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Vibratory Stimulation of Ejaculation Yields Increased Motile Spermatozoa, Compared with Electroejaculation, in
Richard R. Yeoman1, Robert B. Ricker, Lawrence E. Williams
1Department of Obstetrics/Gynecology, University of South Alabama, Mobile, AL 36688.
Abstract:
Semen sample collection in squirrel monkeys has traditionally relied on electroejaculation (EE) via the rectum; how- ever, the yield is low when anesthesia is used. An alternative method has been advocated for men with spinal cord injury that relies on penile vibratory afferent stimulation. Vibratory stimulation (VS) physiologically coordinates emission and ejaculation without requiring anesthesia; this procedure was investigated in squirrel monkeys. During the breeding season, 10 donor males were evenly allotted to two groups; one received VS, and the other received EE. Three days later, treatments were reversed. For VS, a clinical unit was adapted to hold a 1.8-ml microcentrifuge tube as an artificial vagina. Unanesthetized, manually restrained animals were positioned in ventral recumbency. Vibratory stimulation consisted of a I-mm amplitude, 75-Hz stimulation for 1 min, rest for 1 min, then continued stimulation at 1.8-mm amplitude, 90 Hz for 1 min. For EE, animals were anesthetized by administration of Telazol(3.5 mg/kg of body weight, IM) and stimulated by EE via the rectum, using a 5- to 7.5-V, 60-Hz sine wave for 1 minute of 1 sec on/ I sec off and a probe with two longitudinal electrodes and a temperature monitor. Stimulation was repeated after 1 minute s rest. Semen samples were diluted, incubated, centrifuged, and evaluated for spermatozoal count and motility. Nine of 10 monkeys responded to VS with semen samples, all of which contained spermatozoa. Mean motility was 79.8% and total mean motile spermatozoa yield was 26.1 (range, 0.4 to 110) million. By use of EE, all monkeys produced semen samples, but only 6 samples contained spermatozoa, with mean motility of 70% and low yield of 0.534 (range, 0.038 to 2.2) million motile spermatozoa. In conclusion, penile VS was superior with regard to quantity of motile spermatozoa obtained. Additionally, no anesthesia was necessary for this relatively benign procedure.
Insights
Penile vibratory stimulation (VS) offers a superior method for collecting squirrel monkey semen compared to electroejaculation (EE). VS yielded significantly more motile sperm without anesthesia, making it a more effective and humane technique for primate research.
Area of Science:
- Primate reproductive physiology
- Animal reproductive technologies
- Non-human primate semen collection
Background:
- Traditional electroejaculation (EE) in squirrel monkeys often yields low semen quality, especially when anesthesia is used.
- Penile vibratory stimulation (VS) is an alternative method that coordinates ejaculation without anesthesia, previously shown effective in humans with spinal cord injury.
Purpose of the Study:
- To investigate the efficacy of penile vibratory stimulation (VS) as an alternative semen collection method in squirrel monkeys.
- To compare the quantity and quality of semen obtained via VS versus traditional electroejaculation (EE).
Main Methods:
- Ten squirrel monkeys were divided into two groups, receiving either VS or EE, with treatments reversed three days later.
- VS involved a 1-minute stimulation cycle with varying amplitude and frequency without anesthesia, while EE required anesthesia (Telazol) and rectal probe stimulation.
- Semen samples were analyzed for spermatozoal count and motility.
Main Results:
- Nine out of ten monkeys successfully produced semen samples via VS, with a mean motility of 79.8% and a mean yield of 26.1 million motile spermatozoa.
- Electroejaculation (EE) resulted in semen samples from all monkeys, but only six contained spermatozoa, with a mean motility of 70% and a significantly lower mean yield of 0.534 million motile spermatozoa.
- VS was found to be superior in terms of the quantity of motile spermatozoa obtained.
Conclusions:
- Penile vibratory stimulation (VS) is a more effective method for collecting squirrel monkey semen than electroejaculation (EE).
- VS provides a higher yield of motile spermatozoa and does not require anesthesia, making it a more benign and efficient procedure for primate research.