Hazardous effects of urban air particulate matter acute exposure on lung and extrapulmonary organs in mice.

Air particulate matter (PM) can lead to extrapulmonary adverse reactions in organs such as liver and heart either by particle translocation from the lung to the systemic circulation or by the release of lung mediators. Young BALB/c mice were intranasal instilled with 1mg/BW of Urban Air Particles from Buenos Aires or Residual Oil Fly Ash. Histopathology, oxidative metabolism and inflammation on lungs and extrapulmonary organs and the systemic response were evaluated. Lung histophatological analysis supported the rise in the number of inflammatory cells in the bronchoalveolar lavage from PM-exposed animals. Also, both PM caused recruitment of inflammatory cells in the liver and heart parenchyma and IL-6 and transaminases augmentation in serum. We have shown that despite morphochemical differences, both urban air PM altered the lung and extrapulmonary organs. Therefore, exposure to urban air PM may distress body metabolism which, in turn could lead to the development and progression of multifactorial diseases.

Effect of a mixture of GOS/FOS® on calcium absorption and retention during recovery from protein malnutrition: experimental model in growing rats.

INTRODUCTION: During growth, protein deprivation impairs epiphyseal growth plate (EGP) height, bone volume (BV) and endochondral ossification. During catch-up growth, Ca availability becomes essential to ensure the extra amount needed to achieve optimal peak bone mass and strength. GOS and FOS improve mineral absorption in the colon. PURPOSE: The effect of a mixture of GOS/FOS® 9:1 added to a 0.5 %Ca (NCa) and a 0.3 %Ca (LCa) diets on Ca, P and Mg absorptions and bone mineralization, density and structure using an experimental model of growing rats recovering from early protein malnutrition was investigated. METHODS: To induce protein malnutrition, rats were fed a low protein diet: 4 % (LPD) during 1 week and then were randomly assigned to recovery groups (R) until day 50 (T = 50) as follows: R0.5 %: NCa; RP0.5 %: NCa + 5.3 % GOS/FOS®; R0.3 %: LCa and RP0.3 %: LCa + 5.3 % GOS/FOS®. Control groups received the 0.5 %Ca or 0.3 %Ca diet from weaning until day 40 or 50. RESULTS: Body weight and length increased in C groups throughout the study; both were arrested in all R during LPD consumption and increased immediately after re-feeding. Independently of dietary Ca content, LS counts, ß-glucosidase and Ca, P and Mg absorption increased, whereas cecum pH, ß-glucuronidase, urease and tryptophanase decreased in RP0.5 %: and RP0.3 %: as compared to the other studied groups (p < 0.01). Prebiotic consumption decreased CTX levels and increased femur Ca, Mg and P contents, total skeleton bone mineral content, proximal tibia and spine BMD, BV, EGP height and hypertrophic zone thickness, stiffness and elastic modulus as compared to recovery groups fed the prebiotic-free diets. CONCLUSION: Under the present experimental conditions, GOS/FOS® mixture induced colonic positive effects, which increased Ca, P and Mg absorption. Thus, consuming the prebiotic-containing diet resulted in an extra amount of minerals that improved bone development in growing rats recovering from protein malnutrition.

Effect of alendronate on the mandible and long bones: an experimental study in vivo.

BACKGROUND: Bisphosphonates are anticatabolic agents that inhibit bone resorption and are widely used to treat osteoporosis and bone metastases in adults. They are also used in young patients with diseases like osteogenesis imperfecta or juvenile osteoporosis. Bone modeling/remodeling is elevated in growing subjects, and inhibition of osteoclastic activity has been shown to interfere with growth. Thus, our objective was to evaluate the effect of alendronate (ALN) on growing animals. METHODS: Healthy male Wistar rats, aged 1 mo, received ALN or vehicle for 8 wk. Serum levels (calcemia, phosphatemia, and total alkaline phosphatase) were determined. Morphometric (rat: femur and tibia weight and length and hemimandible growth) and histomorphometric parameters (thickness of tibial epiphyseal cartilage and each cartilage zone, interradicular bone volume in the first lower molar, trabeculae volume, percentage of bone and cartilage, and osteoclast number in mandibular condyles) were assessed. RESULTS: ALN caused a significant decrease in femur and tibia length, tibial cartilage thickness, and longitudinal growth of hemimandibles. It increased interradicular bone volume and mandibular condyle trabeculae volume, increasing the percentage of cartilage and osteoclast number. CONCLUSION: These findings indicate that administration of ALN to growing animals alters the endochondral ossification process, and thus alters growth.

