ENPP1 is correlated with insulin resistance and lipid metabolism disorders in the rat model of polycystic ovary syndrome

Abstract Purpose Previous studies have shown that ectonucleotide pyrophosphatase phosphodiesterase 1 (ENPP1) may be an inhibitor of the insulin signalling pathway, and insulin resistance (IR) is believed to be the core mechanism in the pathophysiology of polycystic ovary syndrome (PCOS). This study was aimed to investigate the expression of ENPP1 in different tissues of PCOS rats and to analyse its potential role in the pathophysiology of PCOS. Methods Eighteen 23-day-old Sprague-Dawley rats were divided into PCOS and control groups (n= 9/group). Samples were collected after 20 days. Pathological examination and immunofluorescence were performed. Western blotting results of ENPP1 in the ovaries were analysed. Serum levels of ENPP1, hormones, fasting blood glucose (FBG), serum lipids were measured. Results Levels of ENPP1, testosterone (T), FBG, fasting insulin (FINS), homeostasis model assessment of IR (HOMA-IR), free fatty acids (FFAs), leptin, cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) were significantly higher in PCOS group, while adiponectin (ADP) and high-density lipoprotein cholesterol (HDL-C) were significantly lower. Spearman’s rank correlation analysis showed that ENPP1 was correlated with T, HOMA-IR, FFAs, leptin, serum lipids and ADP. MRNA levels of ENPP1, BAX, and IRS1 were higher in the ovaries, skeletal muscle, subcutaneous fat, and visceral fat of PCOS rats, and the protein expression of ENPP1 was significantly higher in the ovaries. Conclusions Our results revealed that ENPP1 is highly associated with IR and lipid metabolism-related molecules, which may have play important roles in PCOS pathophysiological changes.