Cholesterol-loaded cyclodextrin improves motility and survival of cryopreserved zebrafish (Danio rerio) sperm.

We studied the impact of modulating cholesterol levels in zebrafish sperm plasma membranes using cholesterol-loaded methyl-β-cyclodextrin (CLC) and unloaded methyl-β-cyclodextrin (MβC). Zebrafish sperm were treated with these substances before cryopreservation, and post-thaw sperm motility and in vitro fertilization (IVF) rates were compared between treated and untreated samples. Our findings indicate that adding cholesterol to sperm membranes increases post-thaw motility, motile cell count, and motile cell survival within a 0.5-4.0 mg per 1.2 × 10 ⁸  cell concentration range. Conversely, depleting cholesterol using MβC at 1.0 and 2.0 mg per 1.2 × 10 ⁸  cells reduced these parameters. On average, all CLC-treated sperm samples produced a 15 % higher IVF rate compared to untreated sperm. Including CLC in the extender before cryopreservation is beneficial for post-thaw sperm quantity and quality in zebrafish.
Competing Interests: Declaration of competing interest No competing personal or financial interests exist. We have not used any generative AI or AI assisted technologies during the preparation of this manuscript, except for the MS-Word Editor grammar and spell check.
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