Phenotype and cell proliferation activity of duct-like structures in human sublingual glands: a histological and immunohistochemical study.

UNLABELLED: There are several age-related microscopic changes in the salivary glands, including the increase in the number of duct-like structures (DLS). However, the true origin and the phenotype of the DLS are not known. OBJECTIVE: To evaluate the phenotype and the cell proliferation index of the DLS of human sublingual glands. MATERIAL AND METHODS: Sixty sublingual glands obtained from human cadavers were divided into two groups - 0-30 and 61-90 years old. The phenotype was estimated by immunostaining for cytokeratin 19 (CK 19) and the S-100 protein as well as by the presence of mucin and glycogen. The cell proliferation index was determined by the Ki-67 antibody. The histochemical techniques used periodic acid-Schiff (PAS) and Alcian Blue. In each captured microscopic field, the DLS were counted to establish a percentage for the staining profile. The statistical analysis was accomplished using Student's t-test, the Mann-Whitney test and Pearson's correlation coefficient (p<0.05). RESULTS: Comparing both groups, only CK 19 showed a statistically significant difference (p=0.033), with the strongest expression in the elderly group. There was no significant difference between PAS and Alcian Blue (p=0.270). In both groups, the immunostaining for CK 19 was stronger than that for S-100 (p=0.004;p<0.001), but there was no correlation between the two immunomarkers (ρ=-0.163; p=0.315). There was no immunostaining for Ki-67. CONCLUSIONS: DLS demonstrate a ductal phenotypic profile and do not present cell proliferation activity. DLS may represent a regressive process arising from acini or represent the result of metaplasia.

Phenotype and cell proliferation activity of duct-like structures in human sublingual glands: a histological and immunohistochemical study

There are several age-related microscopic changes in the salivary glands, including the increase in the number of duct-like structures (DLS). However, the true origin and the phenotype of the DLS are not known. Objective To evaluate the phenotype and the cell proliferation index of the DLS of human sublingual glands. Material and Methods Sixty sublingual glands obtained from human cadavers were divided into two groups - 0-30 and 61-90 years old. The phenotype was estimated by immunostaining for cytokeratin 19 (CK 19) and the S-100 protein as well as by the presence of mucin and glycogen. The cell proliferation index was determined by the Ki-67 antibody. The histochemical techniques used periodic acid-Schiff (PAS) and Alcian Blue. In each captured microscopic field, the DLS were counted to establish a percentage for the staining profile. The statistical analysis was accomplished using Student's t-test, the Mann-Whitney test and Pearson's correlation coefficient (p<0.05). Results Comparing both groups, only CK 19 showed a statistically significant difference (p=0.033), with the strongest expression in the elderly group. There was no significant difference between PAS and Alcian Blue (p=0.270). In both groups, the immunostaining for CK 19 was stronger than that for S-100 (p=0.004;p<0.001), but there was no correlation between the two immunomarkers (ρ=-0.163; p=0.315). There was no immunostaining for Ki-67. Conclusions DLS demonstrate a ductal phenotypic profile and do not present cell proliferation activity. DLS may represent a regressive process arising from acini or represent the result of metaplasia. .

Different role of isoproterenol and NOS inhibitors on salivary ducts of rats.

