ABSTRACT
ABSTRACT Nanotubes with their unique properties have diversified mechanical and biological applications. Due to similarity of dimensions with extracellular matrix (ECM) elements, these materials are used in designing scaffolds. In this research, Carboxylated Single-Wall Carbon Nanotubes in optimization of decellularized scaffold of bovine articular cartilage was used. At first, the articular cartilage was decellularized. Then the scaffolds were analyzed in: (i) decellularized scaffolds, and (ii) scaffolds plunged into homogenous suspension of nanotubes in distilled water, were smeared with Carboxylated-SWCNT. The tissue rings derived from the rabbit's ear were assembled with reinforced scaffolds and they were placed in a culture media for 15 days. The scaffolds in two groups and the assembled scaffolds underwent histologic and electron microscopy. Scanning electron microscopy showed that the structure of ECM of articular cartilage has been maintained well after decellularization. Fourier transform infrared analysis showed that the contents of ECM have not been changed under treatment process. Atomic force microscopy analysis showed the difference in surface topography and roughness of group (ii) scaffolds in comparison with group (i). Transmission electron microscopy studies showed the Carboxylated-SWCNT bond with the surface of decellularized scaffold and no penetration of these compounds into the scaffold. The porosity percentage with median rate of 91.04 in group (i) scaffolds did not have significant difference with group (ii) scaffolds. The electron microscopy observations confirmed migration and penetration of the blastema cells into the group (ii) assembled scaffolds. This research presents a technique for provision of nanocomposite scaffolds for cartilage engineering applications.
ABSTRACT
The effects of a high estradiol dose on memory and on nitric oxide metabolites in hippocampal tissues were investigated. Sham-Est and OVX-Est Groups were treated with 4 mg/kg of estradiol valerate for 12 weeks. Time latency and path length were significantly higher in the Sham-Est and OVX-Est Groups than in the Sham and OVX Groups, respectively (p<0.001). The animals in the Sham-Est and OVX-Est Groups spent lower time in the target quadrant (Q1) than those of the Sham and OVX Groups during the probe trial test (p<0.05 and <0.001, respectively). Significantly lower nitric oxide metabolite levels in the hippocampi of the Sham-Est and OVX-Est Groups were observed than in the Sham and OVX ones (p<0.001). These results suggest that decreased nitric oxide levels in the hippocampus may play a role in the learning and memory deficits observed after treatment with a high dose of estradiol, although the precise underlying mechanisms remain to be elucidated.
Os efeitos de uma alta dose de estradiol na memória e nos metabólitos do óxido nítrico de tecidos hipocampais foram estudados. Os Grupos Sham-Est e OVX-Est foram tratados com 4 mg/kg de valerato de estradiol por 12 semanas. O tempo de latência e o comprimento do caminho foram significativamente maiores nos Grupos Sham-Est e OVX-Est em relação aos Grupos Sham e OVX, respectivamente (p<0,001). Os animais dos Grupos Sham-Est e OVX-Est passaram menos tempo na meta do quadrante (Q1) do que aqueles dos Grupos Sham e OVX durante o teste inicial (p<0,05 e <0,001, respectivamente). Níveis significativamente menores de metabólitos do óxido nítrico foram observados nos hipocampos dos Grupos Sham-Est e OVX-Est em relação aos Grupos Sham e OVX (p<0,001). Esses resultados sugerem que os níveis diminuídos de óxido nítrico no hipocampo podem ter um papel nos déficits de aprendizado e de memória, que são observados após tratamento com alta dose de estradiol, embora os mecanismos específicos envolvidos nestes achados ainda precisam ser elucidados.