Effect of a combination GOS/FOS® prebiotic mixture and interaction with calcium intake on mineral absorption and bone parameters in growing rats.

AIM: Increasing calcium intake is the most effective strategy for avoiding Ca deficit. However, if intake remains inadequate, improving Ca absorption becomes an important tool to optimize Ca homeostasis and bone health. PURPOSE: The effect of a mixture of GOS/FOS(®) 9:1 added to a normal- or low-Ca diets on Ca absorption and bone mineralization, density and structure was investigated, in a model of growing rats. Several colonic parameters to help support the findings were also evaluated. RESULTS: Weanling Wistar rats received one of the four experimental AIN-93G diets: C5: 0.5% Ca; C3: 0.3% Ca; P5: 0.5% Ca + 5.3% GOS/FOS(®); P3: 0.3% Ca + 5.3% GOS/FOS(®) until 50 days (T = 50). At T = 50, lactobacillus and cecum weights were higher, whereas cecum pH was lower in P5 and P3 versus C5 and C3 (p < 0.001). At T = 50, fecal Ca, Mg and P were lower and their absorptions (mg/dL) were higher in P5 and P3 versus C5 and C3, respectively (p < 0.05). Ca, Mg and P absorption % was higher in P5 and P3 versus C5 and C3 (p < 0.001). Femur Ca and P content, bone mineral content, trabecular bone mineral density, tibia length, bone volume, osteoblast surface, stiffness and elastic modulus were higher in P5 and P3 versus C5 and C3 (p < 0.05). Despite the lower Ca content, P3 group reached similar values than C5 in all these latter parameters. CONCLUSIONS: Supplementing diets with the GOS/FOS(®) mixture increased bone mineralization, density and structure due to an increase in Ca, P and Mg absorptions. Thus, this prebiotic mixture may help to improve bone development in a period of high calcium requirements.

Prenatal Exposure to Continuous Constant Light Alters Endochondral Ossification of the Tibiae of Rat Pups.

UNLABELLED: Clinical and experimental studies suggest that prenatal exposure to stress can impact the growth and development of offspring. The effect of prenatal exposure to constant light, applied as a chronic stressor, on endochondral ossification of the tibiae of 3-day-old and 15-day-old pups was histomorphometrically evaluated. Pregnant rats were divided into 2 groups: mothers chronically exposed to a 12:12-hour light/light cycle (LL) and control mothers maintained on a 12:12-hour light/dark cycle on days 10-20 of pregnancy. On postnatal days 3 and 15, the pups were weighed and euthanized. The tibiae were resected and histologically processed to obtain sections for hematoxylin and eosin staining (HE) and tartrate-resistant acid phosphatase (TRAP) histochemistry, in order to perform histomorphometric determinations. The data were statistically analyzed. A significant decrease in hypertrophic cartilage thickness was observed in the tibiae of the 3-day-old (LL: 0.134 ± 0.02 vs. CONTROLS: 0.209 ± 0.023 mm; p < 0.01) and 15-day-old (LL: 23.32 ± 3.98 vs. CONTROLS: 22.96 ± 1.93 mm; p < 0.05) prenatally stressed pups. The subchondral bone volume was significantly lower in the tibiae of the 3-day-old LL pups (38.83 ± 6.14%) than in the controls (62.83 ± 10.67%; p < 0.01). The decrease in subchondral bone volume and hypertrophic cartilage thickness shows that the normal growth process of the tibia is impaired in prenatally stressed pups.

Low protein intake magnifies detrimental effects of ovariectomy and vitamin D on bone.

