Effects of Benzodiazepines on Acinar and Myoepithelial Cells

Background: Benzodiazepines (BZDs), the most commonly prescribed psychotropic drugs with anxiolytic action, may cause hyposalivation. It has been previously shown that BZDs can cause hypertrophy and decrease the acini cell number. In this study, we investigated the effects of BZDs and pilocarpine on rat parotid glands, specifically on acinar, ductal, and myoepithelial cells.

Methods: Ninety male Wistar rats were divided into nine groups. Control groups received a saline solution for 30 days (C30) and 60 days (C60), and pilocarpine (PILO) for 60 days. Experimental groups received lorazepam (L30) and midazolam (M30) for 30 days. Another group (LS60 or MS60) received lorazepam or midazolam for 30 days, respectively, and saline for additional 30 days. Finally, other groups (LP60 or MP60) received either lorazepam or midazolam for 30 days, respectively, and pilocarpine for additional 30 days. The expression of calponin in myoepithelial cells and the proliferating cell nuclear antigen (PCNA) in acinar and ductal cells were evaluated.

Results: Animals treated with lorazepam showed an increase in the number of positive staining cells for calponin as compared to control animals (p < 0.05). Midazolam administered with pilocarpine (MP60) induced an increase in the proliferation of acinar and ductal cells and a decrease in the positive staining cells for calponin as compared to midazolam administered with saline (MS60).

Conclusion: We found that myoepithelial cells might be more sensitive to the effects of BZD than acinar and ductal cells in rat parotid glands.

Histomorphometric analysis of salivary gland in wistar rats treated chronically with two benzodiazepines

Benzodiazepines (BZDs), the most commonly prescribed psychotropic drugs with anxiolytic action, may cause hyposalivation. Therefore, this study sought to quantify the acini (N) in parotid glands of Wistar rats treated chronically with two BZDs (Lorazepam and Midazolan) and to verify the action of the pilocarpine when administered with these drugs. Ninety male Wistar rats were distributed in 9 groups according to the administration of: a) S30 - saline solution for 30 days; b) S60 - saline solution for 60 days; c) P60 - pilocarpine for 60 days; d) L30 - Lorazepam for 30 days; e) M30 - Midozolam for 30 days; f) LS60 - Lorazepam for 60 days and, after this period, 30 more days of saline solution; g) MS60 - Midazolam for 30 days and, after this period, 30 more days of saline solution; h) LP60 - Lorazepam and Pilocarpine for 60 days; i) MP60 - Midazolam and Pilocarpine for 60 days. A surgery was performed on the animals to remove the glands. After this, histological cuts were stained by hematoxylin and eosin, from which the N was quantified. The ANOVA and Games-Howell tests were used for statistical analysis. The L30 and M30 groups presented less N than did the S30 group (p<0.05). The LS60, MS60, and LP60 groups presented less N than did the S60 and P60 groups (p<0.05). No differences could be observed between the MP60 and S60 groups. The chronic administration of Midazolam and Lorazepam reduced acini, which may well have collaborated in the reduction of salivary flow previously verified. The association of Midazolam with Pilocarpine led to the reestablishment of acinar cells, which may have favored the restoration of the salivary flow formerly shown.