X-Message-Number: 11913
Date: Mon, 7 Jun 1999 03:23:26 -0700 (PDT)
From: Doug Skrecky <>
Subject: cysteine protects against cryoprotectant toxicity

  Karran G.  Legge M.
  Department of Biochemistry, University of Otago, Dunedin, New Zealand.
  Non-enzymatic formation of
  formaldehyde in mouse oocyte freezing mixtures.
  Human Reproduction.  11(12):2681-6, 1996 Dec.
  Three cryoprotectant solvents, dimethylsulphoxide, 1,2-propanediol and
  glycerol, were investigated for a non-enzymatic reaction
  product, formaldehyde. All three cryoprotectants
  demonstrated a direct relationship between increasing solvent molarity and
  increasing formaldehyde concentration which was independent
  of temperature and protein (bovine serum albumin). Medium composition
  significantly influenced the formaldehyde concentration with
  HTF > T6 > M16 = M2. The formaldehyde could be effectively
  removed by reduced glutathione, cysteine and dithiothreitol with cysteine
  being the most effective scavenging agent. A reaction mechanism for this
  scavenging is proposed. The combination of cysteine and cryoprotectant
  reduced the zona pellucida 'hardening' effect in mouse oocytes.

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=11913