Low-power laser irradiation decreases lipid droplet accumulation in the parotid glands of diabetic rats.

Lipid droplet accumulation has been related to salivary gland hypofunction in diabetes. In this study, the effect of laser irradiation on the parotid glands (PGs) of diabetic rats was analyzed with regard to its effect on lipid droplet accumulation, intracellular calcium concentration and calmodulin expression. The animals were distributed into 6 groups: D0, D5, D20 and C0, C5, C20, for diabetic (D) and control animals (C), respectively. Twenty-nine days following diabetes induction, PGs of groups D5 and C5; D20 and C20 were irradiated with 5 and 20 J/cm2 of a red diode laser at 100 mW, respectively. After 24 hours, PGs were removed for histological, biochemical, and western blotting analysis. The diabetic animals showed lipid droplet accumulation, which was decreased after irradiation. Ultrastructurally, the droplets were nonmembrane bound and appeared irregularly located in the cytoplasm. Moreover, diabetic animals showed an increased intracellular calcium concentration. In contrast, after laser irradiation a progressive decrease in the concentration of this ion was observed, which would be in agreement with the results found in the increased expression of calmodulin in D20. These data are promising for using laser to decrease lipid droplet accumulation in PGs, however, more studies are necessary to better understand its mechanisms. Micrographs showing decreased lipid accumulation after laser irradiation in light micrographs (LM), and morphology of lipid droplet in transmission electron microscopic (TEM). LM: (A) PGs from nondiabetic rats that did not receive Laser irradiation (LI), (B) PGs from nondiabetic rats that received a dose of 20 J/cm2 , (C) lipid accumulation (arrows) in the secretory cells from diabetic rats that did not receive irradiation, (D) reduction of lipid accumulation in the secretory cells from diabetic rats that received a dose of 20 J/cm2 and TEM: (E) scale bar = 5 µm, (F) scale bar = 1 µm, and (G) scale bar = 0.5 µm.

Ultrastructural and biochemical analysis of the effects of alendronate on salivary glands of young rats.

INTRODUCTION: The bisphosphonates are drugs known by their antiresorptive potency and are widely prescribed for treating and preventing osteoporosis. In the past years the employment of this class of drugs had spread to other pathologies, and it is being prescribed to patients in a wide range of ages. Some adverse effects of bisphosphonate treatment have been highlighted recently, however, little is known about its potential side effects in salivary glands. METHODS: Newborn rats received daily doses of 2.5mg/kg/day of sodium alendronate during 30 days. On the thirtieth day the animals were stimulated with pilocarpine and their parotid and submandibular glands were collected, fixed and embedded for histological and ultrastructural analysis. Some glands were collected for analysis of protein content and amylase activity. RESULTS: At light microscopy, the alendronate-treated animals presented an accumulation of secretion granules in their cytoplasm, which was confirmed by the ultrastructural examination. Biochemical analysis revealed an increase in total protein content and decreased amylase levels of both glands in the alendronate-treated animals in relation to the control. CONCLUSION: Based on the current findings, alendronate is probably interfering in secretory pathways of parotid and submandibular glands.