Evaluation of ovarian stiffness and its biological mechanism using shear wave elastography in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder with various contributing factors. Shear wave elastography (SWE) is a contemporary noninvasive imaging technique that reports on the elasticity of tissues. This study aimed to evaluate ovarian stiffness in patients with PCOS using transvaginal SWE, and investigate the potential biological mechanisms underlying increased ovarian stiffness. Patients with PCOS and healthy controls underwent transvaginal 2D ultrasound and SWE to measure the number of follicles, ovarian volume, and ovarian elasticity. Multivariate logistic regression analysis was conducted to identify risk factors for PCOS. A rat model of PCOS was established to further investigate the biological basis of increased ovarian stiffness. Histological analysis, enzyme-linked immunosorbent assay, quantitative reverse transcription-polymerase chain reaction, western blotting, transcriptomics, and proteomics were performed to assess alterations in fibrosis and basement membrane (BM) gene expression. The results demonstrated that patients with PCOS (n = 59) showed an increased number of follicles, ovarian volume, and SWE (mean and max) compared with controls (n = 56; P < 0.001). The number of follicles, ovarian volume, and SWE_mean were identified as independent risk factors for PCOS (P < 0.05). SWE_mean ≥ 12.5 kPa demonstrated an area under the curve of 0.816 for PCOS diagnosis and was positively correlated with AMH levels (r = 0.6776, P < 0.0001). In the rat model, increased ovarian stiffness was associated with significant fibrosis and altered expression of fibrosis-related markers. Transcriptomic and proteomic analyses revealed that BM gene alterations were correlated with ovarian stiffness, which was further validated using PCOS patient data from the Gene Expression Omnibus database. In conclusion, SWE is a valuable technique for diagnosing PCOS by detecting increased ovarian stiffness, which may be associated with alterations in the expression of BMs, thereby mediating ovarian fibrosis.