Aim
To evaluate the influence of the addition of microparticulate (micro) and nanoparticulate (nano) zirconium oxide (ZrO2) and niobium pentoxide (Nb2O5) to a calcium silicate‐based cement (CS) on ...the subcutaneous healing process in rats compared with MTA Angelus™.
Methodology
In each rat, two polyethylene tubes filled with the following materials: (i) MTA; (ii) CS + ZrO2micro; (iii) CS + ZrO2nano; (iv) CS + Nb2O5micro or (v) CS + Nb2O5nano were implanted subcutaneously; empty polyethylene tubes were used in the Control group. After 7, 15, 30 and 60 days, the specimens (n = 5 per group in each period) were fixed and embedded in paraffin. Masson's trichrome sections were used to obtain the volume density of the inflammatory cells (VvIC) and fibroblasts (VvFb). The sections were also stained with Picrosirius‐red to calculate the birefringent collagen content. Fibroblast growth factor‐1 (FGF‐1) was detected by immunohistochemistry, and the number of immunolabelled cells was obtained. The data were subjected to two‐way anova followed by Tukey's test (P ≤ 0.05).
Results
At all periods, the VvIC was significantly lower (P < 0.001) in all the CS and Control groups than in the MTA group. At all periods, the VvFb was reduced significantly (P = 0.023) in the MTA group in comparison with the other groups. In addition, the number of immunolabelled cells in the capsules of the CS groups was significantly higher (P < 0.001) than in the MTA group at all time‐points.
Conclusions
The experimental materials (CS + ZrO2 and CS + Nb2O5) induced fibroblast proliferation and accelerated the regression of the inflammatory reaction. However, the addition of nanoparticulate radiopacifiers did not improve the biological properties of a calcium silicate‐based cement when compared to microparticulate agents.
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BFBNIB, CMK, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Aim
To evaluate the inflammatory process induced by Biodentine and mineral trioxide aggregate (MTA) in rat subcutaneous tissues.
Methodology
A polyethylene tube filled with Biodentine (n = 20) or MTA ...(n = 20) was placed into the dorsal subcutaneous of forty male rats; in the control group (CG; n = 20), empty tubes were implanted. After 7, 15, 30 and 60 days, the polyethylene tubes surrounded by connective tissue were fixed and embedded in paraffin. The number of inflammatory cells was estimated in HE‐stained sections; numerical density of interleukin‐6 (IL‐6)‐immunolabelled cells was also performed. The differences amongst the groups were analysed statistically by Tukey's test (P ≤ 0.05).
Results
A high number of inflammatory cells and IL‐6‐positive cells were observed at 7 days, in all groups; however, in the Biodentine group, the number of inflammatory cells and IL‐6‐immunolabelled cells was significantly higher (P ≤ 0.05) in comparison with the other groups at 7 and 15 days. In the capsules of animals from all groups, a gradual and significant reduction (P ≤ 0.05) of these parameters was seen over time. At 60 days, the capsules exhibited numerous fibroblasts and bundles of collagen fibres; in addition, the number of IL‐6‐positive cells was not significantly different amongst Biodentine, MTA and control groups.
Conclusions
There was a significant regression in the inflammatory reaction in the capsules indicating, therefore, that Biodentine is a biocompatible material.
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BFBNIB, CMK, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Aim
To compare the formation of fibrous capsules around Biodentine and MTA Angelus implants as well as the participation of fibroblast growth factor‐1 (FGF‐1) and mast cells in the tissue response to ...these endodontic materials.
Methodology
Sixty polyethylene tubes filled with Biodentine or MTA, and empty tubes (control group) were implanted into the dorsal subcutaneous tissues of male rats. After 7, 15, 30 and 60 days, the specimens were embedded in paraffin and the number of fibroblasts and mast cells was quantified in the sections stained with Masson's trichrome or Alcian Blue, respectively. FGF‐1 and Ki‐67 were detected by immunohistochemistry, and the number of immunolabelled cells was computed. The collagen content was estimated in the picrosirius red‐stained sections. The data were subjected to two‐way ANOVA followed by Tukey's test (P ≤ 0.05).
