ABSTRACT
Objectives: To study the effects of Porphyromonas gingivalis (Pg) injected through tail vein on the molecular expression levels of biomarkers of neural stem cells (NSC) and neurons in the hippocampus of wild-type adult rats, and the effects on hippocampal neurogenesis. Methods: Eighteen male Sprague-Dawley (SD) rats were randomly divided into 3 groups based on the table of random numbers (n=6 in each group). In low-intensity group and high-intensity group, rats were injected intravenously through tail vein with 200 μl Pg ATCC33277 [1.0×103 and 1.0×108 colony forming unit (CFU), respectively] 3 times per week for 8 weeks. In the sham group, 200 μl of phosphate buffer saline (PBS) was given instead. Behavioral tests: the navigation and the exploration tests using Morris water maze (MWM) were applied to evaluate learning and memory ability of rats. Immunohistochemistry was performed to detect cells positively expressing nestin, doublecortin (DCX) and neuronal nuclei (NeuN) in the subgranular zone (SGZ) of rats in each group. Western blotting was used to evaluate the expression levels of nestin, DCX and NeuN in rat hippocampus. Results: Learning and memory abilities: on day 5 of navigation test, the lagency time was 22.83 (16.00, 38.34) s in the high-intensity group, significantly longer than the sham group [5.59 (5.41, 6.17) s] (t=-11.17, P<0.001). There were no significant differences between the low-intensity group [9.85 (8.75, 21.01) s] and the sham group (t=-6.83, P=0.080). Results in the exploration test showed that, in the high-intensity group, the number of fime crossing over the previous platform area within 60 s was 1.50 (1.00, 2.00), significantly less than the sham group [4.00 (2.75, 4.00)] (t=9.75, P=0.003); no significant differences between the low-intensity group [2.50 (2.00, 3.00)] and the sham one (t=4.50, P=0.382). Immunohistochemistry showed that the nestin+ cell density in the low-intensity group [(35.36±4.32) cell/mm2] and high-intensity group [(26.51±5.89) cell/mm2] were significantly lower than the sham group [(59.58±14.15) cell/mm2] (t=24.21, P=0.018; t=33.07, P=0.005); as for the mean absorbance of DCX+ cells, the low-intensity group (0.007±0.002) and the high-intensity group (0.006±0.002) were significantly lower than the sham group (0.011±0.001) (t=0.004, P=0.018; t=0.006, P=0.005); compared with the sham group [(1.13±0.14)×103 cell/mm2], the density of NeuN+ neurons in the high-intensity group [(0.75±0.08)×103 cell/mm2] was significantly reduced (t=0.38, P=0.017), and was not significantly changed in the low-intensity group [(0.88±0.19)×103 cell/mm2] (t=0.25, P=0.075). Western blotting results showed that, compared with the sham group, the expression levels of nestin, DCX, and NeuN were significantly reduced in the high-intensity group (t=0.74, P<0.001; t=0.18, P=0.014; t=0.35, P=0.008), but were not statistically changed in the low-intensity group (t=0.18, P=0.108; t=0.08, P=0.172; t=0.19, P=0.077). Conclusions: Pg injected through tail vein may reduce learning and memory abilities of wild-type rats, and may reduce the number of nestin, DCX, and NeuN-positive cells, and the protein expression levels of the above molecules in the hippocampus.
Subject(s)
Animals , Male , Rats , Biomarkers/metabolism , Hippocampus/metabolism , Nestin/metabolism , Neural Stem Cells/metabolism , Neurons/metabolism , Porphyromonas gingivalis/metabolism , Rats, Sprague-Dawley , Tail/metabolismABSTRACT
The failure of fusion of nasal and maxillary processes results in cleft lip and palate (CLP), which is one of the most common birth defects. The morphopathogenesis of this pathology is multifactorial and still largely unclear. The aim of this study was to evaluate the presence of nestin, transcriptor factor SOX3 (Sox3) and homeobox protein DLX-4 (Dlx-4) in complete unilateral (CU) and complete bilateral (CB) CLP affected facial tissue. Oral mucosa tissue samples were obtained from 17 CUCLP and 13 CBCLP patients during surgical cleft correction and 6 unaffected control subjects. Obtained tissue sections were stained with hematoxylin and eosin and by immunohistochemistry for nestin, Sox3 and Dlx-4. The intensity of staining was graded semiquantitatively. Nestin-positive structures were detected in all CUCLP and CBCLP patients' tissue samples, varying from moderate number of nestin-positive structures to numerous. Sox3 immunoreactivity was more prominent in epithelial cells in both patient groups with frequently patchy distribution. Mainly moderate number of Dlx-4-positive cells was observed in most of tissue samples. Statistically significant moderate positive correlation was found between nestin and Sox3 factors in CUCLP patient group (Spearman's rank correlation coefficient = .517, P = .034). Increase of nestinpositive structures suggests its role in the regulation of the remodeling of tissue in both CUCLP and CBCLP affected tissue. Dominance of Sox3 positivity in cleft affected epithelium indicates its possible role in (compensatory) formation of defective oral epithelium of CUCLP and CBCLP patients. The reduced expression of Dlx-4 implicates its limited regulatory role on the craniofacial development in CUCLP and CBCLP affected tissue.
