X-Message-Number: 24136 Date: Sat, 22 May 2004 21:00:56 -0700 (PDT) From: Doug Skrecky <> Subject: calcium chelation reduces vitrification solution toxicity Mol Reprod Dev. 2004 Jun;68(2):250-8. Lowering intracellular and extracellular calcium contents prevents cytotoxic effects of ethylene glycol-based vitrification solution in unfertilized mouse oocytes. We investigated the characteristics of the changes in intracellular calcium (Ca2+) concentration ([Ca2+](i)) and the viability of the unfertilized mouse oocytes exposed to various concentrations of ethylene glycol (EG)-containing solutions or vitrification solutions. Oocytes exposed to EG (1, 5, 10, 20, and 40% (v/v)) exhibited a rapid and dose-dependent increase in [Ca2+](i). The survival rate was 100% when oocytes were exposed to the EG concentration up to 5% through 5 min, while all oocytes were dead within 3 min when exposed to 10, 20, or 40% EG. When extracellular Ca2+ was removed,increase in [Ca2+](i) at 10 and 20% EG was less than that at the same concentrations of EG with extracellular Ca2+. The survival rates of the oocytes exposed to 10, 20, and 40% EG at 3 min were 100, 97, and 0%, respectively. In the presence of 20 microM 1,2-bis(o-aminopheoxy)ethane-N,N,N',N'-tetraacetic acid tetra acetoxymethyl ester (BAPTA-AM), a Ca2+ chelator, a small increase in [Ca2+](i) exposed to 10, 20, and 40% EG was observed until 4 min. Subsequently prolonged elevation of the [Ca2+](i) was observed in the oocytes exposed to 40% EG but not with 10 and 20% EG. The survival rate of the oocytes, in the presence of 20 microM BAPTA-AM, exposed to 10 and 20% EG was 100% throughout 5 min, while the oocytes exposed to 40% EG were alive only for 3 min. Treatment by the vitrification solution with various concentrations of EG (10, 20, and 40%) caused a smaller increase in [Ca2+](i), while the survival rates were higher compared to those without vitrification solution at the same concentrations of EG. These data suggested that the sustained [Ca2+](i) rises by EG in unfertilized mouse oocytes resulted in cell death. Therefore, the lowering of [Ca2+](i) in the oocytes exposed to the cryoprotectant may improve the viability of cryopreserved unfertilized oocytes. Copyright 2004 Wiley-Liss, Inc. (Below are some other possible pretreatments, which may help block vitrification toxicity.) Methods Find Exp Clin Pharmacol. 2002 Mar;24(2):77-9. Modulatory effect of Cyclea peltata Lam. on stone formation induced by ethylene glycol treatment in rats. The inhibitory effect of the root of Cyclea peltata Lam. on nephrolithiasis induced in rats by feeding with ethylene glycolated water (1%) for 35 days was summarized. Ethylene glycol administration led to oxalate stone formation, as indicated by its high level in urine. Complementary to this anion, the cation calcium level in urine was elevated. These two ions may have contributed to the formation of calcium oxalate stones. In addition to high serum potassium, a low serum magnesium level contributed to stone formation. Simultaneous administration of the powdered root of Cyclea peltata resulted in decreased urinary oxalate and calcium. Likewise, serum potassium was lowered and magnesium was elevated. These observations provided the basis for the conclusion that this plant inhibits the stone formation induced by ethylene glycol treatment. Am J Vet Res. 1994 Dec;55(12):1762-70. Efficacy of 4-methylpyrazole for treatment of ethylene glycol intoxication in dogs. 4-Methylpyrazole (4-MP), an alcohol dehydrogenase inhibitor, was administered to dogs to treat ethylene glycol (EG) intoxication. Eleven dogs were given 10.6 g of EG/kg of body weight; 5 dogs were treated with 4-MP 5 hours after EG ingestion and 6 dogs were treated with 4-MP 8 hours after EG ingestion. 4-Methylpyrazole was administered IV as a 50-mg/ml [corrected] solution in 50% polyethylene glycol: initial dose, 20 mg/kg; at 12 hours after initial dose, 15 mg/kg; at 24 hours after initial dose, 10 mg/kg; and at 30 hours after initial dose, 5 mg/kg. Physical, biochemical, hematologic, blood gas, serum and urine EG concentrations, and urinalysis findings were evaluated at 0, 1, 3, 6, 9, 12, 24, 48, 72 hours, and at 1 week and 2 weeks after EG ingestion. Dogs of both groups developed clinicopathologic signs associated with EG intoxication, including CNS depression, hyperosmolality, high anion gap metabolic acidosis, polydipsia, polyuria, calcium oxalate monohydrate and dihydrate crystalluria, and isosthenuria. Fractional excretion of sodium was increased in all dogs between 1 and 9 hours after EG ingestion, but remained increased beyond 24 hours only in the 2 dogs treated at 8 hours after EG ingestion that developed acute renal failure. All dogs treated 5 hours after EG ingestion recovered without morphologic, biochemical, or clinical evidence of renal impairment. Of the 6 dogs treated 8 hours after EG ingestion, 2 developed acute renal failure. One of the dogs treated 8 hours after EG ingestion remained isosthenuric for 2 months, but did not manifest any other signs of renal impairment.(ABSTRACT TRUNCATED AT 250 WORDS) Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=24136