https://www.selleckchem.com/products/l-arginine-l-glutamate.html e damage in the paracellular pathway were involved in the hyposecretion of SMGs after irradiation. To study the effect and mechanism of low-level laser irradiation (LLLI) on lipopolysaccharide (LPS)-induced inflammatory injury of human periodontal ligament fibroblasts (hPDLFs). hPDLFs were inoculated into well plates and randomly divided into the normal group, LPS group, and LPS+LLLI group. The cells in the normal group were cultured in conventional medium. The hPDLFs in the LPS and LPS+LLLI groups were cultured in RPMI1640 medium containing 1 mg·L LPS. The three subgroups of the LPS+LLLI group were exposed to different LLLI. After 4 days, the cell apoptosis, viability, and intracellular free Ca concentration of each group were measured. The contents of tumor necrosis factor-α (TNF-α), interleukin (IL)-8, IL-1β, and IL-6 were measured by enzyme linked immunosorbent assay (ELISA). Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to detect the expression of matrix metalloproteinase (MMP)-2, MMP-3, and MMP-9 genes and proteins of hPDLFs in each group. Compared withe irradiation intensity is 4 J·cm-2.The maxillofacial skeleton is the basis of the contour of the face. Orthognathic surgery and facial contouring surgery change jaw tissue and affect facial appearance in different manners. Orthognathic surgery is the main method to correct dental and maxillofacial deformities. It changes the shape of the jaw and improves the occlusal relationship by changing the three-dimensional position of the jaw. Facial contouring surgery mainly adopts the method of "bone reduction", which changes the "amount"of the jawbone by cutting a part of the bone tissue to improve the facial appearance, generally without changing oral function. The combined use of orthognathic surgery and facial contouring surgery is becoming increasingly common in clinical practice. This also requires oral and maxi