La falla en la fusión de los procesos nasal y maxilar son causante de la fisura labiopalatina (FLP), que es uno de los defectos congénitos más comunes. La morfopatogenia de esta patología es multifactorial y aún poco clara. El objetivo de este estudio fue evaluar la presencia de nestina, el factor transcriptor SOX3 (Sox3) y la proteína homeobox DLX-4 (Dlx-4) en todo el tejido facial afectado por FLP bilateral unilateral (FU) y bilateral completa (FB). Se obtuvieron muestras de tejido de mucosa oral de 17 pacientes FUFLP y 13 FBFLP durante la corrección quirúrgica de la fisura y de 6 sujetos de control no afectados. Las secciones de tejido obtenidas se tiñeron con hematoxilina y eosina y mediante inmunohistoquímica para nestina, Sox3 y Dlx-4. La intensidad de la tinción fue graduada semicuantitativamente. Se detectaron estructuras positivas para nestina en todas las muestras de tejido de pacientes FUFLP y FBFLP, variando desde un número moderado a numerosas estructuras positivas para nestina. La inmunorreactividad de Sox3 fue más prominente en las células epiteliales en ambos grupos de pacientes con distribución frecuentemente irregular. Se observó un número principalmente moderado de células Dlx-4-positivas en la mayoría de las muestras de tejido. Se encontró una correlación positiva moderada estadísticamente significativa entre los factores de nestina y Sox3 en el grupo de pacientes FUFLP (coeficiente de correlación de rangos de Spearman = 0,517, P = 0,034). El aumento de estructuras positivas para nestina sugiere su papel en la regulación de la remodelación de tejido, tanto en tejido afectado por FUFLP como FBFLP. La dominancia de la positividad de Sox3 en el epitelio afectado de la fisura, indica su posible papel en la formación (compensatoria) del epitelio oral defectuoso de pacientes FUFLP y FBFLP. La expresión reducida de Dlx-4 implica su función reguladora limitada en el desarrollo craneofacial en tejido afectado por FUFLP y FBFLP.
Subject(s)
Cleft Lip/metabolism , Cleft Palate/metabolism , Homeodomain Proteins/metabolism , SOXB1 Transcription Factors/metabolism , Nestin/metabolism , ImmunohistochemistryABSTRACT
It is considered that healthy adult cartilage has little or no capacity for renewal, and that chondrocytes maintain a stable resting phenotype and resist proliferation and differentiation throughout life. Recently we found that cell turnover in lung cartilage is possible and that nestin-positive cells may have a role in it. In this paper, we report additional findings about chondrocyte renewal in lung cartilage. Lung specimens from CD1 mice at the age of 2, 6, 12, 18 or 24 months were fixed in 10% neutral-buffered formalin and paraffin-embedded. Nestin expression was examined by an immunohistochemical peroxidase-based method. We found nestin-positive cells inside of cartilage islets and cells in division very close from them. Our findings indicate that there exist nestin-positive mesenchymal stem cells in the adult that are able to differentiate into lung chondrocytes, perhaps to maintain homeostasis or repair damaged tissue. These findings may improve our knowledge about the cartilage biology and could provide new cell candidates for cartilage tissue engineering.
Se considera que el cartílago adulto sano tiene poca o ninguna capacidad para renovarse, y que sus condrocitos permanecen en un estado de reposo estable, careciendo de las propiedades de proliferación y diferenciación. Recientemente encontramos que el recambio celular en el cartílago pulmonar es posible y que células troncales positivas para nestin pudieran tener algún papel en el mismo. En este artículo, reportamos nuevos hallazgos acerca de la renovación de condrocitos en el cartílago pulmonar. Pulmones de ratones CD1 de 2, 6, 12, 18 o 24 meses de edad se fijaron en formalina amortiguada al 10% y se incluyeron en parafina. Se analizó la expresión de nestin utilizando un método inmunohistoquímico basado en un sistema de detección con peroxidasa. Encontramos células positivas para nestin en el interior de los islotes de cartílago y células en división muy cercanas a ellas. Estos hallazgos indican que existen células madre mesenquimales positivas para nestin en el adulto con capacidad para diferenciarse en condrocitos pulmonares, probablemente para mantener la homeostasis tisular o reparar daños en el tejido. Asimismo, estos hallazgos pueden aumentar nuestra comprensión acerca de las propiedades biológicas del cartílago y podrían proporcionar nuevos candidatos para la ingeniería celular en la terapia regenerativa en enfermedades de las articulaciones.