Human follicular fluid maturity and endothelial cell chemotaxis

Follicular fluid of varying maturity was collected from the largest Graafian follicle of 23 ovulatory patients during laparoscopy (five blood-stained samples were discarded) and from five patients undergoing oocyte collection for assisted reproduction. The endothelial cell (EC) chemotactic potentials of the samples were tested with bovine aortic ECs in modified Boyden Chambers and an EC density score was determined for each sample. Intra-assay coefficients of variation (CV) varied from 2.9-17%; inter-assay CV was 45%. Therefore, cell density scores were expressed in terms of positive and negative control values from their respective plates. Serum progesterone was positively correlated with EC chemotactic potential (R2 = 14.9%). There was no correlation with day of cycle, follicular diameter, serum luteinizing hormone (LH) or oestradiol, or follicular fluid total protein levels (all R2 < or = 6%). Five subjects were in early and four in mid-follicular phase, seven were in early and two in late LH surge, and there were also five in-vitro fertilization (IVF) specimens. There was a statistically significant difference between the EC chemotactic potential of the five groups by analysis of variance (F = 5.98; P = 0.006). There was no significant difference between the late LH surge and the IVF samples (two-sample t-test). The mean cell density was higher for these two groups than the other three (P < 0.01 in all cases; two-sample t-test). It is concluded that the EC chemotactic potential of human follicular fluid increases after the LH surge and before ovulation.