Sperm crawl and collide on way to egg, researchers say

May 7, 2012

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 (PNAS) provide fresh insight into how might find their way to the egg that will help to inform future innovation in the struggle to treat .

Scientists led by Dr Petr Denissenko, of the School of Engineering at the University of Warwick, and Dr Jackson Kirkman-Brown, lead in at the University of Birmingham, explored what properties distinguish the tens of cells which make it to the egg from the millions of 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?
"In basic terms – how do we find the 'Usain Bolt' among the millions of sperm in an ejaculate. Through research like this we are learning how the good sperm navigate by sending them through mini-mazes. "

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 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.

Explore further: Mitochondrial respiratory capacity, sperm motility linked

More information: Human sperm swimming in micro-channels, Proceedings of the National Academy of Sciences (2012).

Related Stories

Mitochondrial respiratory capacity, sperm motility linked

April 10, 2012
(HealthDay) -- Sperm with higher motility have increased mitochondrial respiratory capacity, according to a study published in the April issue of Urology.

Men with deep voice may be lacking in sperm: study

January 9, 2012
(Medical Xpress) -- Women look for tall, dark and handsome. Those chiseled features and that deep sexy voice have gained the attention of women for generations. However, a new study published in PLoS ONE shows that those ...

Recommended for you

Drug found that induces apoptosis in myofibroblasts reducing fibrosis in scleroderma

December 15, 2017
(Medical Xpress)—An international team of researchers has found that the drug navitoclax can induce apoptosis (self-destruction) in myofibroblasts in mice, reducing the spread of fibrosis in scleroderma. In their paper ...

How defeating THOR could bring a hammer down on cancer

December 14, 2017
It turns out Thor, the Norse god of thunder and the Marvel superhero, has special powers when it comes to cancer too.

Researchers track muscle stem cell dynamics in response to injury and aging

December 14, 2017
A new study led by researchers at Sanford Burnham Prebys Medical Discovery Institute (SBP) describes the biology behind why muscle stem cells respond differently to aging or injury. The findings, published in Cell Stem Cell, ...

'Human chronobiome' study informs timing of drug delivery, precision medicine approaches

December 13, 2017
Symptoms and efficacy of medications—and indeed, many aspects of the human body itself—vary by time of day. Physicians tell patients to take their statins at bedtime because the related liver enzymes are more active during ...

Study confirms link between the number of older brothers and increased odds of being homosexual

December 12, 2017
Groundbreaking research led by a team from Brock University has further confirmed that sexual orientation for men is likely determined in the womb.

Potassium is critical to circadian rhythms in human red blood cells

December 12, 2017
An innovative new study from the University of Surrey and Cambridge's MRC Laboratory of Molecular Biology, published in the prestigious journal Nature Communications, has uncovered the secrets of the circadian rhythms in ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Hev
not rated yet May 08, 2012
typical male behaviour -

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.