Effect of testicular degeneration on expression of sperm protein at 22 kDa in stallions

BACKGROUND

Sperm protein at 22 kDa has been associated with fertility.

OBJECTIVES

The objectives of this study were to determine (1) the localization pattern of SP22 on ejaculated and caudal epididymal equine spermatozoa and in epididymal fluid, and to (2) characterize SP22 protein and mRNA expression in testicular and epididymal tissues in response to heat-induced testicular degeneration.

MATERIALS AND METHODS

Semen was collected before and after hemi-castration, as well as prior to and following insulation of the remaining testes, and tissue specimens were collected for analysis.

RESULTS

Histopathology confirmed degeneration in insulated testes. Ejaculated and epididymal spermatozoa from samples collected prior to insulation of the testicles had a predominant staining pattern of SP22 over the equatorial region. However, the equatorial pattern in the pre-insulation epididymal semen samples was significantly lower than in the pre-insulation ejaculated semen samples (68 ± 3, 81 ± 2.6, respectively). Ejaculated and epididymal samples collected after insulation of the testicles showed a complete loss of staining as the predominant pattern. Western blot analysis verified the presence of SP22 on fresh ejaculated spermatozoa prior to and following heat-induced degeneration, on epididymal spermatozoa after testicular insulation, and in testicular and epididymal tissues. Heat insulation significantly reduced messenger RNA expression in the head of the epididymis and testicular tissues. Immunohistochemistry of the testicular and epididymal tissues pre-heating showed considerably weaker staining than the same tissues post-heating.

DISCUSSION AND CONCLUSION

It was concluded that heat-induced testicular damage causes both loss and relocation of SP22 on the sperm membrane. Future studies are warranted to determine the diagnostic value of these findings.

A multifaceted analytical approach for detecting effects on semen quality when using small sample sizes

Driven by technical, logistical and economic limitations, detection of treatment effects on semen quality typically include the design and collection of small sample datasets. A consequence of these small sample studies is that they suffer low statistical power. Historically, researchers faced with small sample size studies have relied upon non-parametric analysis; however, this approach is still unlikely to tease out a true statistical significance based upon limited sample size. Here we propose a novel methodology that can be applied in small samples study situations that combines repeated measures ANOVA and Mixed-Effects linear regression models with Bayesian Linear regression modeling when evaluating for treatment effects on quantitative semen quality parameters. Using this methodology, we show that investigating the data with this multifaceted analytical technique results in improved reproducibility and sensitivity of the findings while minimizing the likelihood of Type 1 errors when combining the inference statistics from multiple models/methodologies using Bayes Factor analysis.

The effect of select seminal plasma proteins on endometrial mRNA cytokine expression in mares susceptible to persistent mating-induced endometritis

In the horse, breeding induces a transient endometrial inflammation. A subset of mares are unable to resolve this inflammation, and they are considered susceptible to persistent mating-induced endometritis PMIE Select seminal plasma proteins cysteine-rich secretory protein-3 (CRISP-3) and lactoferrin have been shown to affect the innate immune response to sperm in vitro. The objective of this study was to determine whether the addition of CRISP-3 and lactoferrin at the time of insemination had an effect on the mRNA expression of endometrial cytokines in susceptible mares after breeding. Six mares classified as susceptible to PMIE were inseminated during four consecutive oestrous cycles with treatments in randomized order of: 1 mg/ml CRISP-3, 150 μg/ml lactoferrin, seminal plasma (positive control) or lactated Ringer's solution (LRS; negative control) to a total volume of 10 ml combined with 1 × 10⁹ spermatozoa pooled from two stallions. Six hours after treatment, an endometrial biopsy was obtained for qPCR analysis of selected genes associated with inflammation (pro-inflammatory cytokines interleukin (IL)-1β, IL-8, tumour necrosis factor (TNF)-α, interferon (INF)-γ, anti-inflammatory cytokines IL-1RN and IL-10, and inflammatory-modulating cytokine IL-6). Seminal plasma treatment increased the mRNA expression of IL-1β (p = .019) and IL-8 (p = .0068), while suppressing the mRNA expression of TNF (p = .0013). Lactoferrin also suppressed the mRNA expression of TNF (p = .0013). In conclusion, exogenous lactoferrin may be considered as one modulator of the complex series of events resulting in the poorly regulated pro-inflammatory response seen in susceptible mares.

