From: Anders Sandberg (asa@nada.kth.se)
Date: Thu Jan 24 2002 - 03:06:13 MST
An interesting little paper in Nature:
Cryopreservation: Fertility after intact ovary transplantation
Nature 415, 385 (2002)
XIANG WANG*, HUIFANG CHEN*, HANG YIN†, S. SAMUEL KIM‡, SEANG LIN TAN†
& ROGER G. GOSDEN†
They transplanted ovaries from rats:
"We used eight fresh organs for transplantation and also seven
treated ones that we had perfused for 30 min at 0.35 ml min-1 with M2
medium containing 0.1 M fructose and increasing concentrations of
dimethylsulphoxide (0-1.5 M). Following a protocol previously used
for sliced ovarian tissue4, we cooled the treated organs slowly in
5-ml cryovials (Nalgene), inducing ice nucleation at -7 °C in the
modified chamber of an automated freezer (CryoLogic). After overnight
storage in liquid nitrogen, we rapidly thawed the vials and removed
the cryoprotectant by perfusion with a reversed concentration
gradient (for further details, see supplementary information)."
"All animals with fresh transplants reinitiated oestrus. They had
normal numbers of ovarian follicles, including graafian stages (Fig.
1a), and uterine weights and FSH levels were similar to those of
controls (9.7 0.5 and 9.1 0.4 ng ml-1, respectively). Four animals
with cryopreserved grafts (57%) had follicular ovaries, and their
corpora lutea indicated recent ovulation (Fig. 1b). One animal was
pregnant, with two healthy fetuses implanted on either side of the
uterine anastomosis (Fig. 1c). This group had higher serum FSH levels
(21.3 6.2 ng ml-1), fewer follicles and lower oestradiol levels and
uterine weights, but none was in the castrate range. Tubal and
uterine morphology were indistinguishable from unoperated controls."
"These results are encouraging, but indicate that ovarian function is
compromised to some extent by freezing, perhaps because of
intravascular ice formation - a problem that has previously
frustrated attempts to cryopreserve kidneys5. Advances in
vitrification may overcome this problem if the chemical toxicity of
additives can be minimized6. Frozen banking of reproductive organs
could eventually be useful in breeding from endangered species and as
a fertility option for women and children who have undergone
sterilizing chemotherapy7, 8. Our success with ovarian transplants
should stimulate investigation into the improvement of
cryopreservation techniques for other organs."
OK, hardly cryonics heaven, but a small step forward. I guess it is
not that impressive since rat ovaries aren't that large and hence
easier to freeze.
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! asa@nada.kth.se http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y
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