Fig. 7: Attenuated or excessive compressive stress leads to reduced follicle growth.

A Plot of mean follicle diameters (square: initial D < 150 µm, circle: initial D > 150 µm) in the different conditions. Data is presented as mean±SD. B Plot of growth rates per day vs. follicle size in different conditions. C Boxplots of growth rates at pre-maturation and maturation phases in different conditions. For A–C, n = 96 (control), 89 (Blebb); n = 56 (0 kPa), 61 (10 kPa) follicles. D Volcano plots of DEG analysis of RNA-sequencing of GCs in Blebb vs control and 10 kPa vs. control showing fold change (FC) expression. DEGs are identified when FC > 2 and p < 0.05(Wald test). N = 4 replicates for each condition. E GSEA shows normalised enrichment scores (NES, Benjamini-Hochberg test) for multiple hallmark gene sets in Blebb vs. control (top) and in 10 kPa vs. control (bottom). Same pathways similarly affected in both sets are in red. F Boxplots of pHH3⁺ GCs in cultured follicles. n = 57 (control), 42 (Blebb), 17 (10 kPa) follicles. G Boxplots of CC3⁺ GCs in cultured follicles. n = 25 (control), 32 (Blebb); n = 28 (0 kPa), 24 (10 kPa) follicles. H Boxplots of follicle growth rates in the pre-maturation phase in different conditions. n = 72 (control), 86 (LPA); 38 (0 kPa), 46 (2.5 kPa) follicles. I Boxplots of pHH3⁺ GCs in cultured follicles at the pre-maturation phase. n = 37 (control), 40 (LPA) follicles; n = 32 (0 kPa), 32 (2.5 kPa) follicles. J Boxplots of CC3⁺ GCs in cultured follicles at the pre-maturation phase. n = 48 (control), 55 (LPA) follicles; n = 28 (0 kPa), 29 (2.5 kPa) follicles. K Percentage of extrusion events upon compressive stress perturbations. Symbols represent the rupture events in each experiment; bars represent the mean, and error bars represent the standard deviation. N = 5 (Control/Blebb; 0 kPa/10 kPa); 4 (Control/LPA; 0 kPa/2.5 kPa). L Left: schematic showing minimal increase of compressive stress by LPA or addition of 2.5 kPa dextran (moderately thick arrows) enhances GC mitosis and reduces GC apoptosis while maintaining the intrafollicular pressure and promoting follicle growth. Right: schematic showing significant alterations to compressive stress (stress release by Blebb in thin arrow or stress increase by 10 kPa dextran in thick arrow) enhance GC apoptosis while reducing GC mitosis, leading to reduced intrafollicular pressure build-up and decreased follicle growth. Significance was determined by a two-tailed Mann–Whitney U test (pairwise) in C, F–J. ns: p > 0.05. Boxplots show the mean (star), median (centre line), quartiles (box limits) and 1.5x interquartile range (whiskers). All data are from at least four biological replicates. Source data are provided as a Source Data file.