume (%) was 4-fold higher in estradiol treated males compared to male controls and 12-fold higher than female controls due to an increase in trabecular number (μm)(P<0.0001). The increase in both cortical and trabecular bone contributed to increased bone strength, as the maximum force (N) the bone could withstand prior to fracture was 2-fold higher in males treated with estradiol compared to both male and female controls (P<0.0001). Measurement of the material properties of the femur showed an increase in ultimate stress (MPa)(P<0.001) and elastic modulus (MPa)(P<0.01) in males following estradiol treatment compared to male controls, indicative of increased rigidity. In this model of adult male-to-female transition, supraphysiological levels of estradiol in male mice increases cortical and trabecular bone mass leading to increased bone strength. The increased rigidity of the femur following estradiol treatment suggests increased bone mineral content. It may be possible therefore, to preserve bone health and prevent fractures in trans women treated with GAHT, however a dose of estradiol that protects the bone without adverse side effects needs to be identified. Presentation: Saturday, June 17, 2023

Effect of Sex and Cross-Sex Hormone Treatment on Renal Monocarboxylate-Transporter Expression in Rats.

Proton- and sodium-dependent monocarboxylate transporters (MCTs/SMCTs) are determinants of renal clearance through the renal reabsorption of monocarboxylate substrates. Prior studies with intact females and males, ovariectomized females and castrated males have revealed the hormonal regulation of renal monocarboxylate-transporter expression, prompting investigation into the regulatory role of individual hormones. The aim of the present study is to evaluate the effect of exogenous sex and cross-sex hormones on renal MCT1, MCT4, CD147 and SMCT1 mRNA and membrane-bound protein expression. Ovariectomized (OVX) females and castrated (CST) male Sprague Dawley rats received estrogen and/or progesterone, testosterone, or a corresponding placebo treatment for 21 days prior to kidney collection. The quantitative measurement of mRNA and membrane-protein levels were conducted using qPCR and Western blot. Quantitative analysis revealed the combination estrogen/progesterone treatment reduced membrane MCT1 and 4 expression and increased SMCT1 expression, while testosterone administration increased MCT1 membrane-protein expression. Correlation analysis indicated that plasma 17β-estradiol was negatively correlated with MCT1 and MCT4 membrane expression, while testosterone was positively correlated. In contrast, SMCT1 membrane expression was positively correlated with 17β-estradiol and progesterone concentrations. MCT1, MCT4, CD147 and SMCT1 renal expression are significantly altered in response to female and male sex hormones following sex and cross-sex hormone treatment in OVX and CST rats. Further studies are needed to understand the complex role of sex hormones, sex hormone receptors and the impact of puberty on MCT/SMCT regulation.

Risk Factors for Patellar Luxation in Dogs in the Philippines

A retrospective case-control study was conducted on dogs with patellar luxation who presented to the Veterinary Teaching Hospital Diliman Station-Companion Animal Clinic between January 1, 2010, and December 31, 2019. There was a total of 73 dogs were diagnosed with patellar luxation. The majority of the dogs presented with limping, and the causes were mostly unknown. Unilateral medial patellar luxation was the most common type (21.92%). The average age of patients with patellar luxation was 3.24 years old. Puppies are 0.03 less likely to be diagnosed with patellar luxation, while juveniles are 3.74 times more likely, and mature adults are 2.19 times more likely to be diagnosed. The affected dogs included intact males (47.95%), neutered males (4.11%), and intact females (47.95%). The average weight of the affected dogs was 8.39 kg and the majority (35.62%) had a body condition score of 5/9. The Pomeranian was the most common breed for patellar luxation, followed by the mixed breed Shih Tzu, Toy Poodle, and Chihuahua. Mixed breeds are 0.39 times less likely, and dogs fed with dry dog food are 0.51 times less likely to develop the condition. Age and breed were also significantly associated with patellar luxation.

