Table 2.

Summary of studies using antibiotic-treated models to study the effects of microbiota on bone

Source	Strain	Gender	Treatment age	Treatment duration	Groups	Antibiotic used	Bone measurement	Findings
Cho et al.	C57BL/6J	Male, Female	4-week-old	3 weeks, 7 weeks	Control vs. antibiotics	low-dose penicillin, chlortetracycline, vancomycin	DEXA	Increased BMD at 3 week but not at 7 weeks
Cox et al.	C57BL/6J	Male, Female	Born, 4-week-old	Until 20-week-old	Control vs. antibiotic administered before born or weaning	low-dose penicillin	DEXA	Decrease bone mineral content in male; increase mineral content in female
Nobel et al.	C57BL/6J	Female	10-day-old	3 intermittent treatment in 30-day period	Control vs. antibiotic	Therapeutic dose of Amoxicillin and tylosin alone or combination	DEXA	developed larger bones than controls, increases in bone area and mineral content were most pronounced in the amoxicillin group
Yan et al.	BALB/c	Female	2-month-old	1 month	SPF vs. antibiotic mixture; SPF vs. vancomycin	Cocktail of ampicillin, vancomycin, metronidazole, and neomycin; Cocktail of gentamicin, ciprofloxacin, streptomycin, and bacitracin; Vancomycin alone	microCT, bone turnover markers	Increased bone mass, reduced bone formation marker in antibiotic treated mice
Guss et al.	C57BL/6J, WT and TLR5 KO		Born, 4-week-old	Until 16-week-old	WT vs. TLR5 KO; SPF vs. antibiotics	Ampicillin and neomycin	microCT, mechanic test	Wider and shorter femur, and less whole bone strength in TLR5 KO; Less bending strength in both WT and KO mice treated with antibiotics

Abbreviations: BMD: Bone mineral density; DEXA: dual energy X-ray absorptiometry; KO: knockout; WT: wildtype