Results
The capsules were associated with a significant increase (P < 0.0001) in the number of fibroblasts and mast cells, and in the collagen content over time. A significant decrease (P < 0.0001) in the immunoexpression of FGF‐1 and Ki‐67 was observed in all groups from the 7th–60th day. At 60 days, the number of fibroblasts (P = 0.0226) and the collagen content (P < 0.0001) were significantly greater in MTA than Biodentine specimens, while the greatest number of mast cells and FGF‐1‐immunolabelled cells was observed in Biodentine specimens (P < 0.0001). A significant difference in Ki‐67 immunoexpression was not detected between specimens of Biodentine and MTA.
Conclusions
The collagen‐rich capsule formed slowly around Biodentine in comparison with MTA. FGF‐1 and mast cells participated in capsule remodelling, stimulating fibroblast proliferation and subsequent collagen production, in response to subcutaneous implants.
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BFBNIB, CMK, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Aim
To evaluate the periodontium response to tricalcium silicate (TCS) with zirconium oxide (ZrO2) or niobium oxide (Nb2O5) used in the sealing of perforated pulp chamber floors in rat maxillary ...molars.
Methodology
In eighty rats, the perforations in right maxillary molars were filled with either TCS + ZrO2, TCS + Nb2O5, White MTA (used as a gold standard material) or no repair material was placed (Sham Group, SG); the left molars of SG, were used as controls (CG). Sections of maxillary fragments following 7, 15, 30 and 60 days were used to evaluate the volume densities of inflammatory cells (VvIC) and fibroblasts (VvFb), width of the periodontal space, amount of collagen, number of osteoclasts and number of IL‐6‐immunostained cells. The data were subjected to two‐way ANOVA followed by Tukey’s test (P ≤ 0.05).
Results
At all periods, significant differences in VvIC were not detected among TCS + ZrO2, TCS + Nb2O5 and MTA groups, which had values significantly lower (P < 0.05) than the SG. Significant differences in the number of IL‐6‐immunolabelled cells were not observed among TCS + ZrO2, TCS + Nb2O5 and MTA groups (P > 0.05) at 15, 30 and 60 days. At 7, 15 and 30 days, the number of osteoclast was significantly greater in TCS + ZrO2, TCS + Nb2O5 and MTA (P < 0.05) than in the CG; no significant difference was detected after 60 days (P > 0.05). The width of the periodontal space and amount of collagen in TCS + ZrO2 and TCS + Nb2O5 groups were similar to the CG at 30 and 60 days while SG specimens had a significant reduction (P < 0.05) in the amount of collagen and significant increase (P < 0.05) in the width of the periodontal space.
Conclusions
TCS + ZrO2 and TCS + Nb2O5 were associated with periodontium repair since these materials allowed the reestablishment of periodontal space width and collagen formation when used in the filling of uninfected perforations in the pulp chamber floor of maxillary rat molars. Furthermore, the significant reduction in the periodontal space of TCS + ZrO2 and TCS + Nb2O5 specimens after 60 days confirmed that the experimental materials were associated with a more rapid recovery of the injured tissues than MTA.
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BFBNIB, CMK, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The RNA exosome is an evolutionarily conserved 3'-5' exoribonucleolytic protein complex involved in processing and degradation of different classes of nuclear and cytoplasmic RNAs, and, therefore, ...important for the posttranscriptional control of gene expression. Despite the extensive in vivo functional studies and the structural data on the RNA exosome, few studies have been performed on the localization and expression of exosome subunits during gametogenesis, process during which gene expression is largely controlled at the posttranscriptional level.
We report the identification of exosome subunits in Lithobates catesbeianus and analysis of the differential subcellular localization of RNA exosome core and catalytic subunits in testis cells. In addition, we show seasonal differences in the expression levels of four exosome subunits in different organs. In addition to being part of the RNA exosome complex, its subunits might participate independently of the complex in the control of gene expression during seasonal variation in bullfrog tissues. These results may be relevant for other eukaryotic species.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
da Silva GF, Guerreiro‐Tanomaru JM, Sasso‐Cerri E, Tanomaru‐Filho M, Cerri PS. Histological and histomorphometrical evaluation of furcation perforations filled with MTA, CPM and ZOE. International ...Endodontic Journal, 44, 100–110, 2011.
Aim To evaluate the biological response of the periodontium adjacent to furcation perforations in rat molars filled with Endo‐CPM‐Sealer (CPM), MTA‐Angelus (MTA) or zinc oxide–eugenol cement (ZOE).
