Chronic caffeine intake alters collagen deposition in long bones: an experimental preliminary study

This study explores the impact of chronic caffeine intake on collagen deposition in long bones and correlates it with morphometric and metabolic alterations in Wistar rats. Animals had either regular drinking water (Control group) or caffeinated drinking water in a 300 mg/L dose (Caffeine group) for 12 wk. Using Picro-Sirius red collagen staining, cortical (78.07 ± 1.27 vs 82.12 ± 1.22) and trabecular (74.29 ± 1.09 vs 77.97 ± 1.03) collagen percentages in the caffeine group were markedly (p = 0.0448 and p = 0.0351; respectively) lower than the control group. Caffeine intake induced apparent alterations in the microstructure of cortical diaphysis and femoral head trabecular density as determined by micro-CT. In caffeinated animals, levels of bone-related metabolic biomarkers including BALP (1.41 ± 0.06 vs 1.12 ± 0.07), CTX (313.5 ± 20.78 vs 224.3 ± 27.19), DPD (11.61 ± 0.72 vs 9.26 ± 0.62), BGP (10.35 ± 0.43 vs 9.14 ± 0.34), and TRAP (4.34 ± 0.08 vs 4.01 ± 0.11) were increased (p = 0.0136, p = 0.0262, p = 0.0343, p = 0.0571, and p = 0.0461; respectively) as compared to control animals. Except for BALP (p = 0.0175) and DPD (p = 0.0423), the Pearson correlation between collagen bone deposition and microstructures and metabolic changes was not statistically significant. Collectively, chronic caffeine consumption restricts cortical and trabecular collagen deposition in long bones leading to microstructure and metabolic alterations.