Protein-induced changes in bone and calcium homeostasis could potentially be greater in the elderly and in women at risk for osteoporosis. We hypothesize that a low protein intake would magnify the negative changes in bone metabolism seen in vitamin D (vitD) insufficiency and/or estrogen deficiency. The present study was undertaken to better understand how a low protein diet along with vitD insufficiency could affect bone metabolism using a rodent ovariectomized (OVX) model. Rats (n = 60) underwent ovariectomy (OVX) or sham operation. The first 15 days after surgery, all rats were fed a standard rodent diet. Thereafter, rats (n = 10/group) were fed a low protein diet (LP; 2.5 %) or a control diet (NP; 12.5 %) with 100 IU% vitD (+D; cholecalciferol) or without vitD (-D) for 45 days. The groups were as follows: SHAM + NP + D (control); SHAM + LP + D; SHAM + LP - D; OVX + NP + D; OVX + LP + D; OVX + LP - D. Body weight (BW) of control and OVX + NP + D groups increased while those feeding the LP diet, independently of vitD feedings, decreased (p < 0.05). The OVX + LP - D group presented the lowest serum Ca, phosphorus and osteocalcin levels and the highest CTX levels (p < 0.05). At the end of the study, total skeleton bone mineral content, proximal tibia bone mineral density, bone volume and trabecular number levels decreased as follows: SHAM + NP + D (controls) > SHAM + LP + D > OVX + NP + D > SHAM + LP - D > OVX + LP + D > OVX + LP - D (p < 0.05). A low protein diet negatively affected bone mass and magnified the detrimental effects of vitD and/or estrogen deficiencies.

Histomorphometric study and three-dimensional reconstruction of the osteocyte lacuno-canalicular network one hour after applying tensile and compressive forces.

The occurrence of very early morphological changes in the osteocyte lacuno-canalicular network following application of tensile and/or compressive forces remains unknown to date. Thus, the aim of this study was to perform a morphological and morphometric evaluation of the changes in the three-dimensional structure of the lacuno-canalicular network and the osteocyte network of alveolar bone that take place very early after applying tensile and compressive forces in vivo, conducting static histomorphometry on bright-field microscopy and confocal laser scanning microscopy images. Our results showed that both the tensile and compressive forces induced early changes in osteocytes and their lacunae, which manifested as an increase in lacunar volume and changes in lacunar shape and orientation. An increase in canalicular width and a decrease in the width and an increase in the length of cytoplasmic processes were also observed. The morphological changes in the lacuno-canalicular and osteocyte networks that occur in vivo very early after application of tensile and compressive forces would be an indication of an increase in permeability within the system. Thus, both compressive and tensile forces would cause fluid displacement very soon after being applied; the latter would in turn rapidly activate alveolar bone osteocytes, enhancing transmission of the signals to the entire osteocyte network and the effector cells located at the bone surface.

High-fat diets affect energy and bone metabolism in growing rats.

BACKGROUND: High-fat diets are usually associated with greater weight (W) gain and body fat (BF). However, it is still unclear whether the type and amount of fat consumed influence BF. Additionally, dietary fat intake may also have consequences on skeletal health. OBJECTIVE: To evaluate in healthy growing rats the effects of high-fat diets and type of dietary fat intake (saturated or vegetable oils) on energy and bone metabolism. METHODS: At weaning, male Wistar rats (n = 50) were fed either a control diet (C; fat = 7% w/w) or a high-fat diet (20% w/w) containing either: soybean oil, corn oil (CO), linseed oil (LO), or beef tallow (BT) for 8 weeks. Zoometric parameters, BF, food intake and digestibility, and total and bone alkaline phosphatase (b-AP) were assessed. Total skeleton bone mineral density (BMD) and content (BMC), BMC/W, spine BMD, and bone volume (static-histomorphometry) were measured. RESULTS: Animals fed BT diet achieved lower W versus C. Rats fed high-fat vegetable oil diets showed similar effects on the zoometric parameters but differed in BF. BT showed the lowest lipid digestibility and BMC. In contrast, high vegetable oil diets produced no significant differences in BMC, BMC/W, BMD, spine BMD, and bone volume. Marked differences were observed for LO and BT groups in b-AP and CO and BT groups in bone volume. CONCLUSION: BT diet rich in saturated fatty acids had decreased digestibility and adversely affected energy and bone metabolisms, in growing healthy male rats. There were no changes in zoometric and bone parameters among rats fed high vegetable oil diets.

Effects of lead exposure on growth and bone biology in growing rats exposed to simulated high altitude.

