If you give tiny mice a special kind of jelly-like substance through their mouth for a week, it shows up in places like their eyes and bladder—even though they didn’t swallow it there—meaning it traveled through their body.

To test if oral 5 kDa hyaluronic acid distributes systemically, adult female C57BL/6J mice would be randomly assigned to receive either 5 kDa hyaluronic acid orally or a placebo, with blood and tissue samples (eyes, bladder, vagina, rectum) collected at multiple time points over 7 days and analyzed via mass spectrometry for hyaluronic acid concentration.

To visualize and confirm systemic distribution, 5 kDa hyaluronic acid would be labeled with a non-toxic fluorescent tag and administered orally to adult female C57BL/6J mice; tissues (eyes, bladder, vagina, rectum) would be excised at 24, 48, 72, 96, 120, 144, 168 hours and imaged using confocal microscopy to detect fluorescence above background.

To confirm systemic absorption, each mouse would receive both oral 5 kDa hyaluronic acid and oral saline in randomized order with a washout period; tissues would be harvested and analyzed for hyaluronic acid content using ELISA or HPLC to compare concentrations between treatment and control conditions.

To determine if the 5 kDa size is critical for systemic distribution, mice would receive oral doses of 5 kDa, 50 kDa, and 500 kDa hyaluronic acid; tissue levels in eyes, bladder, vagina, and rectum would be compared to assess molecular weight dependence.

To explore whether systemic detection is due to gut leakage, mice would be treated with oral 5 kDa hyaluronic acid while simultaneously measuring intestinal permeability (e.g., FITC-dextran assay) and gut histology to correlate tissue levels with barrier disruption.