The Treatment of Keloid Scars via Modulating Heterogeneous Gelatin-Structured Composite Microneedles to Control Transdermal Dual-Drug Release.

Keloid scarring is an abnormal scar disease characterised by excessive proliferation of fibroblasts and over-deposition of collagen during wound healing. Although various treatments for keloid scars have been developed, preventive medicine is believed to be a promising strategy. The skin barrier limits the gentle topical administration of medicaments such as creams and hydrogel dressings, resulting in reduced therapeutic efficacy. In recent years, microneedles (MNs) have been regarded as an appreciable device for topical administration without inducing side effects, and they are painless and do not cause bleeding. In this study, an MN patch with controlled transdermal dual-drug release was developed to achieve combinatory treatment of keloid scars using a heterogeneous gelatin-structured composite MN. Gelatin hydrogel was used as a substrate to load gallic acid (GA) and quercetin-loaded amphiphilic gelatin nanoparticles to fabricate dual-drug heterogeneous composite MNs. The results of the insertion test and mechanical properties of the MNs showed that the heterogeneous composite MN patches could be self-pressed into the stratum corneum and control dual-drug release at different time periods. GA was released at an earlier stage to retard the proliferation of fibroblasts, and quercetin was released at a later stage as a strong antioxidant to erase the generation of reactive oxygen species. Furthermore, real-time quantitative polymerase chain reaction data indicated that the gene expression of fibroblasts (such as Col I and III) was downregulated in the dual-drug system. The above results demonstrate that using heterogeneous composite MNs with the combination of dual-drug pharmacology is beneficial for preventing keloid scar formation.

Functional dilatation and medial remodeling of the renal artery in response to chronic increased blood flow.

BACKGROUND/AIMS: Renal blood flow (RBF) is tightly regulated by several intrinsic pathways in maintaining optimal kidney blood supply. Using a rat model of aortocaval (AC) fistula, we investigated remodeling of the renal artery following prolonged increased blood flow. METHODS: An AC fistula was created in the infrarenal aorta of anesthetized rats, and changes of blood flow in the renal artery were assessed using an ultrasonic flow probe. Morphological changes and expression of endothelial nitric oxide synthase and matrix metalloproteinase-2 in the remodeled renal artery were analyzed. RESULTS: Blood flow in the renal artery increased immediately after creation of AC fistula, but normal RBF was restored 8 weeks later. The renal artery dilated significantly 8 weeks after operation. Expression of endothelial nitric oxide synthase and matrix metalloproteinase-2 was upregulated shortly after blood flow increase, and returned to baseline levels after 3 weeks. Histological sections showed luminal dilatation with medial thickening and endothelial cell-to-smooth muscle cell attachments in the remodeled renal artery. CONCLUSION: Increased RBF was accommodated by functional dilatation and remodeling in the medial layer of the renal artery in order to restore normal blood flow. Our results provide important mechanistic insight into the intrinsic regulation of the renal artery in response to increased RBF.

A Facile Fabrication of Biodegradable and Biocompatible Cross-Linked Gelatin as Screen Printing Substrates.

This study focuses on preparation and valuation of the biodegradable, native, and modified gelatin film as screen-printing substrates. Modified gelatin film was prepared by crosslinking with various crosslinking agents and the electrode array was designed by screen-printing. It was observed that the swelling ratio of C-2, crosslinked with glutaraldehyde and EDC/NHS (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide) was found to be lower (3.98%) than that of C-1 (crosslinked with only glutaraldehyde) (8.77%) and C-0 (without crosslinking) (28.15%). The obtained results indicate that the swelling ratios of both C-1 and C-2 were found to be lower than that of C-0 (control one without crosslinking). The Young's modulus for C-1 and C-2 was found to be 8.55 ± 0.57 and 23.72 ± 2.04 kPa, respectively. Hence, it was conveyed that the mechanical strength of C-2 was found to be two times higher than that of C-l, suggesting that the mechanical strength was enhanced upon dual crosslinking in this study also. The adhesion study indicates that silver ink adhesion on the gelation surface is better than that of carbon ink. In addition, the electrical response of C-2 with a screen-printed electrode (SPE) was found to be the same as the commercial polycarbonate (PC) substrate. The result of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay suggested that the silver SPE on C-2 was non-cytotoxic toward L929 fibroblast cells proliferation. The results indicated that C-2 gelatin is a promising material to act as a screen-printing substrate with excellent biodegradable and biocompatible properties.

Reactive oxygen species mediation of baizhu-induced apoptosis in human leukemia cells.

Baizhu (Atractylodes macrocephala Koidz) has traditionally been used as an important ingredient of several Chinese herbal medicines, which have been used for abdominal pain and gastroenterology diseases for thousands of years. Despite its popularity in herbal therapies, little is known about the anticancer effect of Baizhu. In this study, the anticancer potential of Baizhu on human hepatoma and leukemia cell lines was evaluated. Baizhu methanol extract induced apoptosis in human lymphoma Jurkat T cells, leukemia U937, and HL-60 cells. This was confirmed by several methods, including hypodiploid cells detection using flow cytometry, the examination of apoptotic bodies containing cells using confocal laser scanning microscopy, and hypodiploid cell population inhibition using the broad spectrum caspase inhibitor z-VAD. Finally, the intracellular reactive oxygen species (ROS), especially hydrogen peroxide (H(2)O(2)) and superoxide anion (O(2)(-)), were found to be elevated after treatment of these cells with Baizhu extracts. Antioxidant N-acetyl cysteine (NAC) pretreatment almost completely inhibited Baizhu-induced apoptosis, suggesting that ROS are the key mediators for Baizhu-induced apoptosis. All these data indicate that Baizhu is a possible anti-tumor agent that induces apoptosis of human leukemia cells through ROS generation.