The existence of children living at high altitude suffering from lead (Pb) poisoning prompted us to investigate the long term effects of this pollutant on growth and bone biology in growing rats maintained at simulated high altitude (SHA). Pb and hypoxia (HX) significantly reduced body weight (-9.4 % and -24 %; p < 0.01) and length (-3 % and -8 %; p < 0.01); decreased femoral ultimate load (-16 % and -40 %; p < 0.01) and femoral energy absorption capacity (-18 % and -74 %; p < 0.01). Oral pathologic alterations were observed in experimental groups. Our findings revealed growth retardation and damages on femoral and mandibular bones that predispose to fractures.

Lead bone toxicity in growing rats exposed to chronic intermittent hypoxia.

Lead chronic intoxication under hypoxic conditions revealed growth retardation in growing rats and damages on femoral and mandibular bones that predispose to fractures. These findings aimed us to investigate if bone material and geometric properties, bone mass in terms of histomorphometry or antioxidant capacity are also impaired in such experimental model. Combined treatments significantly reduced hemimandible cross sectional geometry and intrinsic stiffness (-16% and -34%); tibia and hemimandible bone volume (-45% and -40%) and growth plate cartilage thickness (-19%). These results show a previously unreported toxic effect of lead on mandible however, longer studies should be necessary to evaluate if an adaptation of bone architecture to maintain structural properties may occur and if the oxidative stress can be identified as the primary contributory agent in the pathogenesis of lead poisoning.

Effect of strontium ranelate on bone remodeling.

Osteoporosis is a disease in which the microarchitecture of bone tissue deteriorates, with consequent loss of bone mass. Strontium ranelate (SrR) is currently used for treatment of the condition. SrR may have a dual effect: anabolic (stimulating pre-osteoblast replication) and anti-catabolic (reducing osteoclastic activity). However, its mechanism of action has not yet been completely elucidated. The aim of this study is to evaluate the effect of SrR on bone remodeling in healthy Wistar rats. Two-month old female Wistar rats were administered SrR (2 g/L) in drinking water for 30 weeks. Oriented histological sections were prepared from lower jaw and tibia and stained with H&E, and the following histomorphometric parameters were evaluated: a) in interradicular bone: bone volume, and percentages of bone-formation, quiescent and bone-resorption surfaces; and b) in tibia: bone volume, total thickness of growth cartilage, thickness of hypertrophic cartilage zone and number of megakaryocytes. No significant difference was found in the parameters between the control animals and those treated with SrR. The results would therefore show that SrR does not alter the bone parameters studied in this experimental design.

Epithelial rests of Malassez in experimental animals at different ages.

Epithelial rests of Malassez (ERMs) are fragments of Hertwig's sheath in the periodontal ligament. There is extensive knowledge of their role in the etiology ofpathological processes and current evidence links them to maintenance of periodontal homeostasis. The aim of this study was to assess the behavior of ERMs with relation to the changes in periodontal tissues during growth in an experimental model with Wistar rats. Mesiodistal sections were made of the first lower molars from Wistar rats aged 1 month (n=7), 3 months (n=7) and 5 months (n=6). Sections were stained with H&E to evaluate number of ERMs/ mm, size/area of ERMs (pm2), height of periodontal ligament (PL.h) (pm), area of cement in the furcation zone (C.Ar) (pm2) and bone area related to the ERM zone (BAr/TAr)(%). Posthoc Bonferroni and ANOVA were applied for statistical analysis of results. Number of ERMs/mm declined significantly with age (1m: 4.34±1.51, 3m: 1.48±0.89, 5m: 0.27± 0.50, p<0.05), and there was great variability in size. There was significant increase in C.Ar (1m: 3418.96 ± 905.88, 3m: 19365.76 ± 5500.52, 5m: 32182.76 ± 7114.51, p< 0.05) and interradicular (BAr/TAr) (1m: 25.26 ± 2.37, 3m: 44.70 ± 3.95, 5m: 46.81 ± 7.80, p< 0.05: 1 vs 3, 1 vs 5). There was significant decline in PLh at 5 months (1m: 141.42 ± 29.25, 3m: 162.06 ± 28.21, 5m: 124.72 ± 18.67, p< 0.05: 1 vs. 3, 3 vs. 5). The decline in number of ERMs as animal age increases may be related to the significant increase in C.Ar and reduction in PL.h. It remains to ascertain its relationship with the increase observed in BAr/ TAr. Further studies are needed to learn more about the role of ERMs and their relationship with periodontal tissues when confronted with different normal and pathological stimuli.

