Impaired sperm maturation in conditional Lcn6 knockout mice.

Area of Science:

• Reproductive biology
• Molecular and cellular biology
• Biochemistry

Background:

• Lipocalin 6 (LCN6) is a protein found on sperm surfaces, predominantly expressed in the epididymis.
• The in vivo biological function of LCN6 has remained largely unknown.

Purpose of the Study:

• To investigate the in vivo function of LCN6 in sperm maturation and function.
• To determine the role of LCN6 in regulating the acrosome reaction and calcium levels in sperm.

Main Methods:

• Generated a conditional knockout mouse model to disrupt the Lcn6 gene in adult mice.
• Assessed spermatogenesis, natural birth rates, in vitro fertilization (IVF) ability, acrosome reaction frequency, and intracellular calcium content in sperm from knockout and wild-type mice.

Main Results:

• Spermatogenesis and natural birth rates were unaffected by Lcn6 deficiency.
• Sperm from Lcn6 null mice exhibited a significant increase in acrosome reaction frequency, regardless of capacitation status.
• Knockout mice sperm showed significantly elevated intracellular calcium levels upon extracellular calcium supply, indicating premature acrosome reaction.

Conclusions:

• LCN6 plays a crucial role in preventing premature acrosome reaction and calcium overload in sperm.
• LCN6 deficiency may represent a risk factor for impaired sperm maturation and potentially reduced fertility.