A pilot longitudinal spectral CT study of fructose-related bone microstructure in rats: exploring technical...

Assessing the unique advantages of spectral CT as a real-time, dynamic, and in vivo monitoring technique for investigating fructose intake-related bone microstructural changes in rats.

Eighteen 3-week-old male Sprague-Dawley rats were randomized into experimental (standard chow + 25% fructose water, n=9) and control groups (standard chow + sterile water, n=9) for 8 weeks. Spectral CT scans were performed at weeks 0, 4, and 8. Calcium (Water) [Ca(Water)], Phosphorus (Water) [P(Water)], and Hydroxyapatite (Water) [HAP(Water)] values of the left femur were measured, and their rates of change were calculated. After 8 weeks, left femurs were harvested for distal femur histology. HE staining assessed trabecular parameters: bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), and trabecular number (Tb.N). Inter-group comparisons of trabecular parameters, intra- and inter-group comparisons of spectral parameters and their change rates, and correlation analyses between trabecular and spectral parameters were conducted.

At week 8, the experimental group showed significantly higher BV/TV, Tb.Th, and Tb.N, but no difference in Tb.Sp versus controls. Spectral CT parameters were significantly elevated in the experimental group only at week 8. In both groups, parameters at weeks 4 and 8 exceeded baseline, and week 8 values exceeded week 4 values. The rates of change from 4 to 8 weeks (rate of change_4-8) were significantly lower than the rates of change from 0 to 4 weeks (rate of change_0-4) in both groups. No inter-group differences were found for rate of change_0-4, but the experimental group had significantly higher rate of change_4-8 and the rates of change from 0 to 8 weeks (rate of change_0-8). At week 8, BV/TV, Tb.Th, and Tb.N were positively correlated with all three spectral CT parameters, with BV/TV showing strong correlations (r = 0.893-0.901, P < 0.001).

Spectral CT, as a real-time, dynamic, and in vivo imaging tool, overcomes the limitations of traditional ex vivo studies by providing a novel, non-invasive quantitative research strategy for longitudinally tracking the effects of fructose intake on bone microstructure in rats. Furthermore, it successfully monitored the dynamic process of fructose-promoted bone mineralization over a short-term period.