Gestational diabetes mellitus (GDM) is a serious complication of pregnancy that is characterized by high blood sugar levels that occur due to insulin resistance and dysfunction in glucose metabolism during pregnancy. It usually develops in the second or third trimester of pregnancy and affects about 7 % of all pregnancies worldwide. In this experimental study, we scrutinized the GDM protective effect of soy isolate protein against streptozotocin (STZ) induced GDM in rats and explore the underlying mechanism.

Sprague-Dawley (SD) rats were used in this experimental study. A 55 mg/kg intraperitoneal injection of streptozotocin (STZ) was administered to induce diabetes in female rats, followed by oral administration of soy isolate protein for 18 days. Body weight, glucose levels, and insulin were measured at different time intervals (0, 9, and 18 days). Lipid profiles, antioxidant levels, inflammatory cytokines, apoptosis parameters, and mRNA expression were also assessed. Pancreatic and liver tissues were collected for histopathological examination during the experimental study.

Soy isolate protein significantly (P < 0.001) reduced the glucose level and enhanced the insulin level and body weight. Soy isolate protein remarkably decreased the placental weight and increased the fetal weight. Soy isolate protein significantly (P < 0.001) decreased the HbA1c, hepatic glycogen, serum C-peptide and increased the level of free fatty acid. Soy isolate protein significantly (P < 0.001) altered the level of lipid, antioxidant and inflammatory cytokines. Soy isolate protein significantly (P < 0.001) improved the level of adiponectin, visfatin and suppressed the level of leptin and ICAM-1. Soy isolate protein significantly (P < 0.001) altered the mRNA expression and also restored the alteration of histopathology.

Based on the result, soy isolate protein exhibited the GDM protective effect against the STZ induced GDM in rats via alteration of TLR4/MyD88/NF-κB signaling pathway.