The effect of treatment with immune modulators on endometrial cytokine expression in mares susceptible to persistent breeding-induced endometritis

REASONS FOR PERFORMING STUDY

Research has shown that 6 h after breeding is a critical time during the uterine innate immune response, and the failure to respond appropriately will result in persistent breeding-induced endometritis. This presents a potential opportunity to modulate the course of inflammation towards a timely resolution.

OBJECTIVES

To evaluate the effects of immune modulation on endometrial mRNA expression of inflammatory genes in susceptible mares 6 h after breeding. The hypothesis was that immune modulation alters endometrial cytokine expression in susceptible mares.

STUDY DESIGN

A randomised controlled study to evaluate the effects of mycobacterial cell wall extract and dexamethasone on endometrial gene expression after insemination in 6 mares susceptible to persistent breeding-induced endometritis.

METHODS

Six susceptible mares were selected based on their uterine inflammatory response to insemination. Mares were inseminated during 3 oestrous cycles with 1 × 10(9) nonviable spermatozoa and 1) no additional treatment (control), or in combination with 2) dexamethasone (50 mg i.v.) at the time of insemination, or 3) with mycobacterial cell wall extract (1.5 ml i.v.) administered 24 h prior to insemination. Mares received one treatment per cycle in randomised order, and each mare served as her own control. Endometrial biopsies were collected 6 h after breeding, and quantitative polymerase chain reaction analysis for interleukin (IL)1β, IL6, interferon γ, IL10 and IL1RA was performed. Relative quantification values reported fold changes in mRNA expression from the control. Data were analysed using an ANOVA and significance was set at P<0.05.

RESULTS

Expression of IL1β mRNA was lower after treatment with dexamethasone (P<0.001) and mycobacterial cell wall extract (P<0.05) when compared with control. No differences were detected in the mRNA expression of the other cytokines after any of the treatments.

CONCLUSIONS

Treatment with immune modulators alters endometrial mRNA expression of IL1β after insemination. A better understanding of the mechanisms of immune modulation in the equine uterus can help to improve treatments for persistent breeding-induced endometritis.

Blue light from individual light masks directed at a single eye advances the breeding season in mares

REASONS FOR PERFORMING STUDY

Artificial lighting is commonly used to advance the breeding season in horses. Light masks have been developed that direct light at a single eye to inhibit the production of melatonin, the decoder of photoperiod for seasonally breeding animals.

OBJECTIVES

To investigate whether low-intensity blue light from light masks was effective at advancing the breeding season in mares.

STUDY DESIGN

Controlled experiment.

METHODS

Data on reproductive activity was collected from 3 groups of mares maintained on Kentucky horse farms under various lighting conditions between 20 November 2011 and 10 February 2012: 59 nonpregnant, healthy Thoroughbred mares were used. On 1 December 2011, Group 1 (n = 16) was housed indoors under barn lighting (250 Lux) until 23.00 h daily. Group 2 (n = 25) wore light masks programmed to turn on from 16.30 h until 23.00 h daily and was maintained outdoors. Group 3 (n = 19) was maintained outdoors under the natural photoperiod as control. At 2-week intervals, rectal ultrasound examinations were performed and blood was collected for progesterone analysis. Oestrous cyclicity was defined as the presence of follicles >20 mm diameter detected in conjunction with serum progesterone >1 ng/ml and confirmation of ovulation by transrectal ultrasound examination.

RESULTS

On 10 February, the number of mares exhibiting oestrous cyclicity was 14/16 (87.5%) in Group 1; 20/25 (80%) in Group 2; and 4/19 (21%), in Group 3. Pairwise comparison of groups revealed no difference in the number of cycling mares between Groups 1 and 2 (χ(2) test, P = 0.3348) whereas differences were observed between Groups 1 and 3 (χ(2) test, P<0.0001) and Groups 2 and 3 (χ(2) test, P<0.0003).

