Preliminary safety study for an equine (Equus caballus) vaccine against sperm acrosome associated 3 protein

In the United States, the wild horse population exceeds the recommended carrying capacity by about 60,000 horses. • Current contraceptive methods include: surgical (removal of ovaries), hormonal (progesterone, GnRH), and immunologic (porcine zona pellucida, GnRH). • SPACA3 is a sperm surface membrane protein involved in sperm-egg plasma membrane adhesion and fusion during fertilization, and has been identified in men, cattle, sheep, and deer. • SPACA3 has also been identified in the granulosa cells and ooplasm in dogs and cats

Possible Relationship between Long-Term Adverse Health Effects of Gonad-Removing Surgical Sterilization and Luteinizing Hormone in Dogs

Spaying and neutering dogs is commonly used to prevent the birth of unwanted animals and eliminate the risk of reproductive diseases. However, removal of the gonads prevents the feedback of estrogen and testosterone on the pituitary and hypothalamus. As a result, luteinizing hormone (LH) is continuously elevated at supraphysiologic concentrations. Although the main role of LH is for reproductive function (e.g., ovulation), there are LH receptors present in several normal tissues including the thyroid and adrenal glands, gastrointestinal tract, cranial cruciate ligament and round ligament, and lymphocytes. In addition, there are LH receptors present in several neoplastic tissues (e.g., lymphoma, hemangiosarcoma, mastocytoma, transitional cell carcinoma, and osteosarcoma). The role of LH receptors in non-reproductive normal and neoplastic tissues is not known but may stimulate nitric oxide release and induce cell division. The precise etiology of the increased incidence of several non-reproductive long-term health complications following spaying and neutering is not known but may be related to LH receptor activation in these non-reproductive target tissues. How these effects may be mediated is described in this review

A novel approach employing ultrasound guidance for percutaneous cardiac muscle injection to retrograde label rat stellate ganglion neurons.

Stellate ganglion (SG) neurons provide the main sympathetic innervation to the heart and help to regulate cardiac function. The purpose of this study was to determine if ultrasound imaging could be employed to retrograde label rat SG neurons innervating the heart without employing thoracotomy. In addition, electrophysiological experiments were performed to characterize the modulation of Ca(2+) channels by neurotransmitters in unlabeled and dye-labeled SG neurons. Fluorescence imaging of actutely isolated cells revealed that dye uptake was successful within five days following injection of dye in the cardiac muscle. Whole-cell voltage-clamp recordings revealed that the majority of the Ca(2+) current was carried by N-type Ca(2+) channels. Finally, fluorescence dye uptake did not appear to affect the modulation of Ca(2+) currents following exposure of SG neurons to norepinephrine, adenosine and neurokinin A. These results demonstrate that ultrasound imaging-guided percutaneous injection can be effectively employed to retrograde label neurons innervating the heart

Comparison of Chemical and Surgical Vasetomy on Testicular Activity in Free-Roaming Horses (Equus caballus)

Free-roaming horse (Equus caballus) management is a complex issue incorporating social, economic, emotional, political, and environmental factors. Currently, few proven field techniques exist for managing free-roaming horse population growth, which can reach 20–25% annually. Although there are several strategies available for sterilizing mares when managing free-roaming horse populations, surgical vasectomy is the only method used in the field for stallions. Some managers believe that surgically vasectomizing dominant stallions would have significant effects on reducing horse populations. However, sterilizing only dominant harem stallions results in a relatively modest reduction in population growth as substantial reproduction may occur even when 100% of the dominant harem stallions are sterilized if other males perform as little as 10% of the breeding. The overall goal of the current project was to evaluate the efficacy of a novel nonsurgical method for sterilizing free-roaming horses (chemical vasectomy). In September of 2013, stallions that had been previously surgically vasectomized (SURG, n¼25), previously chemically vasectomized (CHEM, n¼16), or untreated (CONT, n¼32) were captured and surgically castrated in preparation for adoption. When comparing both sterilization methods to CONT, serum testosterone and estrone sulfate concentrations did not differ (P . 0.05), suggesting that these methods for sterilizing free-roaming stallions would not disrupt herd social hierarchy. However, similar to the CONT, all CHEM stallions had sperm present within the vas deferens seminal fluid samples. CHEM stallions had more morphologically abnormal sperm than did CONT stallions but it is not known if this affected the actual fertility. Additional research is needed using alternative sclerosing agents for chemical vasectomy in free-roaming horse populations.Keywords: stallions, sterilization, testosterone, equid, spermatogenesis, Equus caballu