Aldosterone-progesterone relationship in sexually intact Chihuahua bitches

BackgroundAldosterone represents an important target of heart failure therapy and may be a valuable indicator of the renin-angiotensin-aldosterone system activity. However, its assessment might be challenging because of the effect of individual factors. In a recent study, intact female dogs showed the highest value of urinary aldosterone-to-creatinine ratio (UAldo:C) compared to other sex categories. In humans and rodents, an influence of progesterone has been reported by several studies. To our knowledge, the relationship between aldosterone and progesterone has not yet been investigated in dogs. The aim of this prospective study was to investigate this relationship in sexually intact Chihuahua females, measuring both hormones twice in the same bitch, that is in anoestrus when progesterone concentrations are baseline and in dioestrus when they are high.ResultsThe study population consisted of 14 sexually intact Chihuahua bitches. Serum progesterone (34.06 (21.17–44.90) vs. 0.19 [0.13–0.38] ng/ml; P < 0.001) and urinary aldosterone (9886.98 ± 5735.22 vs. 5005.72 ± 2127.73 pg/ml; P = 0.01) were significantly higher in dioestrus compared to anoestrous. Urinary aldosterone-to-creatinine ratio was higher in dioestrus compared to anoestrus (4.16 [3.17–6.80] vs. 3.39 ± 1.64 µg/g), but it did not reach the statistical significance (P = 0.056). Serum progesterone showed a moderate positive correlation with urinary aldosterone (ρ = 0.638, P < 0.001) and UAldo:C (ρ = 0.516, P = 0.005).ConclusionsThe results of the present study suggest the existence of a progesterone-aldosterone relationship in canine species, indicating that sex and phase of reproductive cycle should be taken into account when interpreting aldosterone concentrations. Further studies are needed to confirm these results on a larger canine population and to identify the underlying mechanisms in this species.

Abstract 055: Estrogen And Smooth Muscle Cell Estrogen Receptor Alpha Modulate Arterial Stiffness

Background: Arterial stiffness increases with age and contributes to cardiovascular disease. Although sex differences in arterial stiffness are clinically observed, the underlying mechanisms are unknown. Specifically, the role of estrogen (E2) and estrogen receptor alpha (ERα) in sex-dependent differences in arterial stiffness have not been defined. We hypothesize that E2 and ERα contribute to sex differences in arterial stiffness. Methods/Results: We measured aortic pulse wave velocity, an index of arterial stiffness, at 3, 12, and 18 months old, in male and female mice. Arterial stiffness increased in males at 12 and 18m but was delayed until 18m in females (p&lt;0.05). Circulating E2 decreased with age in females (p&lt;0.05), suggesting a link between estrogens and arterial stiffness. In young female mice, arterial stiffness increased with ovariectomy (OVX) versus sham surgery but was restored in OVX mice plus E2 pellet (p&lt;0.05). Aortic gene expression for the vasoprotective angiotensin II type 2 receptor (AT2R) decreased with OVX versus sham and was restored in OVX mice plus E2 pellet (p&lt;0.05). These data suggest a link between arterial stiffness, E2, and AT2R. We therefore created novel SMC-specific ERα knockout (SMC-ERα-KO) mice to assess the role of SMC-ERα in sex differences in arterial stiffness. Differences in arterial stiffness with age persist in ERα-intact mice, but 18m SMC-ERα-KO males and females exhibited less stiffness vs. age-matched ERα-intact littermates (p&lt;0.05). Trends persist in repeat PWV measures at 12 and 16-18m in individual males and females. Blood pressure (via telemetry) did not differ between 18m intact and KO males or females (p=0.73). In young ERα-intact females, OVX increased stiffness and decreased aortic AT2R expression, while OVX had no effect in SMC-ERα-KO females (all p&lt;0.05), supporting a role for E2 and SMC-ERα in arterial stiffness. Conclusion: These data suggest that estrogen contributes to sex differences in arterial stiffness and that with advancing age, SMC-ERα is unliganded due to the loss of estrogen and contributes to arterial stiffness in females, potentially via alterations in vascular AT2R function. These results also suggest a detrimental role for SMC-ERα in aging-associated arterial stiffness in males.