Methodology The pulp chamber floors of maxillary right first molar teeth were perforated and sealed with CPM, mineral trioxide aggregate (MTA) or ZOE; the left first molars, without any treatment, were used as controls (CG). After 7, 15, 30 and 60 days, fragments of maxilla were fixed, decalcified and embedded in paraffin. Sections were stained with H&E, Masson’s trichrome and submitted to tartrate‐resistant acid phosphatase (TRAP) reaction, used as an osteoclast marker. The width of the periodontal space, the numerical density of inflammatory cells and the number of TRAP‐positive osteoclasts in the bone surface were measured, and statistical analyses were performed using analysis of variance and Tukey test (P ≤ 0.05).
Results In all experimental groups, the greatest number of inflammatory cells was observed at 7 days, especially in the ZOE group. In this group, the intense inflammatory process was related to a significant increase (P ≤ 0.05) in the number of osteoclasts and, thereby, in an increase in the width of the periodontal space. At 60 days, no significant differences in osteoclast numbers amongst CPM, MTA and CG groups occurred; the periodontal space was also significantly reduced in the experimental groups in comparison with the initial periods. However, in the ZOE group, the periodontal space was significantly larger (P ≤ 0.05) in comparison with MTA‐based materials.
Conclusions The periodontium adjacent to perforations filled with MTA and CPM exhibited clear evidence of re‐establishment and thus better biocompatibility than ZOE.
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BFBNIB, CMK, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The use of glycol methacrylate (GMA) avoids some technical artifacts, which are usually observed in paraffin-embedded sections, providing good morphological resolution. On the other hand, weak ...staining have been mentioned during the use of different methods in plastic sections. In the present study, changes in the histological staining procedures have been assayed during the use of staining and histochemical methods in different GMA-embedded tissues.
Samples of tongue, submandibular and sublingual glands, cartilage, portions of respiratory tract and nervous ganglion were fixed in 4% formaldehyde and embedded in glycol methacrylate. The sections of tongue and nervous ganglion were stained by H&E. Picrosirius, Toluidine Blue and Sudan Black B methods were applied, respectively, for identification of collagen fibers in submandibular gland, sulfated glycosaminoglycans in cartilage (metachromasia) and myelin lipids in nervous ganglion. Periodic Acid-Schiff (PAS) method was used for detection of glycoconjugates in submandibular gland and cartilage while AB/PAS combined methods were applied for detection of mucins in the respiratory tract. In addition, a combination of Alcian Blue (AB) and Picrosirius methods was also assayed in the sublingual gland sections.
The GMA-embedded tissue sections showed an optimal morphological integrity and were favorable to the staining methods employed in the present study. In the sections of tongue and nervous ganglion, a good contrast of basophilic and acidophilic structures was obtained by H&E. An intense eosinophilia was observed either in the striated muscle fibers or in the myelin sheaths in which the lipids were preserved and revealed by Sudan Black B. In the cartilage matrix, a strong metachromasia was revealed by Toluidine Blue in the negatively-charged glycosaminoglycans. In the chondrocytes, glycogen granules were intensely positive to PAS method. Extracellular glycoproteins were also PAS positive in the basal membrane and in the region occupied by the
lamina externa and reticular fibers surrounding each smooth muscle cells of the blood vessels. In the epithelial cells of the respiratory tract, acid and neutral mucins were histochemically detected by AB and PAS methods, respectively. Moreover, granules containing acid and neutral mucins were revealed in purple by AB and PAS concomitantly. In the sublingual gland sections, a distinct affinity of acid mucins by AB (in turquoise-blue) and collagen fibers by Picrosirius (in red) was obtained when these methods were combined. Although some routine dyes used in paraffin sections have showed a weak stain in historesin sections, our results showed that different dyes could be applied in GMA sections if modified staining procedures were assayed. Therefore, appropriate staining contrast and, thus, detection of one or different substances in a same section can be acquired in association to the good morphological resolution provided by GMA.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Background and Objective: Rests of Malassez are clusters of epithelial cells that remain in the periodontal ligament throughout life. However, it has been reported that the number of these ...structures decreases with age, and some epithelial cells undergo apoptosis in rests of Malassez of young and adult rats. Therefore, the purpose of the present study was to investigate the incidence of epithelial cell death and the quantitative changes in the rests of Malassez in rat molars of different ages.
