Synergistic effect of green tea polyphenols and vitamin D on chronic inflammation‐induced bone loss in female rats

Abstract

This study examines effects of green tea polyphenols (GTPs) in conjunction with vitamin D (vitD) on chronic‐inflammation‐induced bone loss in female rats. A 2 (no GTPs vs. GTPs) ×2 (no vitD vs. vitD) factorial design using 40 female rats assigned to 4 groups, lipopolysaccharide implantation (L), L+0.5% GTP (LG), L+vitD (LD), and LPS+0.5% GTP+vitD (LGD) for 12 wks. Supplementation of GTPs in the drinking water increased concentrations of epigallocatechin in urine of rats. GTPs supplementation resulted in a decrease in inflammation index (total white blood cell count, WBC), DNA oxidative damage biomarker (8‐hydroxydeoxyguanosine level, 8‐OHdG), and bone resorption biomarker (tartrate resistant acid phosphatase, TRAP), no change in bone formation biomarker (osteocalcin, OC), and an increase in bone mineral density (BMD). VitD treatment also led to a reduction of 8‐OHdG and TRAP, no change in OC, and an increase in BMD. A combination of GTPs and vitD treatments resulted in a synergistic effect on BMD. These results demonstrated that GTPs in conjunction with vitD treatment mitigates LPS‐induced bone loss in female rats. Such a synergistic role of GTPs and vitD may be, in part, attributed to decreased inflammation and oxidative stress. This study suggests a potentially significant prophylactic role of green tea and vitD in bone health of women with chronic inflammation‐induced bone loss.