TRANSGENERATIONAL EFFECTS OF PRENATAL STRESS ON MEMORY AND EXPRESSION OF THE INSULIN-LIKE GROWTH FACTOR 2 GENE IN THE OFFSPRING BRAIN

Stress effects on pregnant female disrupt the behavior and cognitive abilities of their offspring not only of the first, but also of the subsequent generations. A similar transgenerational effect on the offspring phenotype can be exerted by various stress factors that affect fathers before conception. The purpose of the study was to reveal the transgenerational effect of stress in female rats from 15–19 days of pregnancy on memory and expression of the insulin-like growth factor 2 (Igf2) gene in the brain of male and female offspring, as well as the effect of additional stress in the stress-restress paradigm in prenatally stressed male rats before conception on the memory and expression in the brain Igf2 of their offspring of both sexes. We have shown that prenatally stressed males and their next-generation male offspring show improved memory in the passive avoidance test, increased Igf2 expression in the hippocampus and cortex. Females, descendants of prenatally stressed males, on the contrary, showed a decrease in the duration of memory retention, Igf2 expression in the hippocampus and cortex. Additional stressing of prenatally stressed males before mating with intact females worsened memory and the duration of its retention, reduced Igf2 expression in the brain of the offspring of both sexes. We concluded that the transgenerational effects of prenatal stress on memory and Igf2 expression in the brain depend on the sex of the offspring, and prenatal stress itself in males contributes to memory impairment and a decrease in Igf2 expression in the offspring brain if such males were additionally stressed before mating.

Effects of daily exposure to peat smoke on the reproductive and nervous systems in male white rats

Introduction. The regular occurrence of large-scale peat fires is an urgent medical and environmental problem of the modern scientific community. The peat smoke is a complex mixture of pollutants that have a serious impact on air quality and public health. &#x0D; Materials and methods. Adult male rats were exposed to peat smoke for 24 hours, the concentrations of PM2.5 and CO were 0.92±0.08 mg/m3 and 40.8±1.9 mg/m3, respectively. After exposure an open field examination, EEG examination and histological analysis of the testes and brain were performed, after which they were mated with intact females. Postnatal death of offspring in the first week of life, body weight, behaviour and electroencephalography indicators during puberty were evaluated.&#x0D; Results. There was showed an increase in motor activity, anxiety, and violation of EEG indicators in rat males exposed to peat smoke. Both an increase in shadow cells and degeneratively altered neurons in the nervous tissue were found. No changes were detected in the testes. Exposure to peat smoke during conception increased stillbirth and mortality of offspring during the first week of life, but did not affect weight gain. Violation of behaviour structure was recorded only in females offspring. An increase in slow-wave activity of the brain in males offspring was revealed.&#x0D; Limitations. The study was limited to studying the effects of a single 24-hour exposure to peat smoke on outbred white rats.&#x0D; Conclusion. A single peat smoke exposure for 24 hours at a concentration of PM2.5=0.92±0.08 mg/m3 and CO=40.8±1.9 mg/m3 leads to significant morphological and functional changes in the CNS. In the absence of a gonadotoxic effect, peat smoke exposure on males before mating causes specific changes in the behavior and bioelectrical activity of the brain of their offspring.

Delayed estrogen actions diminish food consumption without changing food approach, motor activity, or hypothalamic activation elicited by corticostriatal µ-opioid signaling.