Material and Methods: Fragments containing the upper molars of rats aged 29, 45 and 120 d were fixed, decalcified and embedded for analysis by light microscopy. In the sections stained by hematoxylin and eosin, the number of rests of Malassez and the number of nuclei of these epithelial structures were obtained. Moreover, the nuclei exhibiting typical features of cell death were also counted in each rest of Malassez. The terminal deoxynucleotidyl transferase‐mediated dUTP nick end labeling (TUNEL) method for detection of cell death was also carried out.
Results: In all groups examined, some rests of Malassez exhibited epithelial cell nuclei with typical features of apoptosis and some of them were also TUNEL positive. From 29 to 120 d of age in rats, the quantitative analysis showed a significant decrease in the total number of rests of Malassez in the cervical, middle and furcation regions of the periodontal ligament. Moreover, a significant decrease of epithelial cell nuclei was concomitant to an increase in the frequency of cell death in the oldest rats.
Conclusion: These results suggest that epithelial cell death by apoptosis may be, at least in part, responsible for the reduction in the number of rests of Malassez according to age.
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BFBNIB, CMK, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Background and Objective: Bone is a mineralized tissue that is under the influence of several systemic, local and environmental factors. Among systemic factors, estrogen is a hormone well known for ...its inhibitory function on bone resorption. As alveolar bone of young rats undergoes continuous and intense remodeling to accommodate the growing and erupting tooth, it is a suitable in vivo model for using to study the possible action of estrogen on bone. Thus, in an attempt to investigate the possibility that estrogen may induce the death of osteoclasts, we examined the alveolar bone of estrogen‐treated rats.
Material and Methods: Fifteen, 22‐d‐old female rats were divided into estrogen, sham and control groups. The estrogen group received estrogen and the sham group received corn oil used as the dilution vehicle. After 8 d, fragments containing alveolar bone were removed and processed for light microscopy and transmission electron microscopy. Sections were stained with hematoxylin and eosin and tartrate‐resistant acid phosphatase (TRAP)–an osteoclast marker. Quantitative analysis of the number of TRAP‐positive osteoclasts per mm of bone surface was carried out. For detecting apoptosis, sections were analyzed by the Terminal deoxynucleotidyl transferase‐mediated dUTP Nick‐End Labeling (TUNEL) method; TUNEL/TRAP combined methods were also used.
Results: The number of TRAP‐positive osteoclasts per mm of bone surface was significantly reduced in the estrogen group compared with the sham and control groups. TRAP‐positive osteoclasts exhibiting TUNEL‐positive nuclei were observed only in the estrogen group. In addition, in the estrogen group the ultrastructural images revealed shrunken osteoclasts exhibiting nuclei with conspicuous and tortuous masses of condensed chromatin, typical of apoptosis.
Conclusion: Our results reinforce the idea that estrogen inhibits bone resorption by promoting a reduction in the number of osteoclasts, thus indicating that this reduction may be, at least in part, a consequence of osteoclast apoptosis.
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BFBNIB, CMK, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In amphibia, steroidogenesis remains quiescent in distinct seasonal periods, but the mechanism by which spermatogenesis is maintained under low steroidogenic conditions is not clear. In the present ...study, testosterone location in the testes of Rana catesbeiana was investigated immunohistochemically during breeding (summer) and nonbreeding (winter) periods. In winter, the scarce interstitial tissue exhibited occasional testosterone immunopositivity in the interstitial cells but the cytoplasm of primordial germ cells (PG cells) was clearly immunopositive. By contrast, in summer, PG cells contained little or no immunoreactivity whereas strong immunolabelling was present in the well‐developed interstitial tissue. These results suggest that PG cells could retain testosterone during winter. This androgen reservoir could be involved in the control of early spermatogenesis in winter and/or to guarantee spermiogenesis and spermiation in the next spring/summer. The weak or negative immunoreaction in the summer PG cells might reflect consumption of androgen reservoir by the intense spermatogenic activity from spring to summer. Thus, besides acting as stem cells, PG cells of R. catesbeiana could exert an androgen regulatory role during seasonal spermatogenesis.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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