OBJECTIVES: Nitric oxide (NO) is a diffusible intracellular messenger that is present in saliva. Chronic treatment with isoproterenol, a beta receptor agonist, stimulates the release of NO from acinar cells and induces salivary gland hypertrophy. The aim of this study was to investigate the effect of NO synthesis inhibitors and isoproterenol on rat salivary glands. We analyzed salivary gland weight and the number of ducts per unit area (0.5mm(2)) by NADPH-diaphorase histochemistry (to identify the presence of the enzyme NO synthase-NOS) and haematoxylin-and-eosin (HE). METHODS: For 8 days male Wistar rats received daily single intraperitoneal injections of saline or a NOS inhibitor (40mg/kg N(omega)-nitro-L-arginine L-NOARG or N(omega)-nitro-l-arginine methyl ester L-NAME). This was followed, 30min later, by subcutaneous injection of isoproterenol (2 or 5mg/kg) or saline. RESULTS: Isoproterenol increased parotid and submandibular gland weights. Isoproterenol (2mg/kg) induced a decrease of ducts per unit area inversely correlated to the weight of the parotid gland. This effect was augmented by L-NAME. In the submandibular gland L-NAME attenuated isoproterenol (2mg/kg) weight increase. In the submandibular gland isoproterenol and NOS inhibitors induced an increase in ducts per unit area (HE and NADPH-diaphorase). No effect was observed in the sublingual gland. CONCLUSION: To our knowledge this is the first description of isoproterenol and NOS inhibitors increasing duct density in the submandibular gland. Our results corroborate the hypothesis that NO plays different roles in parotid and submandibular glands.

Morphometric characterization of sexual differences in the rat sublingual gland.

The presence of morphological differences in the sublingual gland of male and female adult rats was determined by morphometry. Absolute and relative glandular mass was 21% lower and 31% higher, respectively, in females than in males. The fractions of glandular volume occupied by the mixed acini, intercalated ducts and striated ducts did not differ significantly between genders; however, their absolute volume was respectively 29, 42 and 58% higher in males. Despite the differences in the volume of these morphological compartments, the number of cells did not differ significantly between genders, except for the excretory duct compartment, for which a larger number was observed in males. With respect to cell volume, 13, 33 and 47% higher volumes were observed in males for mucous acinar cells and striated and excretory duct cells, respectively, while a 38% higher volume of serous demilune cells was observed for females. The surface-to-volume ratio of acini and striated ducts was respectively 16 and 35% higher in females. Based on these results, we conclude that the sublingual gland of female rats possesses smaller acini, and shorter ducts whose caliber is narrower, smaller mucous acinar and larger serous cells than the ones found in the male gland, indicating the presence of sexual dimorphism as well as suggesting sexual differences in the quality of the secreted product.

Morphometric characterization of sexual differences in the rat sublingual gland

A ocorrência de diferenças morfológicas entre sexos na glândula sublingual de ratos adultos foi verificada pela morfometria. As massas glandular absoluta e relativa das fêmeas foi, respectivamente, 21% menor e 31% maior que as dos machos. As frações de volume glandular ocupadas pelos ácinos mistos, ductos intercalares e ductos estriados não mostraram diferenças significantes entre sexos, no entanto, os seus volumes absolutos foram, respectivamente, 29%, 42% e 58% maiores nos machos. Apesar dessas diferenças nos volumes compartimentais, os seus conteúdos em número de células não apresentaram diferenças significantes entre sexos, exceto o compartimento dos ductos excretores, que mostrou maior número nos machos. Quanto ao volume celular, as células acinosas mucosas, as dos ductos estriados e as dos ductos excretores mostraram volumes, respectivamente, 13%, 33% e 47% maiores nos machos, e o das células das semiluas serosas foi 38% maior nas fêmeas. A relação superfície-volume dos ácinos e dos ductos estriados foi, respectivamente, 16% e 35% maior nas fêmeas. Baseados nos resultados obtidos, concluímos que as glândulas sublinguais das fêmeas exibem ácinos menores e ductos mais curtos e menos calibrosos e células acinosas mucosas menores e serosas maiores do que nos machos, indicando a ocorrência de dimorfismo sexual, e sugerindo que possa haver também diferenças na qualidade do produto secretado.

Postnatal development of the rat sublingual glands. A morphometric and radioautographic study.