Subject(s)
Animals , Female , Humans , Rats , Contraceptive Agents/administration & dosage , Estradiol/analogs & derivatives , Hippocampus/metabolism , Learning Disabilities/etiology , Memory Disorders/etiology , Nitric Oxide/metabolism , Analysis of Variance , Dose-Response Relationship, Drug , Estradiol/administration & dosage , Hippocampus/drug effects , Learning Disabilities/metabolism , Maze Learning/drug effects , Memory Disorders/metabolism , Memory/drug effects , Nitric Oxide/biosynthesis , Ovariectomy , Random Allocation , Rats, WistarABSTRACT
Stimulation of peripheral nociceptors leads to releasing of some mediators such as substance P (SP) and Calcitonin gene-related peptide (CGRP) and contributes to the edema formation by vasodilatation induction. On the other hand glucocorticoids have anti-inflammatory action, and they are elevated in the plasma during stress. This communication reports C-fibers inflammatory role and the effects of chronic and acute stress and/or dexamethasone (as stress mimicry) on paw edema induced by formalin at presence/deficit C-fibers rats. Acute stress and dexamethasone and chronic dexamethasone have shown an anti-inflammatory effect in C-normal groups, but chronic stress had no effect on inflammation. C-fibers reduction (C-lesion) had anti-inflammatory effects. In deficit C-fibers rats, acute and chronic stress had not stronger anti-inflammatory effect, but acute dexamethasone reduced the anti-inflammatory effect of C-fibers reduction while in the same condition, chronic dexamethasone induced stronger anti-inflammatory effect. The results show C-fiber nerve produce and release the peripheral inflammatory mediators, "C-fibers reduction" decreased the paw inflammation. Counter adaptation in C-lesion animals may reduce the modulatory effects of dexamethasone on the remaining C-fibers. Acute dexamethasone diminished the "C-fibers reduction" anti-inflammatory effect, but at chronic treatment, the modulatory effects of dexamethasone aggregated and it augmented the C-fibers reduction anti-inflammatory effect.
ABSTRACT
Different effects of scopolamine on learning, memory, and nitric oxide (NO) metabolites in hippocampal tissues of ovariectomized (OVX) and sham-operated rats were investigated. The animals in the Sham-Scopolamine (Sham-Sco) and OVX-Scopolamine (OVX-Sco) Groups were treated with 2 mg/kg scopolamine before undergoing the Morris water maze, while the animals in the Sham and OVX Groups received saline. The time latency and path length were significantly higher in both the Sham-Sco and the OVX-Sco Groups, in comparison with the Sham and OVX Groups, respectively (p<0.001). Significantly lower NO metabolite levels in the hippocampi of the Sham-Sco Group were observed, compared with the Sham Group (p<0.001), while there was no significant difference between the OVX-Sco and OVX Groups. The decreased NO level in the hippocampus may play a role in the learning and memory deficits induced by scopolamine. However, it seems that the effect of scopolamine on hippocampal NO differs between situations of presence and absence of ovarian hormones.
Diferentes efeitos da escopolamina no aprendizado, na memória e nos níveis dos metabólitos do óxido nítrico (ON) no tecido hipocampal de ratas ovariectomizadas (OVX) e controles com cirurgia sem ooforectomia (Grupo Sham) foram investigados. Os animais dos grupos Sham-Escopolamina (Sham-Sco) e OVX-Escopolamina (OVX-Sco) foram tratados com escopolamina 2 mg/kg antes de entrar no labirinto aquático de Morris, enquanto aqueles dos grupos Sham e OVX receberam solução salina. A latência de tempo e o comprimento do caminho foram significativamente maiores nos Grupos Sham-Sco e OVX-Sco em comparação com os grupos Sham e OVX, respectivamente (p<0,001). Foram observados níveis significativamente mais baixos de metabólitos do ON nos hipocampos do Grupo Sham-Sco em comparação aos níveis do Sham (p<0,001), enquanto não foi observada diferença significativa entre os Grupos OVX-Sco e OVX. A diminuição do nível de ON no hipocampo pode ter um papel no aprendizado e nos déficits de memória induzidos pela escopolamina. No entanto, parece que este efeito da escopolamina no ON hipocampal é diferente em situações de presença ou ausência de hormônios ovarianos.