Screening of Salivary Biomarkers of Bisphosphonate-Related Osteonecrosis of the Jaw in a Diabetic Rat Model

Diabetes is a significant risk factor for bisphosphonate-related osteonecrosis of the jaw (BRONJ), a severe oral complication with limited treatment options. Salivary testing offers a noninvasive approach for monitoring BRONJ risk; however, few studies have investigated salivary biomarkers in BRONJ. This study screened salivary biomarkers that reflect the progression of BRONJ under diabetic conditions. A diabetic BRONJ rat model was established to screen for diabetes-related biochemical biomarkers in saliva. Streptozotocin (STZ) administration elevated blood glucose and glycated albumin levels and altered lipid and renal function markers, confirming diabetes induction. Subsequent zoledronic acid (ZA) administration and extraction of the maxillary first molar delayed epithelialization, inflammatory cell infiltration, bone exposure, and necrosis in extraction sockets, indicating successful establishment of a diabetic BRONJ model. This model showed reductions in submandibular and sublingual gland size, as well as in acinar cell number. Although salivary secretion volume was reduced, saliva samples were successfully collected from all groups. Screening identified elevated urea nitrogen (UN) and total ketone bodies (T-KB) in the STZ + ZA group. These findings suggest that salivary UN and T-KB may reflect disease progression and serve as potential biomarkers for predicting BRONJ risk under diabetic conditions.