Supportive Role of Probiotic Strains in Protecting Rats from Ovariectomy-Induced Cortical Bone Loss Nima Montazeri-Najafabady 1,2 & Younes Ghasemi 1,3 & Mohammad Hossein Dabbaghmanesh 2 & Pedram Talezadeh 2 & Farhad Koohpeyma 2 & Ahmad Gholami 1,3 # Springer Science+Business Media, LLC, part of Springer Nature 2018 Abstract Osteoporosis is a major health problem that occurs as a result of an imbalance between bone formation and bone resorption. Different approaches have been established for treating osteoporosis. Recently, because of their health benefits and also low adverse reaction, probiotics have been receiving considerable attention. In this study, we compared the effectiveness of five probiotic strains, Lactobacillus acidophilus, Lactobacillus reuteri, Lactobacillus casei, Bifidobacterium longum, and Bacillus coagulans, in protecting rats from ovariectomized (OVX)-induced bone loss. Forty-nine adult female Sprague-Dawley rats were allocated into seven groups as follows: group 1, control; group 2, OVX; group 3, OVX + Lactobacillus acidophilus; group 4, OVX + Lactobacillus casei; group 5, OVX + Bacillus coagulans; group 6, OVX + Bifidobacterium longum; and group 7, OVX + Lactobacillus reuteri. Probiotics were fed to OVX groups at the concentration of (1 × 10 9 CFU/ml/day) for 4 weeks. Then, biochemical parameters, including vitamin D, calcium (Ca), phosphorus (P), and alkaline phosphatase (ALP), were assessed. Dual-energy X-ray absorptiometry (DEXA) scans were used that assess bone mineral density (BMD), bone marrow concentra- tion (BMC), and area of global, femur, spine, and tibia. Lactobacillus acidophilus and Lactobacillus casei significantly increased Ca and ALP and decreased P in treated groups. Lactobacillus casei, Lactobacillus reuteri, and Bifidobacterium longum increased vitamin D significantly. Lactobacillus acidophilus and Lactobacillus casei indicated the most effects on BMD. In terms of BMC, and bone area, Lactobacillus acidophilus, Lactobacillus reuteri, and Lactobacillus casei demonstrated the significant enhance- ment in OVX groups treated with. Among the probiotics used in this study, Lactobacillus acidophilus and Lactobacillus casei showed the most effects in terms of BMD, BMC, bone area, and biochemical parameters. It seems that probiotics effects on bone health are strain dependent, but further studies should be done to prove these findings. Keywords Osteoporosis . Probiotics . Bone loss . Lactobacillus . Bacillus coagulans . Bifidobacterium . Nutraceuticals Introduction Osteoporosis is known as a bone metabolic disorder which is defined by low bone mass and microarchitectural deterioration of bone tissue, leading to increasing the fracture risk [1]. Osteoporosis fracture as one of the major problems in old age affects morbidity and mortality of the patients and causes some economic and social issues. It is expected that in 2020, half of * Ahmad Gholami Gholami@sums.ac.ir Nima Montazeri-Najafabady montazerin@sums.ac.ir Younes Ghasemi ghasemiy@sums.ac.ir Mohammad Hossein Dabbaghmanesh Dabbaghm@sums.ac.ir Pedram Talezadeh Ptalezadeh@yahoo.com Farhad Koohpeyma fFarhad_biologist@yahoo.com 1 Pharmaceutical Science Research Center and Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran 2 Endocrinology and Metabolism Research Center, Shiraz University of Medical Sciences, Shiraz, Iran 3 Biotechnology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran Probiotics and Antimicrobial Proteins https://doi.org/10.1007/s12602-018-9443-6