Intake of probiotic bacteria may improve or preserve insulin sensitivity. Fetuin-A and sestrin 3 have emerged as promising candidate biomarkers for crucial roles in insulin signaling pathway. Therefore, the effect of oral supplementation with the probiotic bacterium Lactobacillus delbrueckii subsp. lactis PTCC1057 on proteins involved in insulin signaling pathway was investigated in normal and streptozotocin (STZ)-induced diabetic mice. The 6-8-week-old female mice were divided into a non-diabetic control, diabetic control, and diabetic experimental and non-diabetic experimental groups (5 mice each group). Diabetic and non-diabetic experimental groups treated with 3 × 107 CFU mL-1 L. delbrueckii subsp. lactis PTCC1057 by gavage feeding approach daily for 28 days. Serum glucose, fetuin-A, and sestrin 3 levels were measured by standard methods. The result showed that oral administration of L. delbrueckii significantly decreased serum glucose in comparison to diabetic control group (P = 0.01). Serum fetuin-A level was higher in diabetic control group than non-diabetic group and oral administration of L. delbrueckii subsp. lactis PTCC1057 significantly decreased fetuin-A level in diabetic experimental group in comparison with non-diabetic groups (P = 0.001). Sestrin 3 level significantly was lower in diabetic control group than non-diabetic control group (P = 0.03) and it significantly increased in diabetic experimental group in comparison with diabetic control group after intervention of L. delbrueckii subsp. lactis PTCC1057 (P = 0.02). The results show that feeding the STZ-induced diabetic mice with L. delbrueckii subsp. lactis PTCC1057 terminated to decrease in fasting blood glucose and fetuin-A level and increase in serum sestrin 3 level. Therefore, the L. delbrueckii subsp. lactis PTCC1057 can be considered as excellent candidate for future studies on diabetes mellitus.
Keywords: Fetuin-A; Lactobacillus delbrueckii subsp. lactis PTCC1057; STZ; Sestrin 3; Streptozotocin; Type 2 diabetes.