Apoptosis of cultured granulosa-lutein cells is reduced by insulin-like growth factor I and may correlate with embryo fragmentation and pregnancy rate

Objective

To correlate apoptosis of cultured human granulosa-lutein cells (GL cells) with the outcome of IVF (embryo fragmentation and pregnancy rate) and to study the effect of insulin and insulin-like growth factor I (IGF-I) on apoptosis.

Design

In vitro assays.

Setting

University laboratory and private IVF center.

Patient(s)

Eighty-one women undergoing IVF.

Intervention(s)

Purified human GL cells from pooled follicles were cultured for 48 hours in serum-free media with or without insulin and IGF-I. Cumulus cells and mural GL cells were evaluated separately.

Main Outcome Measure(s)

Detection of apoptosis by using caspACE FITC-VAD-FMK, a fluorescent in situ marker for activated caspases; embryo fragmentation; and pregnancy.

Result(s)

Age younger than 38 years and successful pregnancy were associated with less apoptosis (33.0% ± 17.2% vs. 43.2% ± 18.0% and 30.2% ± 14.0% vs. 40.4% ± 19.5%, respectively). There was a linear correlation between embryo fragmentation and GL cell apoptosis. Insulin-like growth factor I decreased apoptosis in a dose-dependent fashion. A statistically significant effect (17% decrease) was reached at a dose of 10 nM. Insulin (10 nM) caused a small (8%) decrease in apoptosis, but this effect did not reach statistical significance. Cumulus cells consistently had <3% apoptosis.

Conclusion(s)

[1] Apoptosis of cultured GL cells may be associated with IVF outcome and ovarian reserve and [2] IGF-I decreases apoptosis of cultured GL cells.

Key Words:  Granulosa-lutein cells , apoptosis , insulin , IGF-I , in vitro fertilization