Los restos epiteliales de Malassez (ERMs) son fragmentos de la vaina de Hertwig, en el ligamento periodontal. Se conoce extensamente su rol en la etiología de procesos patológicos y actualmente las evidencias los vinculan al mantenimiento de la homeostasis periodontal. El objetivo del presente trabajo fue evaluar el comportamiento de los ERMs en relación a los cambios de los tejidos periodontales durante el crecimiento en un modelo experimental de ratas Wistar. Se obtuvieron cortes mesio-distales del 1er molar inferior de ratas Wistar de 1 mes (n=7), 3 meses (n=7) y 5 meses (n=6) de edad. En cortes coloreados con H&E, se evalúo: N° de ERMs/mm, tamaño/ área de ERMs (pm2), altura del ligamento periodontal (PL.h) (pm), área de cemento en la zona de furcación (C.Ar) (pm2) y área del hueso relacionado con la zona de los ERMs (BAr/TAr) (%). Los resultados se analizaron estadísticamente mediante ANOVA y Bonferroni post-hoc. El N° de ERMs/mm disminuyó significativamente con la edad (1m: 4.34±1.51, 3m: 1.48±0.89, 5m: 0.27± 0.50, p<0.05), observándose una gran variabilidad de tamaño. Se observó un aumento significativo del CAr (1m: 3418.96 ± 905.88, 3m: 19365.76 ± 5500.52, 5m: 32182.76 ± 7114.51, p< 0.05) y del (BAr/TAr). interradicular (1m: 25.26 ± 2.37, 3m: 44.70 ± 3.95, 5m: 46.81 ± 7.80, p< 0.05: 1 vs 3, 1 vs 5). Además, se halló una disminución significativa en PLh a los 5 meses (1m: 141.42 ± 29.25, 3m: 162.06 ± 28.21, 5m: 124.72 ± 18.67, p< 0.05: 1 vs 3, 3 vs 5). La disminución hallada del número de ERMs conforme aumenta la edad del animal podría vincularse con el aumento significativo del C.Ar y la reducción del PL.h. Resta por dilucidar su relación con el aumento de BAr/TAr. observado. Se requieren más estudios para profundizar sobre el rol de los ERMs y su relación con los tejidos periodontales ante distintos estímulos normales y patológicos.

Evaluation of vascular endothelial growth factor (VEGF) in interradicular bone marrow in olpadronate treated animals.

UNLABELLED: Vascular endothelial growth factor (VEGF) is a protein that increases vascular permeability and induces the proliferation, migration and survival of endothelial cells. Bisphosphonates (BPs) are antiresorptive drugs that are widely used in the treatment of bone metabolism diseases and bone metastases. Since 2003, cases of bisphosphonate-related osteonecrosis of the jaw (BRONJ) have been reported. Few papers explain the mechanisms that induce BRONJ; some authors mention alterations in bone remodelling and a certain antiangiogenic effect of BPs. The aim of this study is to evaluate the expression of VEGF in bone marrow cells and the number of blood vessels and area occupied by them in animals treated with the BP sodium olpadronate (OPD). We used 16 Wistar rats, 60 days old, divided into two groups, experimental (OPD) and control. The OPD group received 0.3 mg/kg/week intraperitoneal OPD for 5 weeks. The control group received an equivalent intraperitoneal volume of physiological saline solution. After euthanasia, hemimandibles were processed and mesio-distal histological sections of the first molar were prepared. Sections were stained with hematoxylin-eosin (HE), immunohistochemical detection of VEGF was performed (sc-7269) and the following histomorphometric parameters were evaluated: In HE-stained sections--number of blood vessels per sq. mm. and percentage (%) of area occupied by blood vessels in relation to total area evaluated; in sections with immunohistochemical detection of VEGF--number of VEGF+ bone marrow cells per sq. mm. Data underwent statistical analysis. Number of blood vessels/mm2 was significantly lower in the OPD group (OPD: 92 +/- 16; CONTROL: 140 +/- 31; p < 0.05) and % vascular area/total area evaluated showed no significant difference (OPD: 15.6 +/- 6.1; CONTROL: 10.2 +/- 4.2). Number of VEGF+ cells/mm2 was lower in the OPD group than in the control group, with statistically significant differences (OPD: 7804.8 +/- 597; CONTROL: 13187.6 +/- 894; p < .001). The results of this study suggest that monosodium olpadronate has an antiangiogenic effect. Further studies are needed to reveal its potential as an antitumor agent and its connection with the onset of BRONJ.

