RESUMO
Surfactin is a typical kind of biosurfactant with a large diversity of structure, and its molecular structure is expected to play a crucial role in its adsorption dynamics. Adsorption kinetics of surfactin homologues at the n-hexadecane/aqueous solution interface is studied using a droplet-based microfluidic method. Molecular dynamics simulations are performed to illustrate the dependence of adsorption energy on the surfactin structure. Rapid reduction of dynamic interfacial tensions is obtained. The best fit to experimental results reveals that surfactin with shorter aliphatic chains, C13-surfactin and C14-surfactin, has larger rate constants of adsorption and desorption. Interfacial tensions are rapidly reduced in the case of the oil/water interface which is freshly formed, and the equilibrium adsorption is rapidly established approximately in 100-350 ms at concentrations above the critical micelle concentration. C15-surfactin that has a longer aliphatic chain adsorbs and desorbs slower, and the equilibration time of adsorption is slightly longer. Moreover, C15-surfactin has a strong tendency for adsorbing at the interface, which is in accordance with the larger adsorption energy obtained by molecular dynamics simulation, and aggregating behavior in solution. The present study provides insights on the surfactin structure and the dynamics of adsorption at the liquid/liquid interface.
RESUMO
It is well known that bone marrow stromal cells (BMSC) grafted into the hippocampus of the rat model of Alzheimer's disease (AD) could survive and differentiate into cholinergic neurons as well as contribute towards functional restoration. The present study evaluated the effects of BMSC as a seed cell modified by nerve growth factor (NGF) gene into the hippocampus of AD rats. The beta-amyloid protein was injected bilaterally into the rat hippocampus to reproduce the AD model. After the human total RNA was extracted, the NGF gene was amplified by reverse transcription-polymerase chain reaction, then cloned into the pcDNA3. BMSC derived from a green fluorescence protein transgenic mouse were isolated, cultured, identified, and transfected by the NGF recombinant. The NGF-gene-modified BMSC were then transplanted into the hippocampus of AD rats. The results showed that implanted BMSC survived, migrated and expressed NGF as well as differentiated into ChAT-positive neurons. A significant improvement in learning and memory in AD rats was also seen in NGF-gene-modified BMSC group, when compared with the BMSC group. The present findings suggested that BMSC provided an effective carrier for delivery of NGF into AD rats, and the administration of NGF-gene-modified BMSC may be considered as a potential strategy for the development of effective therapies for the treatment of AD.
Assuntos
Doença de Alzheimer , Células da Medula Óssea/fisiologia , Fator de Crescimento Neural/genética , Transplante de Células-Tronco , Células Estromais/fisiologia , Animais , Comportamento Animal/fisiologia , Células da Medula Óssea/citologia , Diferenciação Celular , Sobrevivência Celular , Modelos Animais de Doenças , Feminino , Hipocampo/citologia , Humanos , Camundongos , Fator de Crescimento Neural/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Células Estromais/citologiaRESUMO
This study investigated the effects of bone marrow stromal cells transplantation on Alzheimer's disease (AD). Bone marrow stromal cells (BMSC) were obtained from the bone marrow of transgenic mice expressing green fluorescent protein and transplanted into the hippocampus of rats, which had received an injection of beta amyloid protein into the hippocampus 8 days earlier. Morris Water Maze test was used to observe behavior 2 weeks after transplantation. The survival and differentiation of the grafts were studied immunohistochemically. Behavior improved significantly in the transplanted group. The transplanted BMSC survived and presented ChAT-like neurons, indicating that these transplanted cells might differentiate into cholinergic neurons and the procedure could be a promising therapy for Alzheimer's disease.
Assuntos
Doença de Alzheimer/terapia , Transplante de Medula Óssea/métodos , Transtornos Cognitivos/terapia , Hipocampo/metabolismo , Células Estromais/fisiologia , Células Estromais/transplante , Acetilcolina/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/fisiopatologia , Peptídeos beta-Amiloides/efeitos adversos , Animais , Animais Geneticamente Modificados , Biomarcadores/metabolismo , Diferenciação Celular/fisiologia , Colina O-Acetiltransferase/metabolismo , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/fisiopatologia , Modelos Animais de Doenças , Feminino , Sobrevivência de Enxerto/fisiologia , Proteínas de Fluorescência Verde , Hipocampo/citologia , Hipocampo/cirurgia , Imuno-Histoquímica , Masculino , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Ratos , Ratos Sprague-Dawley , Resultado do TratamentoRESUMO
This study evaluated the therapeutic effect of neural stem cells (NSCs) transplanted into Parkinson's disease (PD) rats. NSCs were identified in vitro, then engrafted into the striatum of the PD rats. The rotational behavior was evaluated 1, 2, 4 and 6 weeks. A significant rotational behavior improvement was observed in PD rats subjected to cell transplantation. Transplanted NSCs not only express Nerve growth factor and Neurotrophin-3 in vitro, but also survive and partly differentiate into tyrosine hydroxylase (TH) positive cells in vivo. The results show that NSCs could be effective for PD treatment and the mechanisms might involve the neurotrophin expression and the neural differentiation.
