Immunohistochemical expression of estrogen receptor alpha in the maxillary sinus, pulp, and periodontal ligament of adjacent teeth in late pregnancy in rats.

This study aimed to assess the histological changes in the maxillary sinus and its adjacent dental tissues as pulp and periodontal ligament during pregnancy and investigate the role of estrogen hormone in these changes through the detection of estrogen receptors in these tissues. Sixteen adult female rats were used and were allocated into two groups: control non-pregnant (n = 8) and pregnant (n = 8). They were sacrificed and their heads were prepared for histological and immunohistochemical examination for estrogen receptor alpha. Our results revealed that pregnant rats revealed inflammatory changes in the sinus as thick epithelial lining, loss of cilia, swollen goblet cells, intraepithelial and interstitial edema. The lamina propria demonstrated considerable infiltration of inflammatory cells, glandular hyperplasia with vacuolar degeneration, and vascular congestion. Periodontal ligament and pulp revealed hyperemia and vascular congestion. Immunohistochemical examination of estrogen receptor alpha in the maxillary sinus and adjacent dental tissues (Periodontal ligament and pulp) in pregnant rats revealed a significant increase in its expression in all examined tissues. In conclusion, there was an increase in expression of ERα in the sinus mucosa and dental tissues during pregnancy together with slight inflammatory changes in these tissues. Hence, dentists should be aware of the effect of these changes on the pregnant women avoiding teeth extraction due to misdiagnosis of dental, periodontal or sinus pain after exclusion of true pathologies.

Thyroidectomy induces thyroglobulin formation by parotid salivary glands in rats.

Structural changes in parotid gland (PG) were previously reported following ablation of thyroid gland. However, the functional alterations (especially for proteins) have not been elucidated yet. Herein, we investigated the effect of rat thyroidectomy on PG structure and protein content and studied the ability of thyroxin-supplementation to alleviate the associated structural and functional changes. Male young adult 4-month old albino rats (n = 48) were allocated equally into 4 groups (control, sham-operated, thyroidectomized, and thyroxin-supplemented). PGs were examined histologically, and their proteins expression and localization were analyzed using western blot (WB) and immunohistochemistry (IHC), respectively at 3 w and 5 w post-surgery. Functionally, PGs of thyroidectomized rats formed a newly expressed 300 KDa protein, which was confirmed to be thyroglobulin (TG) by WB and IHC, with higher expression at 5 w. TG was localized in the interstitium, within capillaries, in the cytoplasm of the intralobular ductal cells, in the secretory products within the ductal lumen, and in the cytoplasm of individual small cells at the periphery of the acini. This functional change accompanied by structural changes in PGs (presence of dark and light acinar cells, TG-like colloid material, and high periductal vasculature). Noteworthy, PG of the thyroxin-supplemented depicted vanishment of TG. From these data, it could be concluded that thyroidectomy could alter the morphology and function of the parotid that induce a thyroid-like reprogramming of the parotid to secrete TG and thyroxin supplementation could alleviate this effect.