In vitro fertilization using sperm activated by ML-2–3 isolated from Morinda lucida Bentham leaves

Abstract

Purpose: ML-2–3 is a novel tetracyclic iridoid derived from Morinda lucida Bentham leaves. This compound has anti-trypanosomal and anti-leishmanial effects. In this study, the authors investigated effects of ML-2–3 on in vitro fertilization (IVF) rates, motility, and acrosome reaction of the mouse sperm. Methods: IVF was performed using sperm from BALB/cByJJcl mice treated with ML-2–3. Computer-assisted sperm analysis (CASA) was performed on the sperm of C57BL/6J mice to investigate sperm motility. The effect of ML-2–3 on the acrosome reaction was examined by observing the fluorescence of sperm labeled with the acrosin-EGFP transgene. Results: ML-2–3 improved IVF in BALB/cByJJcl mice with low fertilization rates. The optimum concentration of ML-2–3 in sperm pre-culture medium was 20 µM, and no significant toxicity of ML-2–3 was observed in developing embryos at this concentration. ML-2–3 affected sperm motility but not the acrosome reaction. ML-2–3 increased the IVF rate of mouse sperm that had been refrigerated for 3 days. Conclusions: ML-2–3 can improve the outcome of IVF and motility without inducing the acrosome reaction in mice. These effects of ML-2–3 on sperm behaviors are different from those of the similar drugs.