Human periodontal ligament stem cells (PDLSCs) are a unique population of cells located within periodontal tissue, playing a crucial role in maintaining tissue remodelling, homeostasis, healing, and regeneration. These stem cells exhibit self-renewal and differentiation capabilities, as evidenced by the positive expression of various pluripotency markers, multipotency markers, and neural crest-derived cell markers (Alvarez et al., 2015, Dominici et al., 2006, Peng et al., 2021). Moreover, hPDLSCs possess notable immunomodulatory properties, enabling them to influence inflammatory responses effectively (Wada et al., 2009). As a result, hPDLSCs are regarded as promising candidates for advancing regenerative tissue therapies (Mohebichamkhorami et al., 2022, Queiroz et al., 2021).

Additionally, hPDLSCs are considered a priority in response to mechanical force stimulation during tooth movement, mastication, and orthodontic treatment (Chansaenroj et al., 2024, Pakpahan et al., 2024, Rojasawasthien et al., 2025). Among the various mechanical forces, shear stress serves as a significant stimulus in the modulation of tissue remodelling across different types of tissues. This mechanical shear stress is generated by fluid movement outside the cells, such as in the circulatory system and interstitial fluid flow within tissues. The constant movement of fluid exerts pressure, leading to the generation of shear stress.

Several reports strongly support that shear loading significantly enhances osteoblast differentiation in various cell types, including mouse pre-osteoblast cells (MC3T3-E1), periodontal ligament stem cells (PDLSCs), mesenchymal stem cells (MSCs), and human osteoblast cells (Kapur et al., 2003, Kim et al., 2014, Pei et al., 2022, Zheng et al., 2016). Despite enhancing differentiation capability, shear loading influences cell viability and death in endothelial and vascular smooth muscle cells (Hermann et al., 1997, Ji et al., 2019, Kadohama et al., 2007, Li et al., 2005, Tian et al., 2013). Additionally, in vitro studies of MSCs and hPDLSCs demonstrated that shear stress significantly stimulates antioxidant and anti-inflammatory cytokines and chemokines capable of immune cell recruitment, which enhances cell proliferation, apoptosis, and the ability to modulate immune cell activity. Shear stress exhibits an anti-oxidative effect via increased expression of Cu/Zn superoxide dismutase SOD (Inoue et al., 1996, Tao et al., 2007). Furthermore, shear stress induced by orthodontic movement or in vitro stimulation significantly enhances the expression of inflammatory cytokine genes, thereby contributing to immunomodulation (Diaz et al., 2017, Maeda et al., 2007, Russell-Puleri et al., 2017, Suwittayarak et al., 2022).

Growing evidence indicates that shear stress plays a key role in regulating cellular responses across various cell types. These responses include cell migration, proliferation, differentiation, immunomodulation and cell viability. The present study aims to investigate the role of shear stress stimulation on the cellular viability of hPDLSCs and to elucidate associated mechanotransduction signalling. This study investigated whether shear stress promotes cell survival in serum-deprived environments.