The postnatal development of rat sublingual glands was analyzed by morphometric and radioautographic studies. The absolute number of each cell type was evaluated by the Aherne II morphometric method for cell counting and labeling indices of these cell types were determined in radioautographs from animals injected with 3H-thymidine. The quantitative cell population kinetic studies were accompanied by morphologic analysis of the modifications in each gland structure. The data concerning evolution of number of each cell type were submitted to analysis by least squares fit-exponential curve. The exponential equations duplication times for the acinar, serous demilune, intercalated duct, striated duct and stroma cells from 2 to 30 days of age were 7.5, 9.0, 10.8 and 9.5 days, respectively. On the other hand, the mean labeling indices for the same cell types during the same period were 9.5%, 5.8%, 7.2%, 3.3% and 4.3%, respectively. Thus, the intercalated duct cells exhibited the second highest labeling index and the slowest growth rate, while the striated duct cells showed the lowest labeling index and the third highest duplication time. The fact that the striated duct cell labeling index does not explain the relatively short duplication time of these cells, suggests that cells from other neighboring morphologic compartments, probably from intercalated duct, migrate and differentiate into striated ducts cells.

Estudo morfométrico e bioquímico do crescimento das glândulas sublinguais do rato durante a vida pós-natal / Morphometrical and biochemical study of the rat sublingual glands growth during postnatal period

As glândulas sulinguais do rato albino crescem marcadamente nos primeiros 40 dias de vida pós-natal. Na presente pesquisa estudamos a participaçäo da atividade proliferativa e do aumento do volume celular neste crescimento. A atividade proliferativa foi medida pelo aumento do DNA total avaliado bioquimicamente e o aumento do volume celular foi determinado por métodos morfométricos. A análise dos resultados mostrou que: a) o DNA aumentou 717 por cento (P < 0,01) no período de 2 a 40 dias de vida pós-natal; b) o volume das células acinosas mucosas exibiu flutuaçöes estatisticamente näo significativas até o 15§ dia, sofrendo, a partir daí, um aumento de 101 por cento (P < 0,05) até o 40§ dia; c) o volume das células das semiluas serosas mostrou decréscimo de 27 por cento (P < 0,05) no período de 10 a 15 dias, seguido de aumento de 71 por cento (P < 0,05) no período de 15 a 30 dias. Esses resultados indicam que o aumento significativo de massa de glândulas sublinguais do rato durante o período inicial de vida pós-natal, ocorreu principalmente por atividade proliferativa, e também, com menor participaçäo, por aumento de volume celular, notadamente das células acinosas mucosas.

Estudo estereológico dos ácinos de glândulas sublinguais de ratos jovens e adultos / Stereological study of the acini of the sublingual gland of young and adult rats

Em glândulas sublinguais, provenientes de ratas com 60 e com 140 dias de idade, avaliamos as dimensöes dos ácinos e dos seus constituintes celulares. Nos animais jovens os ácinos exibiram um volume total de 36,89 ñ 1,278mmü e uma superfície total de 23,24 ñ 0,965 cm², e estavam constituídos por 263,96 ñ 16,499 X 10(5) células mucosas com volume celular médio de 942,25 ñ 69,568µmü e 155,91 ñ 5,510 X 10(5) células serosas com volume celular médio de 633,33 ñ 26,017µmü. Por outro lado, as dimensöes morfométricas obtidas nos animais de 140 dias foram : volume e superfície totais de 51,61 ñ 3,131mmü e 34,84 ñ 1,838cm² , número absoluto de células mucosas e serosas de, respectivamente, 318,98 ñ 27,960 X 10(5) e 220,29 ñ 9,554X 10(5) e volume celular médio de 1002,83 ñ 89,062µmü e 661,29 ñ37,342µmü para as células mucosas e serosas. Esses resultados mostraram que o volume total dos ácinos cresceu, no período estudado, exclusivamente por atividade proliferativa, tanto de células mucosas como de células serosas

Autoradiographic evaluation of the cell cycle parameters of the various cells categories of the parotid, submandibular and sublingual glands of the suckling rat.

The evolution of the percentage of radioactive mitosis after a single thymidine-H3 injection, was determined for the various cell categories of the parotid, submandibular and sublingual glands of rats at 5th and 15th day of postnatal age. Estimates of the lengths of the S and the G2 + M/2 phases of the cell cycle were thus obtained, and averaged 9.8 and 2.7 hours, respectively, with extreme values of 9.3-11.2 and 1.6-3.2 hours.