Ozcan Erel, Leyla Didem Kozaci, Betul Ozbek Iptec, Ahmet Rifat Balik, Gulsen Yilmaz, Cemile Bicer

Effects of storage conditions on thiol disulfide homeostasis

We planned this study to research the effect of freeze-thaw number and storage temperatures on the tests of thiol-disulfide homeostasis. Dynamic thiol-disulfide homeostasis has a crucial role in antioxidant defense reactions. Thiol disulfide homeostasis is detected in serum samples. To gauge the steadiness at different storage temperatures, sera stored at -20°C and -80°C for 1, 2, 3, 6, and 12 months. To work out the effect of the freeze-thaw cycle, sera were frozen at -80°C and subjected to ten freeze-thaw cycles at 24-hour intervals. According to our results, native thiol, total thiol, and disulfide levels in human serum samples were stable at -20°C for three months and at -80°C for 12 months. After the third month at -20°C, native thiol and total thiol levels decreased while disulfide levels increased. Additionally, as the number of freeze-thaw cycles increased, native thiol and total thiol levels decreased, and disulfide levels increased. Our results show that storage at -20°C and an increasing number of freezethaw processes affect thiols levels. To get the most accurate results, repeated freeze-thaw cycles should be avoided the maximum amount possible. Also, samples should be frozen at -80°C if long storage times are required.

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