The effects of simultaneous and separate supplementation of Lactobacillus Plantarum and inulin on serum and testicular levels of testosterone and anti-mullerian hormone, testicular Kisspeptin and androgen receptor protein expression and testicular changes in type 2 diabetic male rats

Abstract

Background: Type 2 diabetes mellitus (T2DM) is one of the most prevalent metabolic disease worldwide. It is established that impaired reproductive health is one of the notable long-term outcomes of T2DM, especially among males. Considering the global increasing rate of T2DM and infertility and their consequences on one side, and the useful effects of prebiotics, probiotics, and synbiotics in diabetes and infertility disorders on the other side, the present study was aimed to investigate the impact of Lactobacillus plantarum (L. plantarum), inulin, and their combinatory supplementation on testosterone and antimullerian hormone (AMH) as well as the expression of testicular kisspeptin and androgen receptor (AR) and testicular changes in T2DM male rats.

Materials and Methods: The present study was performed on 35 male Wistar rats for 8 weeks, divided into 6 groups. T2DM was induced by high-fat diet (HFD) for 4 weeks and then intraperitoneal injection of streptozotocin (STZ) (35 mg/ kgBW). L.plantarum was given daily to the rats at a concentration of 107 colony units per ml (CFU/ ml) for 8 weeks. Also, Inulin was administered based on 5% of the daily food intake of the rats and was dissolved in drinking water of each cage. At the end of the intervention, the blood sample was obtained from the heart of the rats for measurement of parameters, using ELISA method. Then, abdominal cavity was opened to extract the testis and epididym tissue for tissue passage. The tissue sample analysis was performed using Western blotting and biochemical tests assay. Results: Administration of L. plantarum and inulin in diabetic male rats improved sperm motility and viability (p<0.001, both) as well as testicular tissue development via increasing leydig cell number, testicular spermatid count, and diameter of seminiferous tubules (p<0.001, all). Testicular expression of Kisspeptin was elevated by inulin supplementation (p=0.01). However, L. plantarum administration increased testicular AR expression (p=0.01). The expression of Kisspeptin showed a remarkable correlation with fertility markers including tissue testosterone level, spermatid count, and sperm mobility (p<0.001, for all). No significant changes were observed in serum and testicular levels of AMH after the intervention. Conclusion: Eight-week daily supplementation of L.plantarum and inulin could have beneficial effects in the amelioration of reproductive complications in type 2 diabetic male rats. Furthermore, the results also suggested that testicular kisspeptin would have a role in spermatogenesis. Key words: Diabetes mellitus, Lactobacillus Plantarum, Inulin, testosterone, kisspeptin, androgen receptor, testis