Effects of metformin on human gingival fibroblasts: an in vitro study

BMC Oral Health Alshibani et al. BMC Oral Health (2023) 23:292 https://doi.org/10.1186/s12903-023-02978-0 Open Access RESEARCH Effects of metformin on human gingival fibroblasts: an in vitro study Nouf Alshibani1*, Reem AlKattan1, Eman Allam2, Fahad A. Alshehri1, Manal Matouq Shalabi3, Nada Almuhanna4, Houriah Almarshad5 and Anfal Aljamili6 Abstract Objective To investigate the effects of metformin (MF) treatment on the matrix metalloproteinases (MMPs) and proinflammatory cytokines production from lipopolysaccharide (LPS) - stimulated human gingival fibroblasts (HGFs). Methods HGFs were obtained from subcultures of biopsies from clinically healthy gingival tissues of patients undergoing oral surgeries. Cell cytotoxicity assay was used to determine the effect of different concentrations of MF on viability of HGFs. HGFs were then incubated and treated with different concentrations of MF and Porphyromonas gingivais (Pg) LPS. MMP-1, MMP-2, MMP-8, MMP-9, IL-1β, and IL-8 expression analysis was performed using xMAP technology (Luminex 200, Luminex, Austin, TX, USA). Student’s t-test for a single sample was used to compare the mean values of the study groups with the control value. A p-value of <0.05 and 95% confidence intervals were used to report the statistical significance and precision of mean values. Results Concentrations of 0.5, 1- and 2-mM MF had a minimal non-significant cytotoxic effect on the HGFs and caused statistically significant reduction of MMP-1, MMP-2, MMP-8 and IL-8 expressed by the LPS-stimulated HGFs. Conclusion The results of the present study confirm that MF suppresses MMP-1, MMP-2, MMP-8 and IL-8 in LPSstimulated HGFs suggesting an anti-inflammatory effect of MF and potential adjunct therapeutic role in the treatment of periodontal diseases. Keywords Matrix metalloproteinases, Metformin, Human gingival fibroblasts, Periodontal diseases *Correspondence: Nouf Alshibani 1 Department of Periodontics and Community Dentistry, College of Dentistry, King Saud University, Riyadh, Saudi Arabia 2 Oral and Dental Research Division, National Research Centre, Cairo, Egypt 3 Department of Periodontics, College of Dentistry, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia 4 Saudi Board of Periodontics, Ministry of Health, Riyadh, Saudi Arabia 5 Saudi Board of Endodontics, Ministry of Health, Riyadh, Saudi Arabia 6 Prince Sultan Military Hospital, Madinah, Saudi Arabia Introduction Periodontal diseases have been considered the second most common oral disease affecting mankind since ancient times. Reports indicate that about 40–90% of the global population is affected by periodontitis, making it a significant worldwide public health problem. Periodontal diseases are the results of infections and inflammation of the gingival and bone tissues that surround and support the teeth. The inflammatory process is triggered by the plaque biofilm that accumulates on teeth surfaces. It is now well established that the pathogenesis of the disease is multifactorial and that the resultant tissue and bone loss occurs as a consequence of various interactions between the host immune response and the pathogenic © The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Alshibani et al. BMC Oral Health (2023) 23:292 bacteria [1–3]. The main infectious agents involved in the pathogenesis of periodontal diseases are mainly gramnegative anaerobic bacteria such as Porphyromonas gingivalis (Pg), Tannerella forsythia, and Aggregatibacter actinomycetemcomitans [4, 5]. Subsistence of these bacteria elicits the immune response characteristics of periodontal diseases associated with the release of several cytokines and enzymes that are largely responsible for the destruction of the gingival tissues and alveolar bone. One of the key host factors involved in these complex host immuno-inflammatory reactions is matrix metalloproteinases (MMPs) [6, 7]. MMPs are a family of structurally related but genetically distinct proteolytic enzymes that mediate the degradation of extracellular matrix (ECM) macromolecules, including interstitial and basement membrane components and are thus involved in various physiological and pathological conditions. Several MMPs have been recognized as main inflammatory and immune response regulators in periodontal diseases. Besides being involved in the regulation of the destructive periodontal inflammatory response, they are broadly responsible on the degradation of ECM and basement membrane components [7, 8]. The oral microbiome is extremely complex with the average adult harboring about 50–100 billion bacteria in the oral cavity representing about 200 predominant bacterial species. There is a strong correlation between the composition and diversity of oral microbiota and periodontal diseases. In addition, the interaction between the oral microbiota and the host immune response is a critical determining factor in the development and progression of periodontal diseases. The advancements in DNA sequencing and other molecular techniques have allowed researchers to better understand the compositional changes that occur in subgingival biofilms in the transition from health to gingivitis then to destructive periodontal disease. Full knowledge of the whole dynamic of the oral microbiota and its relationship with periodontal disease is crucial for improving diagnostics and setting new effective treatment strategies, such as targeted antimicrobial therapy and probiotics [9, 10]. Human gingival fibroblasts (HGF) are the predominant cell type in the periodontal connective tissue. These cells produce the components of the ECM, as well as the enzymes that degrade the ECM. The degradation of the collagen-containing tissues at the dento-epithelial junction initiates the formation of a periodontal pocket. This can eventually result in an inflammatory periodontal disease, which is characterized by a significant reduction in collagen fiber density in the gi (...truncated)