Amnion mesenchymal stem cell metabolites reduce inflammation in diabetic salivary gland defect rat models

Objectives: Hyposalivation or xerostomia are well-established intraoral complications of diabetes mellitus (DM). Amniotic Mesenchymal Stem Cell Metabolite Products (AMSC-MPs) are being widely studied for their immunomodulatory action. However, their potential in a salivary gland defect model has yet to be explored. This study aims to determine the potential of AMSC-MPs in modulating the inflammatory response in the salivary glands of rats with persistent hyperglycemia, mimicking the pathogenesis of salivary gland disorders in DM. Methods: Forty-eight male pre-conditioned diabetic rats were divided into treatment and control groups. The treatment group received AMSC-MPs intraglandular injections, while the control group received phosphate-buffered saline intraglandular injections. Both groups were injected for 3, 5, 7, and 10 consecutive days. Subsequently, the submandibular salivary glands were biopsied and processed for formalin-fixed paraffin-embedded tissue for immunohistochemical assessment. The inflammatory response was assessed by quantifying the expression of tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), interleukin 10 (IL-10), and transforming growth factor β (TGF-β). Results: This study found significant downregulation of inflammatory cytokines, TNF-α and IL-6, in the AMSC-MPs intraglandular injections compared to the control (p < 0.05). Moreover, IL-10 and TGF-β expression, which may act as anti-inflammatory cytokines in this pathology, was significantly upregulated compared to the control (p < 0.05). Conclusion: Our study demonstrated the anti-inflammatory potential of AMSC-MPs intraglandular injections in a diabetes-induced salivary gland defect rat model.