 Two
Studies Examining Selenium With Respect to Sperm Motility:
Introduction:
Several research projects are
under way at SRMS regarding the effects of selenium
on human sperm. The focus of these studies has been
to determine if selenium can be added to sperm preparations
to increase motility (movement) and forward progression
(forward movement) of the sperm. The ability to enhance
these two parameters would greatly increase the number
of quality sperm available for insemination and various
Assisted Reproductive Technologies (ART) procedures.
Abstract:
Effect Of In Vitro Supplementation
Of Selenium On Human Sperm Survival And Motility
Characteristics
Andrew Bhatnager, Ph.D.,
Corey Burke, B.S., C.L.S., Alisa Santiago, Craig
R. Sweet, M.D. (4/2008)
Selenium deficiency has been associated with several
reproductive dysfunctions including impaired sperm
motility and several morphological changes in sperm
structure. This research set forth to evaluate the
effects of in vitro supplementation of selenium
on the motility of fresh human sperm. Freshly ejaculated
washed human spermatozoa were exposed to numerous
dosages of selenocysteine ranging from 5?g/mL to
20?g/mL through in vitro supplementation. The sperm
motility, defined as sperm movement, and progression,
defined as the quality of the movement, was evaluated
using computer assisted semen analysis (CASA). The
results yielded that the control sperm maintained
a higher motility and progression rate over a longer
period then all of the selenium treated sperm. The
selenium treated sperm did show an increase in motility
and progression that the control did not at different
times of incubation. The results from this study
were inclusive in determining any distinct influences
of selenocysteine on in vitro human sperm function.
More detailed studies, using an adjusted and wider
range of selenium dosages, are needed to investigate
the role of selenocysteine on in vitro sperm survival.
Further studies would be beneficial to establish
in vitro effects of biologically compatible forms
of selenium on sperm survival. This would have tremendous
clinical implications in improving post-thaw sperm
survival and function.
Dr. Sweet’s Comments:
We are constantly looking
for techniques that will improve the ability of
the sperm to fertilize. Selenium is the substance
under consideration in this paper. In this preliminary
study, one of the problems was that the sperm was
so healthy; it was difficult to find any differences
between the control and the selenium-exposed sperm.
Second, we were uncertain as to how much selenium
to use and we possibly used too much. A few sperm
gave their lives up for this research…
Abstract:
Effects of In Vitro
Selenium Supplementation on Motility of Human Sperm
Andrew Bhatnager, Ph.D.,
Corey Burke, B.S., C.L.S., Craig R. Sweet, M.D.,
Jacqueline Tovar (11/2007)
Assisted Reproductive Technologies (ART) routinely
encounter sperm cells exhibiting reduced motility
due to male factor subfertility or poor post-thaw
sperm survival, resulting in decreased fertilization
potential. Novel methods of enhancing or maintaining
motility have implications in improving the success
rates of ART.
Several substances have been routinely used in clinical
In Vitro Fertilization (IVF) to enhance human sperm
function, including peritoneal fluid, follicular
fluid, progesterone, adenosine analogs, and methylxanthines
such as caffeine and pentoxifylline. Recently, in
vitro selenium supplementation studies have shown
improved human sperm motility. Sporadic studies
using in vitro supplementation of spermatozoa with
selenium have also been reported to enhance motility
in bovine spermatozoa.
The objective of this study was to examine the effects
of in vitro supplementation on human sperm motility.
Sperm were isolated from seminal plasma using a
concentration gradient. The sperm were then incubated
in varying concentrations of selenium ranging from
0.2ug/mL to 20 ug/mL. Computer Assisted Semen Analysis
(CASA) was used to evaluate the sperm motility at
baseline and at various intervals up to 72 hours.
Results at 48 hours showed the greatest gain or
retention of motility in selenium-exposed specimens
vs. the control without supplementation. At 48 hours,
specimens supplemented with 1.2 ug/mL revealed a
motility of 46%. In a similar manner, specimens
supplemented with 1.6 ug/mL show a motility of 48%.
The unexposed control had a motility of only 32%
at 48 hours. Beyond 48 hours, supplementation appeared
to be detrimental to sperm motility in all concentrations.
The data suggest that up to 48 hours of incubation
in selenium supplemented media may preserve or augment
sperm motility in human sperm.
Dr. Sweet’s Comments:
In this study, the laboratory
methodically examined differing concentrations of
selenium to see what the optimal concentration would
be to improve sperm movement. It would appear that
we found a more ideal concentration although the
effects were only obvious at 48 hours. After that,
the selenium may have had a detrimental role in
sperm survival. This study provided more information
but was still somewhat preliminary. A great deal
more work needs to be done before we can propose
that selenium might be of some clinical use but
this was a good start.
Introduction:
There are two basic techniques for cryropreserving
embryos. The first involves a “slow freeze”
process while a second technique uses a more rapid
technique called vitrification. There is published
data suggesting that vitrification may be better with
regards to embryo survival and implantation. This
study was designed to compare the two procedures.
Abstract:
Comparing Cryopreservation
Methods Using Mouse Embryos
Jeremy McGuire, Andrew Bhatnagar, Ph.D. (4/2007)
Innovations in cryopreservation methods have led
to successful cryopreservation of human oocytes
and embryos. The present study was designed to compare
efficacy of two cryopreservation techniques, the
conventional “slow freeze” method and
a new ultra rapid method of “vitrification”.
Previously frozen 2-cell outbred strain of mouse
embryos (BDF X CF1) were thawed and cultured in
vitro in KSOM media for 24 hours to the 6-8 cell
stage and then cryopreserved using 1,2-propanediol
(PROH) as a cryoprotectant for the slow freeze method
and ethylene glycol /dimethyl sulfoxide (EG/DMSO)
for vitrification. Preliminary results suggest that
vitrified embryos exhibited a higher post-thaw survival
rate (100%) and improved blastocyst formation rate
(88%) compared with the slow freeze method (71%
% 59% respectively). Further experiments are in
progress to statically confirm these results and
to evaluate effectiveness of vitrification over
current slow freeze methods for cryopreservation
of human gametes and embryos in clinical IVF laboratories.
Dr. Sweet’s Comments:
This was our first study
using vitrification. The data was intreaging although
not conclusive. Published data regarding human embryos
seems to also be leaning towards vitrification as
a technique that improves the survival rates of
cryopreserved-thawed embryos. The next study we
have proposed involves human oocytes, a much more
difficult cell to freeze, wherein we intend to compare
two different storage containers with respect to
embryologist satisfaction, survival and implantation
rates. Stay tuned! |