Fish oil diet effects on alveolar bone loss, in hypercholesterolemic rats.

This study evaluated the effects of replacing a saturated fat diet by n-3 polyunsaturated fatty acids (n-3PUFA), on alveolar bone loss in hypercholesterolemic rats with experimental periodontitis (PD). METHODS: Eight week old Wistar rats were assigned according to dietary intake. Control group (C, n = 15) fed a commercial diet throughout the experiment. Atherogenic group (AT, n = 30) fed AT diet for 3 weeks; thereafter, AT was randomized to receive either a n-3PUFA (n = 15) or to continue with AT (n = 15) diet. Subsequently, PD was induced in all groups by unilateral ligature (L) of the first molar (M1) of the left mandible, non-ligated contralateral molars served as controls. After every week of PD induction, 5 rats per group were euthanized. Serum was collected for lipids assays and hemi-mandibles were subjected to histomorphometric (% upper and lower interradicular bone volume and periodontal ligament height, hPDL) and radiographic analyses (periodontal bone support, PBS, in ligated teeth, between M1-M2). RESULTS: Rats fed n-3PUFA diet rapidly induced a significant reduction in the serum lipids (p < 0.001). In all rats the ligated teeth showed a greater bone loss as compared with the unligated molars. At the end of the experiment the AT + L was the worst in % lower bone volume (p < 0.01), hPDL and PBS (p < 0.05). In contrast, rats fed n-3PUFA + L was similar to those rats fed C diet (p > 0.05). CONCLUSION: Alveolar bone and dyslipidemia improved by substituting saturated fat intake for a n-3PUFA rich diet, in hypercholesterolemic rats with PD.

Improved bone status by the beta-blocker propranolol in an animal model of nutritional growth retardation.

The aim of the present research was to study if the beta-blocker propranolol, which is known to increase bone mass, could reverse the adverse skeletal effects of mild chronic food restriction in weanling rats. Male Wistar rats were divided into four groups: control, control+propranolol (CP), nutritional growth retardation (NGR) and nutritional growth retardation+propranolol (NGRP). Control and CP rats were fed freely with the standard diet. NGR and NGRP rats received, for 4 weeks, 80 % of the amount of food consumed by the control and CP rats, respectively. Results were expressed as mean values and sem. Food restriction induced detrimental effects on body and femur weight and length (P < 0.05) and bone structural and geometrical properties (P < 0.001), confirming results previously shown in our laboratory. However, the beta-blocker overcame the deleterious effect of nutritional stress on load-bearing capacity, yielding load, bone stiffness, cross-sectional cortical bone area and second moment of inertia of the cross-section in relation to the horizontal axis without affecting anthropometric, histomorphometric and bone morphometric parameters. The results suggest that propranolol administration to mildly chronically undernourished rats markedly attenuates the impaired bone status in this animal model of growth retardation.

Histological evaluation of subepithelial connective tissue grafts harvested by two different techniques: Preliminary study in humans.

Subepithelial connective tissue graft (SCTG) is an essential therapeutic tool in periodontal plastic surgery and implantology. The aim of this preliminary study was to observe and make a histological and histomorphometric comparison of the composition of subepithelial connective tissue grafts (SCTGs) harvested from the palatal mucosa by two different harvesting techniques: mucoperiosteal (lamina propria and complete submucosa including periosteum) and mucosal (lamina propria and a portion of the submucosa). The main hypothesis proposes that SCTG harvested with the mucosal technique contains a greater proportion of connective tissue proper (CTP) and a lower proportion of adipose tissue (AT) than the mucoperiosteal technique. Twenty healthy patients who required SCTG for different purposes were selected and assigned to one of the two following groups: group A (n=10; mucoperiosteal harvesting technique) and group B (n=10, mucosal harvesting technique). The histological sample was obtained by removing a 2 mm thick slice from the most distal portion of the graft. The proportions of adipose tissue (AT), connective tissue proper (CTP) and vascular tissue (VT) were evaluated. In group A, histomorphometric analysis showed that CTP accounted for 58.2% of the graft while AT accounted for 32.64%. In group B, the proportions of CTP and AT were 79.86% and 11.93%, respectively. The differences between groups were statistically significant for both tissues (p< .05). In contrast, no statistically significant difference was observed in the proportion of VT. Within the limitations of this study, the results show that the SCTGs harvested by the mucosal technique contain a greater proportion of CTP and a lower proportion of AT than those obtained by the mucoperiosteal technique, whereas the proportion of VT does not differ. Further long-term clinical and histological studies with more samples are needed to evaluate the clinical implications of SCTG composition.

