Caffeine and Ovariectomy Debilitate Bone Health in Rats on Calcium-deficient Diet

This study investigated the effects of ovariectomy and caffeine intake on bone health in rats on calcium-deficient diet. Forty adults female Wistar rats were divided into 4 groups in a 2x2 factorial design: Ovary (OVX/SHAM) and Caffeine (placebo/ caffeine). The animals were housed in individual cages for 8 weeks, receiving 18-20g of AIN-93M diet per day, containing 50% of the daily recommended intake of calcium. The rats underwent ovariectomy (OVX) or laparotomy (SHAM) surgery. Caffeine groups received 6mg of caffeine/kg/day. After euthanasia, the tibia and femur were dissected to determine the calcium content and bone fracture strength, respectively. Blood sample was collected to determine serum Ostase. 24-hour urine was analyzed for excreted calcium and NTx. Reduced bone fracture strength and calcium content were observed in OVX and Caffeine groups. When observed separately, OVX group showed increased urinary NTx and lower bone weight, blood ostase, and urinary calcium. Caffeine groups showed elevated urinary calcium. There was a positive correlation between bone fracture strength and calcium content. NTx correlated negatively with bone calcium, fracture strength and thickness. In conclusion, both OVX and caffeine intake debilitate bone health in rats on calcium-deficient diet.