1月30日，《生殖生物学和内分泌》（Reproductive Biology and Endocrinology）上发表最新研究成果称，美国北卡罗来纳大学科学家发现向睾丸发射一次超声波可能导致精子暂时停止生产。在实验鼠身上实施的实验结果表明，声波能够导致精子数量减少。因此科学家认为，这种方式有可能导致人类的暂时不育，这也将是一种新型避孕方法。
研究人员把超声波看作是“一种有前途的避孕备选方案”，不过他们也承认，在真正投入临床应用前，这种方法还需要更多的试验。其实，这种方案最早提出于上世纪70年代，现在只是由美国北卡罗来纳大学研究人员再次提出并得出了具体的实验结果。
在实验中，研究人员发现，两次15分钟的超声波可以有效地减少精子细胞的数量。科学家解释说，对于人类来说，当精子浓度下降到每毫升1500万个精子时，就可被认为是处于“亚生育能力状态”。实验中的老鼠精子浓度被减少到每毫升1000万个。
此项研究首席科学家詹姆斯-特苏鲁塔表示，“接下来的研究需要证明，这种避孕效果能够持续多长时间，以及多次使用是否安全。”研究团队需要明确超声波是否会产生副作用，否则就有可能因为避孕而导致绝育。多次使用超声波是否会对人身造成积累性损害，这也是研究人员需要解决的问题。
英国谢菲尔德大学男科学博士阿伦-帕塞认为，“这是一个好主意，但是还有很多工作需要做。使用这种方法以后，精子生产有可能会恢复，但是精子有可能会受到损害。精子恢复生产，出生的婴儿仍有可能受到损害。我们所担心的最后一个问题是，这种方法可能会对精子造成长久性的损伤。”(生物谷 Bioon.com)
doi:10.1186/1477-7827-10-7
PMC:
PMID:
Therapeutic ultrasound as a potential male contraceptive: power, frequency and temperature required to deplete rat testes of meiotic cells and epididymides of sperm determined using a commercially available system
James K Tsuruta, Paul A Dayton, Caterina M Gallippi, Michael G O'Rand, Michael A Streicker, Ryan C Gessner, Thomas S Gregory, Erick JR Silva, Katherine G Hamil, Glenda J Moser and David C Sokal
Background
Studies published in the 1970s by Mostafa S. Fahim and colleagues showed that a short treatment with ultrasound caused the depletion of germ cells and infertility. The goal of the current study was to determine if a commercially available therapeutic ultrasound generator and transducer could be used as the basis for a male contraceptive.
Methods
Sprague-Dawley rats were anesthetized and their testes were treated with 1 MHz or 3 MHz ultrasound while varying power, duration and temperature of treatment.
Results
We found that 3 MHz ultrasound delivered with 2.2 Watt per square cm power for fifteen minutes was necessary to deplete spermatocytes and spermatids from the testis and that this treatment significantly reduced epididymal sperm reserves. 3 MHz ultrasound treatment reduced total epididymal sperm count 10-fold lower than the wet-heat control and decreased motile sperm counts 1,000-fold lower than wet-heat alone. The current treatment regimen provided nominally more energy to the treatment chamber than Fahim's originally reported conditions of 1 MHz ultrasound delivered at 1 Watt per square cm for ten minutes. However, the true spatial average intensity, effective radiating area and power output of the transducers used by Fahim were not reported, making a direct comparison impossible. We found that germ cell depletion was most uniform and effective when we rotated the therapeutic transducer to mitigate non-uniformity of the beam field. The lowest sperm count was achieved when the coupling medium (3% saline) was held at 37 degrees C and two consecutive 15-minute treatments of 3 MHz ultrasound at 2.2 Watt per square cm were separated by 2 days.
Conclusions
The non-invasive nature of ultrasound and its efficacy in reducing sperm count make therapeutic ultrasound a promising candidate for a male contraceptive. However, further studies must be conducted to confirm its efficacy in providing a contraceptive effect, to test the result of repeated use, to verify that the contraceptive effect is reversible and to demonstrate that there are no detrimental, long-term effects from using ultrasound as a method of male contraception.