Biphasic effects of chronic intrathecal gabapentin administration on the expression of protein kinase C gamma in the spinal cord of neuropathic pain rats.

OBJECTIVES: Patients suffering from neuropathic pain are difficult to treat and many methods are used to resolve this issue. In this study, we used a model of neuropathic pain comprising rats with chronic constriction injury (CCI) on the left sciatic nerve to investigate the chronic effect of gabapentin via intrathecal administration. We also observed the expression of dorsal spinal protein kinase C gamma subunit (PKCγ) and other pain-related molecules in the spinal area which included cyclooxygenase 2 (COX2), c-Fos and cyclic AMP-dependent transcription factor (ATF3) in the neuropathic pain animals. METHODS: Male Sprague-Dawley (SD) rats (250-380 g) were randomly assigned to four groups, i.e., control, gabapentin (Gaba), MK801, and gabapentin plus MK801 (Gaba+M) groups. A PE-5 catheter was inserted into the lumbar spine area via the cervical spine area. CCI was performed the following day after the intrathecal catheter implant surgery. Gabapentin (1.05 µmol/day) was then given the following day after CCI surgery. Intrathecal gabapentin was administrated for 14 consecutive days. Pain-related behavior was assessed every 2 days thereafter by measuring the latency of foot withdrawal elicited by noxious radiant heat or Von Frey microfilament applied to the hind-paw plantar surface. MK801 (30 µg/day), an N-methyl-D-aspartate (NMDA) receptor blocker, was also added for potential effect. The tissue of dorsal horn of the lumbar spine was harvested on the 14(th) day for the expression of COX2, c-Fos, ATF3 and PKCγ with Western blotting, and positive finding protein was then checked on 7(th) day for further evaluation. RESULTS: The beneficial effect of intrathecal gabapentin of statistic significance on thermal duration and mechanical microfilament appeared after 7-day and 11-day consecutive treatment, respectively. Furthermore, the NMDA receptor blocker also potentiated the effect on the behavior of thermal and mechanical stimulations. Gabapentin had no effect on the expression of COX2, c-Fos and ATF3. Interestingly, the expression of PKCγ in the spinal cord was initially inhibited by gabapentin on the 7(th) day but was potentiated on the 14(th) day. CONCLUSIONS: Our results indicate that chronic intrathecal gabapentin has beneficial effects on the behaviors of both thermal and mechanical stimulations in the neuropathic pain animals and the NMDA blocker can potentiate this effect. Furthermore, gabapentin has biphasic effect on the expression of PKCγ in the spinal cord on Day 7 and Day 14 for the model rats with CCI.

Inhibition of ATP-sensitive potassium channels attenuates propofol-induced vasorelaxation.

BACKGROUND: Infusion of propofol often causes significant vasodilation, which is followed by a profound drop in blood pressure. However, the exact underlying molecular mechanisms of this clinically important phenomenon remain unclear. OBJECTIVE: To determine the biological role of endothelium in propofol-induced vasorelaxation and the underlying molecular mechanisms of this response in the rat aorta. DESIGN, SETTING AND SUBJECTS: Ex vivo assessment of vasomotor function in rat aortic rings, with or without endothelium, after addition of propofol or etomidate. In vivo randomised study of haemodynamic changes in Sprague Dawley rats after administration of propofol, with or without prior infusion of a K(ATP) antagonist. In vitro measurement of intracellular calcium in cultured vascular smooth muscle cells (VSMC) treated with propofol. The experiments were conducted in a research laboratory at the National Cheng Kung University, Taiwan, from August 2008 to July 2009. INTERVENTIONS: Changes in isometric tension of precontracted rat aortic rings were recorded after cumulative addition of propofol (3-300µM). An ATP-sensitive potassium (K(ATP)) channel blocker, glibenclamide (10µM), was incubated in the organ bath before the addition of propofol. Haemodynamic changes after intravenous administration of propofol in the presence or absence of PNU-37883A (a vascular-specific K(ATP) channel blocker) were recorded in anaesthetised rats. Alterations in intracellular calcium and ATP levels in cultured VSMC treated with propofol were measured. RESULTS: Compared with etomidate, propofol induced a significant concentration-dependent vascular relaxation response that was independent of the presence of endothelium. The relaxation response was almost completely abolished by K(ATP) channel antagonism. Levels of intracellular calcium were significantly attenuated in cultured VSMC treated with propofol (10mM). Pre-treatment with PNU- 37883A significantly attenuated propofol-induced hypotension in anaesthetised rats. CONCLUSIONS: Development of hypotension after systemic administration of propofol is mainly caused by its direct relaxation effect on vascular smooth muscle. This response is mainly mediated by activation of K(ATP) channels.