Lactobacillus plantarum Alleviates Metabolic Parameters, Serum Testosterone Levels, and Spatial Memory in High-Fat Diet-Induced Obese Aged Mice

Objectives: This study aimed to investigate the potential therapeutic effects of Lactobacillus plantarum (LP) treatment on metabolic parameters, testosterone levels, and spatial memory in aged male mice with high-fat diet-induced obesity. Methods: Male C57BL/6 mice aged thirty-four weeks were fed either a normal or high-fat diet for 36 weeks. In the last 8 weeks, mice were divided into the control vehicle-treated group (CON), obese vehicle-treated group (HFD), obese low-dose LP-treated group (HPL), and obese high-dose LP-treated group (HPH). Metabolic parameters, serum testosterone, sperm quality, and spatial memory were measured. Changes in brain and cecum morphology were observed. Statistical analyses were examined using Student's t-test to compare effects of high-fat diet feeding (CON vs. HFD) and one-way ANOVA for comparison of effects of LP treatment (HFD vs. HPL vs. HPH). Results: HPL and HPH groups had lower serum cholesterol, AST, and ALT levels, higher serum testosterone levels, and improved learning impairment in the Morris water maze test. High-dose LP treatment significantly improved serum glucose and insulin levels. LP treatment also ameliorated the reduced number of neurons in the cerebrum. Pathological characteristics of the cecum, including crypt depth and villus length, were increased. Conclusions: LP may be a potential therapeutic supplementation in late-onset hypogonadism via increasing testosterone levels and semen quality and improving spatial memory, brain, and cecum morphology. Funding Sources: National Science and Technology Council, R.O.C (NSTC112-2314-B-016-030).