Modulation of MCP-1, TGF-ß1, and α-SMA Expressions in Granulation Tissue of Cutaneous Wounds Treated with Local Vitamin B Complex: An Experimental Study.

Vitamin B complex can modulate the inflammatory response and activate wound healing. However, the action mechanisms involved in this process are still unclear. The aim of this study was to evaluate the effects of vitamin B complex on the modulation of monocyte chemotactic protein (MCP)-1, transforming growth factor (TGF)-ß1, and α-smooth muscle actin (α-SMA) in granulation tissue growth. Cutaneous ulcers on Wistar rats were topically treated with vitamin B complex. MCP-1, TGF-ß1, and α-SMA expressions were evaluated 24, 72, and 168 h after the treatment. Inflammatory cells were counted and collagen fibril staining was performed. After 24 h, more mononuclear cells (p ≤ 0.01) and a higher MCP-1 (p ≤ 0.05) and TGF-ß1 (p ≤ 0.01) expression were observed. After 72 h, the number of fibroblasts and mononuclear cells (p ≤ 0.05) was elevated. After 168 h, an increased number of fibroblasts, myofibroblasts, and blood vessels (p ≤ 0.01) as well as a strong intensity of collagen fibril staining were seen. At that point, the cells presented a higher TGF-ß1 expression (p ≤ 0.05), and the size of the ulcer area was decreased (p ≤ 0.01). We can conclude that vitamin B complex may stimulate a positive modulation of MCP-1, TGF-ß1, and α-SMA expressions in granulation tissue of cutaneous ulcers.

Identification of psoralen loaded PLGA microspheres in rat skin by light microscopy.

Drug delivery systems involving the use of polymers are widely studied and discovery of biocompatible polymers has become the focus of research in this area. Psoralen loaded poly(DL-lactide-co-glycolide) (PLGA) microspheres to be used in PUVA therapy (psoralen and UVA irradiation (ultraviolet A, 320-400 nm) of psoriasis were identified in paraffin sections by histological analysis. The psoralen loaded PLGA microspheres were prepared using the solvent evaporation technique. They were spherical and possessed an external smooth surface as observed by scanning electron microscopy (SEM) analysis. This study describes a modification in the routine preparation of microsphere samples for examination by light microscopy. The changes involved fixative agents and/or stains allowing the identification of microspheres containing a non-fluorescent material. The preservation and identification of microspheres in tissues for histological processing in paraffin was greatly improved by these modifications as proven by our results.

Indocyanine green nanoparticles useful for photomedicine.

OBJECTIVE: The aim of this study was to evaluate the potential application of biodegradable nanoparticles (NPs) containing indocyanine green (ICG) in photodynamic therapy (PDT). METHODS: Important parameters, such as particle size and external morphology, were established by dynamic light scattering (DLS) and scanning electron microscopy (SEM). Also, drug encapsulation efficiency and in vitro release behavior were evaluated by spectroscopic methods. RESULTS: The particles are spherical in shape, they exhibit an 817-nm diameter, and they have a low tendency to aggregate. The loading efficiency was 65%. ICG photophysical parameters showed a bathocromic shift in ICG-loaded nanoparticles (ICG-NP). Analysis of the cell P388-D1 in the presence of the ICG-NP by SEM showed that the majority of the nanoparticles were uptaken by phagocytic cells after 2 h of incubation. After laser irradiation photodamage was observed in P388-D1 cells where ICG-NPs had been uptaken by phagocytic cells. CONCLUSION: Polymeric NPs work as an efficient drug delivery system for PDT drugs, and this approach can be used in the administration of amphiphilic photosensitizers in the treatment of neoplasic cells.

Characterization of PLGA microparticles as a drug carrier for 3-ethoxycarbonyl-2h-benzofuro[3,2-f]-1-benzopyran-2-one. Ultrastructural study of cellular uptake and intracellular distribution.

