The comparison between the original red blood cell (RBC) Pig-a assay, which measures Pig-a mutant RBCs, and the PIGRET assay, which uses reticulocytes, was conducted using in vivo mutagenesis by ethyl methanesulfonate (EMS) as a part of a collaborative study by the Mammalian Mutagenicity Study Group in the Japanese Environmental Mutagen Society. Three dose levels of EMS (180, 360, and 720mg/kg) were administered once by oral gavage to 8-week-old male Crl:CD(SD) rats, and peripheral blood was sampled at 0 (1 day before dosing), 1, 2, and 4 weeks after dosing with EMS. As a result, a statistically significant increase in the mutant frequency of the Pig-a gene was observed from 2 weeks after dosing and a higher value was obtained on week 4 at the highest dose only in the RBC Pig-a assay. In the PIGRET assay, on the other hand, a statistically significant increase in Pig-a mutant frequency was obtained at the highest dose from 1 week after dosing, and it decreased on weeks 2 and 4 compared to the value at week 1. The Pig-a mutant frequency appeared to reach a plateau 1 week after dosing in the PIGRET assay and it might continue to increase even after week 4 in the RBC Pig-a assay. These results indicate that the PIGRET assay can detect Pig-a mutants much earlier than the original RBC Pig-a assay, and it can enable judgement of mutagenicity of EMS within 1 week after a single dosing.

中文翻译：

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PIGRET 检测可以比 RBC Pig-a 检测更早地检测出甲磺酸乙酯的致突变性。

原始红细胞 (RBC) Pig-a 测定法（测量 Pig-a 突变型红细胞）与使用网织红细胞的 PIGRET 测定法之间的比较是使用甲磺酸乙酯 (EMS) 的体内诱变作为一部分日本环境诱变剂协会哺乳动物致突变性研究组的合作研究。将三种剂量水平的 EMS（180、360 和 720mg/kg）通过灌胃方式给予 8 周龄雄性 Crl:CD(SD) 大鼠一次，并在 0（给药前 1 天）采集外周血， EMS 给药后 1、2 和 4 周。结果，在给药后 2 周观察到 Pig-a 基因突变频率的统计学显着增加，并且仅在 RBC Pig-a 测定中以最高剂量在第 4 周获得更高值。另一方面，在 PIGRET 试验中，从给药后 1 周开始，在最高剂量下，Pig-a 突变频率在统计学上显着增加，与第 1 周的值相比，在第 2 周和第 4 周下降。Pig-a 突变频率似乎达到了平台 1在 PIGRET 试验中给药后一周，即使在 RBC Pig-a 试验中第 4 周后，它也可能继续增加。这些结果表明，PIGRET 检测可以比原来的 RBC Pig-a 检测更早地检测到 Pig-a 突变体，并且可以在单次给药后 1 周内判断 EMS 的致突变性。在 PIGRET 试验中，Pig-a 突变频率似乎在给药 1 周后达到平台期，并且在 RBC Pig-a 试验中甚至在第 4 周后它可能继续增加。这些结果表明，PIGRET 检测可以比原来的 RBC Pig-a 检测更早地检测到 Pig-a 突变体，并且可以在单次给药后 1 周内判断 EMS 的致突变性。在 PIGRET 试验中，Pig-a 突变频率似乎在给药 1 周后达到平台期，并且在 RBC Pig-a 试验中甚至在第 4 周后它可能继续增加。这些结果表明，PIGRET 检测可以比原来的 RBC Pig-a 检测更早地检测到 Pig-a 突变体，并且可以在单次给药后 1 周内判断 EMS 的致突变性。