Mu-opioid receptor (μ-OR) signaling in forebrain sites including nucleus accumbens (Acb) and ventromedial prefrontal cortex (vmPFC) modulates reward-driven feeding and may play a role in the pathophysiology of disordered eating. In preclinical models, intra-Acb or intra-vmPFC μ-OR stimulation causes overeating and vigorous responding for food rewards. These effects have been studied mainly in male animals, despite demonstrated sex differences and estrogen modulation of central reward systems. Hence, the present study investigated sex differences and estrogen modulation of intra-Acb and intra-vmPFC μ-OR-driven feeding behaviors. First, the dose-related effects of intra-Acb and intra-vmPFC infusions of the μ-OR-selective agonist, DAMGO, were compared among intact female, ovariectomized (OVX) female, and intactmale rats. The DAMGO feeding dose-effect function was flattened in intact females relative to the robust, dose-dependent effects observed in OVX females and intact males. Thus, in intact females, intra-Acb DAMGO failed to elevate food intake relative to vehicle, while intra-vmPFC DAMGO elevated food intake, but to a smaller degree compared to males and OVX females. Next, to explore the possible role of estrogen in mediating the diminished DAMGO response observed in intact females, OVX rats were given intra-Acb or intra-vmPFC infusions of DAMGO either immediately after a subcutaneous injection of 17-beta-estradiol 3-benzoate (EB; 5 μg/0.1 mL) or 24 h after EB injection. Intra-Acb DAMGO effects were not changed at the immediate post-EB time point. At the delayed post-EB timepoint, significant lordosis was noted and the duration of intra-Acb DAMGO-driven feeding bouts was significantly reduced, with no change in the number of bouts initiated, locomotor hyperactivity, or Fos immunoreactivity in hypothalamic feeding and arousal systems. Similarly, EB failed to alter the motor-activational effects of intra-vmPFC DAMGO while reducing feeding. These findings indicate that delayed, presumably genomically mediated estrogen actions modulate the μ-OR-generated motivational state by reducing consummatory activity while sparing goal-approach and general arousal/activity. The results additionally suggest that EB regulation of consummatory activity occurs outside of forebrain-μ-OR control of hypothalamic systems.

Descriptive analysis of haemangiosarcoma occurrence in dogs enrolled in the Golden Retriever lifetime study.

Haemangiosarcoma is a relatively common malignant tumour in dogs, and one of the primary outcomes of interest for the Golden Retriever Lifetime Study. This study collects longitudinal data and samples from a cohort of golden retrievers, with the aim of identification of nutritional, genetic, environmental, lifestyle and reproductive risk factors for cancers and other important diseases in dogs. This analysis describes the accumulating data and samples, which are available for use by researchers to fulfil the study's objectives. As of September 2022, 233/3044 dogs enrolled in the study had been diagnosed with haemangiosarcoma (7.65%), with an incidence rate of 1.10 cases per 100 dog-years. Visceral haemangiosarcoma was the most common, affecting 211/3044 study dogs (6.9%). One hundred and twenty eight visceral haemangiosarcoma diagnoses specified the presence of splenic tumours (60.7%) and 119 specified the presence of cardiac tumours (56.4%). The probability of remaining without a haemangiosarcoma diagnosis declined from 100% from approximately 4 years of age, to a 12 year probability of 91.1% in intact females (95% CI 84.4%-98.3%), 60.7% in neutered females (95% CI 41.6%-88.6%), 72.9% in intact males (95% CI 62.9%-84.6%) and 70.0% in neutered males (95% CI 53.4%-92.0%). The 1 year survival probability for visceral haemangiosarcoma was 1.42% (95% CI 0.37%-5.47%); for cutaneous haemangiosarcoma, it was 84.6% (95% CI 67.1%-99.99%). The accumulated data and samples are a considerable resource for further investigation of canine haemangiosarcoma and have a potential role in translational medicine.

Reference Range of Kaolin-Activated Thromboelastography (TEG) Values in Healthy Pet Rabbits (Oryctolagus cuniculus).

Thromboelastography (TEG) is a viscoelastic technique that allows the examination of both cellular and plasma protein clotting factors. Thromboelastography helps to investigate the underlying coagulopathy and to monitor therapeutic modalities. Although viscoelastic techniques have been used in human and veterinary medicine, reference ranges in pet rabbits are missing. The objective of this study is to establish the reference-range values of TEG parameters in healthy pet rabbits. 24 healthy pet rabbits of different breeds were included: 16 crossbreeds, four Californians, two lops, one lionhead, and one angora. Four rabbits were less than one year old and 20 were older than one year. Twelve rabbits were neutered females, 10 neutered males, and two were intact females. Health status was assessed through a physical examination, a complete blood work, and a coagulation profile. A TEG 5000 Thromboelastograph Hemostasis System was used with kaolin-activated citrated whole blood. All samples were analysed 30 min postextraction. The TEG reference ranges were reaction time (R) 1.4-6.9 min; clot formation time (K) 0.8-2.2 min; α angle 65.8-82.2 degrees; maximal amplitude (MA) 53.7-73.5 mm; measure of clot strength/firmness (G-value) 5796.6-13,885.9 dyn/cm2; and percentage of clot lysis in 30 min (LY30%) 0-41.5%. This study provides the reference ranges of TEG in pet rabbits.

