Sperm crawl and collide on way to egg, researchers say
Scientists at the Universities of Birmingham and Warwick have shed new light on how sperm navigate the female reproductive tract, 'crawling' along the channel walls and swimming around corners; with frequent collisions.
Research results published today in the Proceedings of the National Academy of Sciences (PNAS) provide fresh insight into how sperm might find their way to the egg that will help to inform future innovation in the struggle to treat infertile couples.
Scientists led by Dr Petr Denissenko, of the School of Engineering at the University of Warwick, and Dr Jackson Kirkman-Brown, lead in reproductive biology at the University of Birmingham, explored what properties distinguish the tens of cells which make it to the egg from the millions of sperm cells ejaculated.
Contrary to popular belief, the authors report, sperm rarely swim in the central part of the three-dimensional female tract, instead travelling along the walls, meaning in the body they are negotiating complex and convoluted channels filled with viscous fluids.
To study cell behaviour in confined space, cells were injected into hair-thin microchannels.
"When the channel turns sharply, cells leave the corner, continuing ahead until hitting the opposite wall of the channel, with a distribution of departure angles, the latter being modulated by fluid viscosity," the reports' authors said.
"Specific wall shapes are able to preferentially direct motile cells," the authors report.
"As a consequence of swimming along the corners, the domain occupied by cells becomes essentially one-dimensional.
"This leads to frequent collisions and needs to be accounted for when modelling the behaviour of populations of migratory cells."
Dr Kirkman-Brown, who is also Science Lead for the Birmingham Women's Fertility Centre, comments: "Two key questions in reproduction are:
- how are the millions of sperm selected down to around ten that reach the oocyte?: and
- Can we use a similar method to select sperm for fertility treatments?
Dr Denissenko of the University of Warwick added: "Sperm cell following walls is one of those cases when a complicated physiological system obeys very simple mechanical rules.
"I study fluids in a variety of environments, but moving to work with live human sperm was quite a change.
"I couldn't resist a laugh the first time I saw sperm cells persistently swerving on tight turns and crashing head-on into the opposite wall of a micro-channel.
"More seriously, it's great being part of an internationally leading team based out of the Midlands addressing a key problem."
Dr Kirkman-Brown concludes: "Previous research from the group indicates that the shape of the sperm head can subtly affect how the sperm swim.
"Combined with this data we believe new methods of selecting sperm, perhaps for quality or even in certain non-human species for sex may become possible."
The researchers suggest that the combined effect of the fluid rheology and three-dimensional architecture should be taken into account in future in-vitro studies.
More information: Human sperm swimming in micro-channels, Proceedings of the National Academy of Sciences (2012).
Journal reference: Proceedings of the National Academy of Sciences
Provided by University of Warwick
- Rodent sperm work together for better results Jan 24, 2007 | not rated yet | 0
- Sperm can count Mar 07, 2012 | not rated yet | 0
- Viagra could be harmful to fertility Feb 25, 2008 | not rated yet | 0
- Mitochondrial respiratory capacity, sperm motility linked Apr 10, 2012 | not rated yet | 0
- New Sperm shaker set to improve IVF success rates Jan 19, 2009 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Why is zone 1 in liver more prone to ischemic injury?
17 hours ago Hi, Is it because around central vein, there is only deoxygenated blood from the vein where as in the periphery there is hepatic artery. Also why...
How can there be villous adenoma in colon, if there are no villi there
May 22, 2013 As title suggest. Thanks :smile:
How can there be a term called "intestinal metaplasia" of stomach
May 21, 2013 Hello everyone, Ok Stomach's normal epithelium is simple columnar, now in intestinal type of adenocarcinoma of stomach it undergoes "intestinal...
Pressure-volume curve: Elastic Recoil Pressure don't make sense
May 18, 2013 From pressure-volume curve of the lung and chest wall (attached photo), I don't understand why would the elastic recoil pressure of the lung is...
If you became brain-dead, would you want them to pull the plug?
May 17, 2013 I'd want the rest of me to stay alive. Sure it's a lousy way to live but it beats being all-the-way dead. Maybe if I make it 20 years they'll...
MRI bill question
May 15, 2013 Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not...
- More from Physics Forums - Medical Sciences
More news stories
By discovering the new mechanism by which estrogen suppresses lipid synthesis in the liver, UC Irvine endocrinologists have revealed a potential new approach toward treating certain liver diseases.
Medical research 5 hours ago | not rated yet | 0 |
Aortic arch pulse wave velocity, a measure of arterial stiffness, is a strong independent predictor of disease of the vessels that supply blood to the brain, according to a new study published in the June issue the journal ...
Medical research 5 hours ago | not rated yet | 0
Since the discovery of Prontosil in 1932, sulfonamide antibiotics have been used to combat a wide spectrum of bacterial infections, from acne to chlamydia and pneumonia. However, their side effects can include serious neurological ...
Medical research 7 hours ago | not rated yet | 0 |
Scientists at the National Institutes of Health report they have discovered in mouse studies that a small molecule released in the spinal cord triggers a process that is later experienced in the brain as ...
Medical research 7 hours ago | 5 / 5 (2) | 0 |
Spanish researchers have discovered that the daily clearance of neutrophils from the body stimulates the release of hematopoietic stem cells from the bone marrow into the bloodstream, according to a report published today ...
Medical research 8 hours ago | 5 / 5 (2) | 0
(HealthDay)—Type 2 diabetes is more aggressive in children than adults, with signs of serious complications seen just a few years after diagnosis, new research finds.
42 minutes ago | not rated yet | 0
(Medical Xpress)—Regulating the distribution of power in neurons is done by a system that makes the national electric grid look simple by comparison. Each neuron has several thousand mitochondria confined ...
3 hours ago | 4.7 / 5 (3) | 0 |
Teams of highly respected Alzheimer's researchers failed to replicate what appeared to be breakthrough results for the treatment of this brain disease when they were published last year in the journal Science.
7 hours ago | 5 / 5 (1) | 1 |
A brief visual task can predict IQ, according to a new study. This surprisingly simple exercise measures the brain's unconscious ability to filter out visual movement. The study shows that individuals whose ...
9 hours ago | 4.9 / 5 (7) | 0 |
Little is known about why asthma develops, how it constricts the airway or why response to treatments varies between patients. Now, a team of researchers at Weill Cornell Medical College, Columbia University Medical Center ...
7 hours ago | not rated yet | 0 |
Ethnic background plays a surprisingly large role in how diabetes develops on a cellular level, according to two new studies led by researchers at the Stanford University School of Medicine.
5 hours ago | not rated yet | 0 |