Does laser phototherapy influence the proliferation of myoepithelial cells in the salivary gland of hypothyroid rats?

Impact of photobiomodulation therapy on the morphological aspects of submandibular gland submitted to excretory duct ligation and hypothyroidism: an animal study

“…They were represented by the presence of edema, chronic inflammation, acinar atrophy, and fibrosis, findings that are not surprising after duct obstruction. However, the PBMT using low-power laser was found to influence the histopathological features, especially after 72 h. To our knowledge, this is the first study to evaluate the influence of PBMT on the inflammatory process that occurs in the submandibular glands of hypothyroid rats after ligation of the excretory duct, although previous studies from our group have investigated the influence of PBMT on salivary flow [6] and myoepithelial differentiation [15] in this metabolic disorder. At 24 and 72 h, the EU group that has salivary gland obstruction but was not irradiated exhibited edema and chronic inflammatory infiltrate rich in macrophages and some neutrophils replacing the fibrous and sometimes intralobular septa.…”

“…Obstruction of the salivary glands in humans [16] and laboratory animals is known to trigger inflammatory signs such as pain and edema [11][12][13][14]32] and irradiation with light sources such as laser light has been used in an attempt to control, reduce, or even improve these inflammatory alterations [6,15,17,18,20]. The therapeutic actions of laser light on analgesia and biomodulation of inflammatory processes generally occur in the red and infrared spectrum (approximately 600 to 900 nm) [35].…”

“…Although there are studies addressing the structural and functional changes that occur after obstruction of the salivary gland excretory duct [11,13,14,32,33], to our knowledge, few investigations have evaluated the effect of PBM on the salivary gland of rats [6,15,17,18,29], especially in rats with metabolic disorders such as hypothyroidism [6,15]. We hypothesize that PBMT can modify the morphological features seen after excretory duct obstruction in the submandibular gland of rats with hypothyroidism.…”

“…In addition to the systemic alterations caused by hypothyroidism [1,3,4], other local changes such as obstructive sialoadenitis of the salivary glands can cause atrophy of the glandular parenchyma and, consequently, salivary hypofunction, especially when associated with an inflammatory process [6,[11][12][13][14][15]. The latter can cause edema and pain [16].…”

Does laser photobiomodulation prevent hyposalivation in patients undergoing head and neck radiotherapy? A systematic review and meta-analysis of controlled trials

“…Many studies have focused on PBM as a possible treatment for salivary gland dysfunction. Studies in animal models suggest that PBM may increase salivary flow (Simões et al, 2008), increase protein content in parotids (Simões et al, 2009a), modulate antioxidant systems (Ibuki et al, 2013;Simões et al, 2010b;Campos et al, 2014), regulate glycemic control in salivary glands (Ibuki et al, 2013;Simões et al, 2009b), reduce lipid accumulation in this tissue (de Castro et al, 2018) and increase myoepithelial cell proliferation (Uzêda-e-Silva et al, 2017). Human studies have shown that PBM is able to decrease xerostomia symptoms during chemotherapy (Arbabi-Kalati et al, 2013), increase unstimulated salivary flow in patients with medically induced hyposalivation (Terlević Dabić et al, 2016) and reestablish some degree of salivary flow in patients with idiopathic xerostomia (Lončar et al, 2011).…”