CONCLUSIONS

Low-intensity blue light to a single eye from a light mask is an effective alternative to maintenance of mares indoors under lights for advancing the breeding season. Mobile light therapy for horses could have economic benefits for the breeder by reducing the costs of maintaining mares indoors, and welfare benefits for horses by permitting outdoor maintenance.

Endometrial inflammatory markers of the early immune response in mares susceptible or resistant to persistent breeding-induced endometritis

Transient endometritis after breeding is necessary for clearance of bacteria and spermatozoa; however, in a subpopulation of mares, the inflammation fails to resolve in a timely fashion. The objective of this study was to describe the uterine inflammatory response in mares susceptible or resistant to persistent breeding-induced endometritis (PBIE) during the first 24 h after induction of uterine inflammation.Twelve mares were classified as susceptible (nZ6) or resistant (nZ6) to PBIE. Mares were inseminated over five estrous cycles and endometrial biopsies were collected at one time point per cycle before (0) and 2, 6, 12, and 24 h after insemination. qPCR analysis for IL1B, IL6, IL8, IFNG, TNF (TNFA), IL10, and IL1RN was performed, and endometrial inflammatory cells were counted for each sample. Relative quantification values reported fold changes in mRNA expression from 0 h values. A general pattern of expression post insemination was observed in both groups of mares. Cytokine mRNA increased at 2 h, peaked between 2 and 12 h, and then decreased.Differences were detected between groups of mares 6 h after challenge; resistant mares had higher mRNA expression of IL6, IL1RN,and IL10 than susceptible mares. Susceptible mares had an increased number of polymorphonuclear neutrophils in the endometrium 2 and 12 h after breeding when compared with resistant mares. These findings describe an inherent difference in the initial immune response to insemination and may help explain the transient nature of inflammation in resistant mares, whereas susceptible mares develop a persistent inflammation.

Susceptibility to persistent breeding-induced endometritis in the mare: relationship to endometrial biopsy score and age, and variations between seasons

The objectives were to: (1) investigate the associations of age and endometrial biopsy score with uterine fluid retention after insemination; and (2) determine if a strict classification of susceptibility to persistent breeding-induced endometritis (PBIE) based on biopsy score, endometrial cytology, and fluid retention after inseminations, is consistent over subsequent breeding seasons. In Experiment 1, 57 mares were inseminated with 10(9) freeze-killed sperm during estrus and evaluated for uterine fluid retention 48 h and 96 h after insemination. Comparisons were made between fluid retention and biopsy score or age. In Experiment 2, a subset of 14 mares was classified for susceptibility to persistent breeding-induced endometritis in two subsequent breeding seasons. Biopsy score and age were associated with fluid retention (P < 0.001). In addition, age was related to biopsy score (P < 0.001). Of the mares examined for susceptibility, 36% (5 of 14) changed status during subsequent seasons. Three mares changed to a more severe classification (intermediate to susceptible, or resistant to intermediate), whereas two mares changed to a less severe classification (susceptible to intermediate).

Gender differences in flashbulb memories elicited by the Clarence Thomas hearings

American students and other adults aged 19-75 completed a questionnaire about flashbulb memories and recollections of autobiographical events elicited by the Senate hearings for confirmation of Clarence Thomas as a Supreme Court Justice. The respondents were less likely to recall vivid image memories than were respondents in earlier studies about memories of the assassinations of John Kennedy, Robert Kennedy, and Martin Luther King. Women were significantly more likely than men to report vivid image memories and recall of autobiographical events elicited by the hearings, but they did not differ significantly from men in the ratings of these memories. Women were also significantly more likely than men to report specific memories of having been victims of sexual harassment and abuse. Women recalled reconsidering incidents in which they might have been victims of sexual harassment more often than men did. Exposure to media coverage did not differ by gender, although the amount of coverage paid attention to did correlate with the number of personal memories elicited.