Different regulation type of activation of MMPs has been found in these two diseases. If MMP-2 expression is intense in the mucosa, then this ends with polyp formation; if MMP-7 expression is intense, it ends with CRS or stays as CRS.
In this study, nanocomposite collagen scaffolds incorporating gold nanoparticles (AuNPs) were prepared for wound healing applications. Initially, dose (<20 ppm) and size (>20 nm) of AuNPs that were not cytotoxic on HaCat keratinocytes and 3T3 fibroblasts were determined. Both collagen sponges and AuNP-incorporated nanocomposites (CS-Au) were cross-linked with glutaraldehyde (CS-X and CS-AuX). Incorporation of AuNPs into cross-linked scaffolds enhanced their stability against enzymatic degradation and increased the tensile strength. Hydrolytic degradation of CS-Au group was also less than CS after seven days. Upon confirming in vitro biocompatibility of the scaffolds with cytotoxicity assays, cell attachment and proliferation tests and the in vivo efficacy for healing of full-thickness skin wounds were investigated by applying CS-X, CS-AuX or a commercial product (Matriderm®) onto defect sites and covering with Ioban® drapes. Defects were covered only with drapes for untreated control group. The wound areas were examined with histopathological and biomechanical tests after 14 days of operation. CS-AuX group was superior to untreated control and Matriderm®; it suppressed the inflammation while significantly promoting granulation tissue formation. Inflammatory reaction against CS-AuX was milder than CS-X. Neovascularization was also higher in CS-AuX than other groups, though the result was not significant. Wound closure in CS-X (76%), CS-AuX (69%), and Matriderm® (65%) were better than untreated control (45%). CS-AuX group had the highest tensile strength (significantly higher than Matriderm®) and modulus (significantly higher than Matriderm® and CS-X), indicating a faster course of dermal healing. Further studies are also needed to investigate whether higher loading of AuNPs affects these results positively in a statistically meaningful manner. Overall, their contribution to the enhancement of degradation profiles and mechanical properties, their excellent in vitro biocompatibility, and tendency to accelerate wound healing are encouraging the use of AuNPs in collagen sponges as potent skin substitutes in the future.
Background : In the pathogenesis of urethral stricture, fibrosis is associated with an excessive collagen increase. After the recognition that topical application of Mitomycin-C (MMC) inhibits fibroblast proliferation and is effective in preventing scar formation, many studies have been carried out on this subject outside the scope of urology. The aim of the present study is to observe the intraurethral impact of the employment of low doses of MMC on scar formation and fibrosis in experimental rat model. Methods : Urethral injuries were made by internal urethrotomy knife. The study was carried out with 35 adult male Wistar albino rats. Five rats were allocated to the control group (group 1), 10 to a group that was administered 2 mg/L MMC (group 2) and 20 to a group that was administered 10 mg/ L MMC (group 3). Mitomycin-C was administered to the injured urethra in the form of irrigation for 5 min. The rats were sacrificed 14 days later in order to evaluate chronic inflammation and fibrosis and their penises were histopathologically examined under light microscopy with hematoxilen eosin and trichrom stains. Results : When group 2 was compared with control group, the differences in hemosiderin-laden macrophages (HLM), mononuclear cell infiltration (MCI) and fibrosis were found to be statistically significant (P < 0.01, P < 0.05, P < 0.005, respectively). When group 3 was compared with control group, the differences in HLM, MCI and fibrosis were also found to be statistically significant (P < 0.05, P < 0.05, P < 0.005, respectively). In the comparison of group 2 with group 3, no statistically significant differences were found in terms of the these parameters. Conclusions : Although MMC is toxic at high doses, the antifibrotic effect of the intraurethral low dose MMC may be useful in combination therapy for internal urethrotomy.
Various pharmacological agents have been used to try and elucidate the pathophysiology of ischaemia and necrosis of flaps. Their most important disadvantage is the need for relatively high doses given systemically, which increases the risk of potential side effects. Topical or local agents are more useful. Sildenafil citrate, the specific inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE 5) was studied as an antianginal drug during the late 1980s, but is now used for its effect on erectile function in men. Sildenafil citrate causes dilatation of peripheral arteries and veins and the inhibition of the thrombus-forming ability of platelets in vivo. Our study was designed to test the efficacy of sildenafil citrate on the viability of flaps.
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