El injerto de tejido conectivo subepitelial (ITCSE) es una herramienta indispensable en la cirugía plástica periodontal y la implantología. El objetivo del presente estudio preliminar fue observar y comparar histológica e histomorfometricamente la composición de los injertos de tejido conectivo subepitelial (ITCSE) obtenidos de la mucosa palatina mediante dos técnicas diferentes: mucoperióstica (lamina propia y submucosa incluyendo el periostio) y mucosa (lámina propia y parte de la submucosa). La principal hipótesis postula que el ITCSE obtenido mediante la técnica mucosa contiene mayor proporción de tejido conectivo propiamente dicho (TCP) y menor proporción de tejido adiposo (TA) que el obtenido mediante la técnica mucoperióstica. El presente estudio incluyó veinte pacientes sanos que requerían ITCSE por diferentes motivos, los cuales fueron distribuidos de forma equitativa en dos grupos: grupo A (n=10; técnica de obtención mucoperióstica) y grupo B (n=10; técnica de obtención mucosa). La muestra histológica se obtuvo removiendo una porción de 2 mm de ancho de la parte más distal del injerto. Se evaluó la proporción (%) de tejido adiposo (TA), tejido conectivo propiamente dicho (TCP) y tejido vascular (TV). En el grupo A, el análisis histomorfométrico mostró que el TCP constituía el 58.2% del tejido mientras que el tejido adiposo constituía el 32.64%. En el grupo B, la proporción de TCP y AT fue 79.86%y 11.93%, respectivamente. Las diferencias observadas entre los grupos fueron estadísticamente significativas para ambos tejidos (p< .05). En cambio, no se observaron diferencias estadísticamente significativas en la proporción de TV. Dentro de las limitaciones del presente estudio, los resultados mostraron que los ITCSE obtenidos mediante la técnica mucosa contienen mayor proporción de TCP y menor proporción de TA que los obtenidos con la técnica mucoperióstica, mientras que el TV permanece estable. Se requieren estudios longitudinales clínicos e histológicos a largo plazo con mayor cantidad de muestras para evaluar las implicancias clínicas de la composición del ITCSE.

Chronic exposure to urban air pollution from Buenos Aires: the ocular mucosa as an early biomarker.

Air pollution represents a major health problem in megacities, bringing about 8 million deaths every year. The aim of the study was to evaluate in vivo the ocular and respiratory mucosa biological response after chronic exposure to urban air particles from Buenos Aires (UAP-BA). BALB/c mice were exposed to UAP-BA or filtered air for 1, 6, 9, and 12 months. After exposure, histology, histomorphometry, and IL-6 proinflammatory cytokine level were evaluated in the respiratory and ocular mucosa. Total cell number and differential cell count were determined in the brochoalveolar lavage fluid. In the lung, chronic exposure to UAP-BA induced reduction of the alveolar space, polymorhonuclear cell recruitment, and goblet cell hyperplasia. In the ocular surface, UAP-BA induced an initial mucin positive cells rise followed by a decline through time, while IL-6 level increased at the latest point-time assayed. Our results showed that the respiratory and the ocular mucosas respond differently to UAP-BA. Being that lung and ocular mucosa diseases may be triggered and/or exacerbated by chronic exposure to urban air PM, the inhabitants of Buenos Aires whom are chronically exposed to environmental urban air pollution may be considered a subpopulation at risk. Based on our results, we propose the ocular mucosa as a reliable and more accessible surrogate for pulmonary mucosa environmental toxicity that might also serve as an earlier biomarker for air pollution adverse impact on health.

Influence of submandibulectomy on alveolar bone loss in rats.