Here we describe the application of microparticles (MPs) for the delivery and release of the drug a benzopsoralen. We also evaluated the intracellular distribution and cellular uptake of the drug by using an encapsulation technique for therapeutic optimization. MPs containing the compound 3-ethoxycarbonyl-2H-benzofuro[3,2-f]-1-benzopyran-2-one (psoralen A) were prepared by the solvent evaporation technique, and parameters such as particle size, drug encapsulation efficiency, effect of the encapsulation process on the drug's photochemistry, zeta potential, external morphology, and in vitro release behavior were evaluated. The intracellular distribution of MPs as well as their uptake by tissues were monitored. Size distribution studies using dynamic ligh scattering and scanning electron microscopy revealed that the MPs are spherical in shape with a diameter of 1.4 micro m. They present low tendency toward aggregation, as confirmed by their zeta potential (+10.6 mV). The loading efficiency obtained was 75%. As a consequence of the extremely low diffusivity of the drug in aqueous medium, the drug release profile of the MPs in saline phosphate buffer (pH 7.4) was much slower than that obtained in the biological environment. Among the population of peritoneal phagocytic cells, only macrophages were able to phagocytose poly-d,l-lactic-co-glycolic acid (PLGA) MP. The use of psoralen A in association with ultraviolet light (360 nm) revealed morphological characteristics of cell damage such as cytoplasmic vesiculation, mitochondria condensation, and swelling of both the granular endoplasmatic reticulum and the nuclear membrane. These results indicate that PLGA MP could be a promising delivery system for psoralen in connection with ultraviolet irradiation therapy (PUVA).

Photobiological and ultrastructural studies of nanoparticles of poly(lactic-co-glycolic acid)-containing bacteriochlorophyll-a as a photosensitizer useful for PDT treatment.

The interaction of polymeric nanoparticles formulated from the biodegradable polymer poly(DL-lactide-co-glycolide) loaded with bacteriochlorophyll-a was studied in homogeneous solution and in vitro in the presence of a macrophage cell line (P388-D1-ATCC). Photodynamic therapy (PDT) activity after different laser doses also was investigated. Scanning electron microscopy analysis of cell phagocyte nanoparticles showed that after 30 min of incubation most of the nanoparticles are in a clear adhesion process to the cell surface. The majority of nanoparticles became phagocytic after 2 hr of incubation time. After laser irradiation of the dye-containing system a total photodamage by nanoparticle phagocyte cells was observed and the cell survival was quantified by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide test. Our results indicate that polymeric nanoparticles work as an efficient drug delivery system for PDT drugs. This approach can be widely used for many other hydrophobic photosensitizers with higher aggregation tendency in neoplastic cell treatment.

Immunolocalization of myosin Va in the developing nervous system of embryonic chicks.

Myosins are molecular motors associated with the actin cytoskeleton that participate in the mechanisms of cellular motility. During the development of the nervous system, migration of nerve cells to specific sites, extension of growth cones, and axonal transport are dramatic manifestations of cellular motility. We demonstrate, via immunoblots, the expression of myosin Va during early stages of embryonic development in chicks, extending from the blastocyst period to the beginning of the fetal period. The expression of myosin Va in specific regions and cellular structures of the nervous system during these early stages was determined by immunocytochemistry using a polyclonal antibody. Whole mounts of chick embryos at 24-30-h stages showed intense immunoreactivity of the neural tube in formation along its full extent. Cross-sections at these stages of development showed strong labeling in neuroepithelial cells at the basal and apical regions of the neural tube wall. Embryos at more advanced periods of development (48 h and 72 h) showed distinctive immunolabeling of neuroepithelial cells, neuroblasts and their cytoplasmic extensions in the mantle layer of the stratified neural tube wall, and neuroblasts and their cytoplasmic extensions in the internal wall of the optic cup, as well as a striking labeling of cells in the apparent nuclei of cranial nerves and budding fibers. These immunolocalization studies indicate temporal and site-specific expression of myosin Va during chick embryo development, suggesting that myosin Va expression is related to recruitment for specific cellular tasks.