Avaliação de expressão imuno-histoquímica de EGF e EGFR durante envelhecimento de glândulas salivares humanas

Abstract

Xerostomia is a complaint of many elderly individuals and is considered a major clinical problem in the field of geriatrics. Histological analysis has demonstrated that with increasing age, the parenchyma of the salivary glands is gradually replaced by fat and connective tissue. The epidermal growth factor (EGF) and EGF receptor (EGFR) are synthesized and secreted by salivary glands (SG); however, the physiological role of these proteins in saliva and in the maintenance of SG has not been fully elucidated. The objective of this study was evaluate alterations in expression of EGF and EGFR in the submandibular (SM), sublingual (SL) and minor labial (ML) SG during the aging process. The cases were divided into two groups for comparison: adult group, individuals between 30 and 60 years old; and elderly group, individuals over 60 years old. Expression of EGF and EGFR were evaluated by immnunohistochemistry. Quantitative analysis were assessed by Image J software. Analyzing the samples of ML, SL and SMSG, we observed that EGFR expression were more evident in serous and duct components than in mucosal cells. The Mann Whitney test demonstrated no difference in EGFR expression between the adult and elderly group for all groups of salivary gland analyzed (p>0.05). EGF expression in MLSG was more prominent in mucosal cells. EGF expression in serous cells of MLSG presented a more granular pattern in the adult group and a more diffuse pattern in the elderly group (p<0.05). Corroborates with this data the quantitative analyzes, demonstrating that EGF had a greater expression in the adult group than in elderly one (p<0.05). The SLSG analysis showed that EGF were most expressive in serous cells. There was higher expression of EGF in the cytoplasm of striated ductal cells of the elderly group when compared to the adult group (p<0.05). Quantitative analyzes showed no differences in EGFR expression, in SLSG between the groups analyzed (p>0.05). 8 EGF expression in SMSG was higher in serous cells and in the ducts. Comparing EGF expression in the adult group with the elderly one, we observed that no significant differences were detected (p>0.05). Analyzing the quantitative data, we also observed that there was no difference in the EGF expression between the two groups (p>0.05). EGF and EGFR was most expressed in SM, followed by SL. MLSG expressed smaller quantities of these proteins.