Clinicopathological Diversity and Epidemiological Aspects of Canine and Feline Mammary Gland Tumors in Tehran: A Survey (2020-2022)

Background: Mammary tumors are common in dogs and cats. They are models for investigating carcinogenesis and designing treatment protocols that benefit human beings. Senescence, sex, and reproductive status affect the development of such neoplasms. Objectives: In Iran’s absence of a national animal tumor registry, the present study determined clinicopathological and epidemiological aspects of canine and feline mammary tumors in referral cases of four veterinary practices across Tehran from 2020 to 2022. Here, the incidence and types of canine and feline mammary tumors are described, in addition to sex, reproductive status, age, breed, the affected mammary gland(s), grades, lymphatic invasion, and lymph node metastases. Methods: All canine and feline patients with masses in the mammary gland region were considered in this study. The resected tumors and occasional lymph nodes were macroscopically scrutinized. Hematoxylin-Eosin slides were reviewed by light microscopy and immunohistochemistry was utilized when necessary. Results: Of the 76 dogs and eight cats, 100% were females, and the majority were intact. Most patients were 10-11 years old. Purebreds were the most frequent referrals. In some patients, more than one mammary gland had developed neoplasm, i.e. 141 affected glands in 76 bitches and nine affected glands in eight queens. Tumors were presented in both chains and even on the ventral midline, with an increased preponderance of caudally located glands. Thus, the caudal-most glands, i.e. inguinal and caudal abdominal glands, constituted 31.2% and 66.7% of the affected glands in bitches and queens, respectively. Intraductal papillary carcinoma (17%) and complex carcinoma (16.3%) had the highest incidence in dogs. The most commonly observed lesions in cats were lobular hyperplasia with atypia, and duct ectasia, each encompassing 22.3% of the affected glands. Most canine neoplasms were grade I (90.3%), while grade II neoplasms had the highest incidence in cats (50%). Lymphatic invasion and lymph node metastases were seen in canine anaplastic carcinoma, solid carcinoma, and complex carcinoma, as well as feline comedocarcinoma and tubular carcinoma. Conclusion: The risk of developing malignant tumors increases as the individual ages, and generally, caudally located mammary glands in intact purebred females are at increased risk. Moreover, anaplastic carcinomas must be precisely examined, both clinically and histopathologically, for lymph node metastases.

Estrogen modulation of cortical spreading depression

Background and aimsCortical spreading depression (CSD), a transient neuronal and glial depolarization that propagates slowly across the cerebral cortex, is the putative electrophysiological event underlying migraine aura and a headache trigger. Migraine is three times more prevalent in women than men, linked to circulating female hormones. High estrogen levels or estrogen withdrawal may be a migraine trigger for many women. We, therefore, aimed to examine whether sex, gonadectomy, and female hormone supplementation and withdrawal affect the susceptibility to CSD.MethodsTo determine CSD susceptibility, we recorded the frequency of CSDs triggered during 2-h topical KCl application in intact or gonadectomized female and male rats, without or with estradiol or progesterone supplementation via daily intraperitoneal injections. Estrogen or progesterone treatment followed by withdrawal was studied in a separate cohort. To take the first step towards identifying potential mechanisms, we studied glutamate and GABAA receptor binding using autoradiography.ResultsThe CSD frequency in intact female rats was higher than intact male and ovariectomized rats. We did not detect a change in CSD frequency during different stages of the estrous cycle in intact females. Daily estrogen injections for three weeks did not change CSD frequency. However, one-week estrogen withdrawal after two weeks of treatment significantly increased CSD frequency compared with the vehicle group in gonadectomized females. The same protocol of estrogen treatment and withdrawal was ineffective in gonadectomized males. In contrast to estrogen, daily progesterone injections for three weeks elevated CSD susceptibility, and one-week withdrawal after two weeks of treatment partially normalized this effect. Autoradiography did not reveal significant changes in glutamate or GABAA receptor binding density after estrogen treatment and withdrawal.ConclusionsThese data suggest that females are more susceptible to CSD, and sexual dimorphism is abrogated by gonadectomy. Moreover, estrogen withdrawal after prolonged daily treatment enhances CSD susceptibility. These findings may have implications for estrogen-withdrawal migraine, although the latter tends to be without aura.