BACKGROUND: The incidence of dry mouth and its public health impact are increasing as the result of a progressively larger, medicated older population and because chronic diseases, like periodontitis, are prevalent pathologies among elderly patients. Periodontitis and continuous remodeling and rebuilding alveolar processes greatly affect the margin of the alveolar bone, and there is evidence indicating the role of submandibular glands in the regulation of immune/inflammatory reactions. The purpose of this study was to assess the effect of submandibular-sublingual complex ablation (Sx) on alveolar bone loss in rats submitted or not to ligature-induced experimental periodontal disease (EP). METHODS: Wistar male rats were submitted to Sx or sham operations (day 0). Two weeks later, unilateral EP was induced on the right mandibular first molars for 7 days with the contralateral side serving as control. Bone loss at the level of the dental pieces was estimated by bone histomorphometry on mesio-distally oriented sections of the molars and by the determination on lingual and vestibular mandibular surfaces of the distances from the cemento-enamel junction to the alveolar crest. RESULTS: Sx and EP significantly increased lingual and vestibular alveolar bone loss. Molars with EP exhibited greater lingual loss in Sx animals compared to those with the sham operation. EP induced similar interradicular bone loss in sham and Sx rats. CONCLUSION: Sx has a deleterious effect on the periodontal tissues, particularly marginal alveolar bone, indicating the importance of the submandibular/sublingual glands in maintaining healthy periodontal conditions.

A Review of Metal Exposure and Its Effects on Bone Health.

The presence of metals in the environment is a matter of concern, since human activities are the major cause of pollution and metals can enter the food chain and bioaccumulate in hard and soft tissues/organs, which results in a long half-life of the metal in the body. Metal intoxication has a negative impact on human health and can alter different systems depending on metal type and concentration and duration of metal exposure. The present review focuses on the most common metals found in contaminated areas (cadmium, zinc, copper, nickel, mercury, chromium, lead, aluminum, titanium, and iron, as well as metalloid arsenic) and their effects on bone tissue. Both the lack and excess of these metals in the body can alter bone dynamics. Long term exposure and short exposure to high concentrations induce an imbalance in the bone remodeling process, altering both formation and resorption and leading to the development of different bone pathologies.

Evaluation of apoptosis and osteopontin expression in osteocytes exposed to orthodontic forces of different magnitudes.

The in vivo response of osteocytes to different force magnitudes soon after they are applied remains to be elucidated. The aim of this study was to examine the early effects of applying a very light (LF: 0,16 N) and a very strong (SF: 2,26 N) orthodontic force during one hour on apoptosis and osteopontin (OPN) expression on alveolar bone osteocytes, in rats. Results: LF: compared to the control group, they showed a significant increase in OPN expression, and a significant decrease in the number of TUNELpositive osteocytes. SF: compared to the control group, they showed a significant increase in OPN expression and a significant decrease in the number of TUNELpositive osteocytes. Our results show that osteocytes respond very early to the application of tension and pressure forces of different magnitudes, and application of forces decreases the number of apoptotic osteocytes and increases OPN expression. These results allow concluding that osteocytes activate rapidly when subjected to locally applied forces, whether these forces be pressure or tension, light or strong forces.

Hasta el momento no se ha dilucidado la respuesta temprana in vivo de los osteocitos a la aplicación de fuerzas de diferentes magnitudes sobre el hueso. El objetivo de este estudio fue examinar la respuesta temprana de la aplicación de una fuerza ortodóncica muy liviana (FL: 0,16 N) y muy fuerte (FF: 2,26 N) durante una hora sobre la expresión de apoptosis y osteopontina (OPN) en los osteocitos del hueso alveolar, en ratas. Resultados: FL: en comparación con el grupo control, mostraron un aumento significativo en la expresión de OPN y una disminución significativa en el número de osteocitos TUNELpositivos. FF: en comparación con el grupo control, mostraron un aumento significativo en la expresión de OPN y una disminución signi ficativa en el número de osteocitos TUNELpositivos. Nuestros resultados muestran que los osteocitos responden muy temprano a la aplicación de fuerzas de tensión y presión de diferentes magnitudes, y la aplicación de fuerzas disminuye el número de osteocitos apoptóticos y aumenta la expresión de OPN. Estos resultados permiten concluir que los osteocitos se activan rápidamente cuando se los somete a fuerzas aplicadas localmente, ya sean estas fuerzas de presión o tensión, livianas o fuertes.