## 1 Introduction  
Fibroblasts play a major role in supporting many tissue structures and are important cells in the dermis that can secrete cytokines and thus participate in multiple healing stages [1; 2; 3]. Human skin fibroblasts (HSFs) are the main cell component in the dermis of human skin and form the main body of the dermis together with its own secreted elastic fibers, collagen fibers, and matrix components [4]. Numerous studies have demonstrated that HSF cells are important for the skin aging process [5; 6; 7]. UVA-induced oxidative stress damage and H\({}_{2}\)O\({}_{2}\)-induced oxidative stress damage are two common models of oxidative stress damage. When UVA/H\({}_{2}\)O\({}_{2}\) stimulates HSF cells, the cells undergo oxidative injury, and the composition of antioxidant-related enzymes in the cells changes. Therefore, scientific research often establishes oxidative damage models to evaluate the efficacy of active substances. Fibroblasts produce a large amount of active oxygen following excessive ultraviolet radiation based on the dose of ultraviolet light, while H\({}_{2}\)O\({}_{2}\) is the main component of active oxygen [8; 9]. At very high concentrations, reactive oxygen species inhibit cell proliferation and lead to cell apoptosis [10]. UVA and H\({}_{2}\)O\({}_{2}\) eventually cause oxidative stress damage to the skin [11; 12; 13; 14]. Protecting the tissues from unwanted side effects is one strategy to lessen the unfavorable consequences of UVA and H2O2 in medical practice. As a result, the therapeutic benefits of natural compounds with antioxidant capabilities that may lessen the severity of UVA and H2O2-induced toxicities could be advantageous. Antioxidants are widely utilized as nutrients, and their effectiveness in reducing tissue and organ toxicity from various medicines was studied. Numerous studies have looked at the effectiveness of antioxidants as nutrients in reducing tissue and organ toxicity caused by a variety of conditions. Reactive oxygen species damage can be avoided and repaired by endogenous and exogenous antioxidants (ROS). They are referred to as \"free radical scavengers\" because they can strengthen the immune system and reduce the danger of sickness and toxins. Superoxide and other peroxides are chelated by enzyme-based antioxidants, such as catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD). They serve as defense mechanisms against endogenous antioxidants, clearing ROS activity and buildup in cells and preserving redox balance [15; 16; 17; 18]. The PI3K/AKT signaling pathway is implicated in many key cell functions, such as protein synthesis, cell cycle, apoptosis, drug-resistant growth factors (EGF, NGF, and VEGF), hormones (prostaglandins and PGE2), and cytokine stimulation [19; 20; 21]. Collagen type I \(\alpha\) 1 chain (COL1A1) and Collagen type I \(\alpha\) 2 chain (COL1A2) encode the front \(\alpha\)1 and \(\alpha\)2 chains of type I collagen [22]. Collagen type IV \(\alpha\) 5 chain (COL4A5) encodes one of the six subunits of type IV collagen, which is the main structural component of the basement membrane. Fibronectin 1 (FN1) is a kind of high-molecular-weight glycoprotein involved in a variety of biological functions, and its overexpression inhibits cell apoptosis by activating the PI3K/AKT signaling pathway [23; 24]. Ectoin is an amino acid derivative that can balance the osmotic pressure of cells and can also protect enzymes, DNA proteins, and nucleic acids under extreme conditions, such as high levels of radiation [25]. Ectoin can reduce the effects of UVA-induced damage in human keratinocytes and fibroblasts by preventing the release of secondary messengers, the activation of AP-2, the expression of intercellular adhesion molecule-1, and the mutation of mitochondrial DNA [26]. Researchers suggest that Ectoin may also play an important role in increasing the activity of antioxidant enzymes and the level of nonenzymatic antioxidants.