Inflammaging in domestic dogs: basal level concentrations of IL-6, IL-1β, and TNF-α in serum of healthy dogs of different body sizes and ages.

Inflammaging, a "hallmark of aging," refers to a chronic, progressive increase in the proinflammatory status of mammals as they age, and this phenotype has been associated with many age-related diseases, including cardiovascular disease, arthritis and cancer. Though, inflammaging research is common in humans, there is a lack of data for this process for the domestic dog. Here, serum concentrations of IL-6, IL-1β and TNF-α in healthy dogs of different body sizes and ages were measured to determine whether inflammaging may play a mechanistic role in aging rates in dogs, similar to those found in humans. Using a four-way ANOVA, a significant decrease in IL-6 concentrations in young dogs with the rest of the age categories showing increased IL-6 concentrations was found, similar to humans. However, only young dogs have decreased IL-6 concentrations, with adult dogs having similar IL-6 concentrations to senior and geriatric dogs, implying differences in aging rates between humans and dogs. And, there was a marginally significant interaction between sex*spayed or neutered status and IL-1β concentrations with intact females having the lowest IL-1β concentrations compared with intact males, and spayed and neutered dogs. The presence of estrogen in intact females may, overall, decrease inflammatory pathways. This implies that age at spaying or neutering may be an important aspect to consider for inflammaging pathways in dogs. Furthermore, sterilized dogs often die of immune-related diseases, which could be linked to the increases in IL-1β in sterilized dogs found in this study.

Features of changes in the content of hormones of the hypothalamic-pituitary tract depending on the independent or combined variant of B16/F10 melanoma growth in mice of both sexes

The aim of our research work was to study changes in the level of hormones of the hypothalamus and pituitary gland in mice of both sexes in different variants of the B16/F10 melanoma growth. BALB/c Nude mice (n=84) of both sexes were divided into groups as follows: intact males and females (n=14); a reference group of mice of both sexes with standard subcutaneous B16/F10 melanoma inoculation (n=14); the main group of mice (n=14) where B16/F10 melanoma and Lewis carcinoma were inoculated into the mice sequentially subcutaneously on two sides: one on the left side, the other on the right side. At the terminal stage of the tumor growth, with ELISA using standard kits in 1% hypothalamic tissue homogenates we determined contents of releasing hormones as follows: corticotropic hormone (CRH), thyrotropic hormone (TRH), gonadotropic hormone (GnRH), somatotropic hormone (STH-R); in the pituitary with RIA determined were TSH, LH, FSH and ACTH (Immunotech, Czech Republic). Results. In males and females of both groups, the level of TRH in the hypothalamus decreased by 9-3.7 times, and only in females of the main group, the level of TSH in the pituitary gland increased by 2.8 times. Other releasing peptides in the hypothalamus of females increased by 1.9-6 times, while in males they decreased by 1.4-7 times. In the pituitary gland in males of both groups, the level of LH increased by 1.3-1.4 times and ACTH by 2.5-4 times, but FSH decreased by 7.8-13.6 times. In females, the level of FSH and ACTH in the pituitary gland decreased by 1.5 times – 1.8 times (р˂0.05), only in the main group the content of TSH increased by 2.8 times and only in the reference group LH by 1.6 times (р˂0.05). Conclusion. With the development of B16/F10 melanoma, there was a sex-dependent dysfunction of the hypothalamic-pituitary tract. Changes in the concentrations of GnRH, CRH, and STH-R in the hypothalamus in different directions in males and females indicate different mechanisms of hormonal imbalance in response to the growth of a malignant tumor.