Cytotoxicity in ciprofloxacin-treated human fibroblast cells and protection by vitamin E

Antibiotics against Pseudomonas aeruginosa on Human Skin Cell Lines: Determination of the Highest Non-Cytotoxic Concentrations with Antibiofilm Capacity for Wound Healing Strategies

Pseudomonas aeruginosa is one of the most common microorganisms causing infections of severe skin wounds. Antibiotic or antiseptic treatments are crucial to prevent and curb these infections. Antiseptics have been reported to be cytotoxic to skin cells and few studies evaluate the impact of commonly used antibiotics. This study evaluates how clinical antibiotics affect skin cells' viability, proliferation, migration, and cytokine secretion and defines the highest non-cytotoxic concentrations that maintain antibacterial activity. Cell proliferation, viability, and migration were evaluated on cell monolayers. Cytokines related to the wound healing process were determined. The minimum inhibitory concentrations and the impact on bacterial biofilm were assessed. Results showed that 0.02 mg/mL ciprofloxacin and 1 mg/mL meropenem are the highest non-cytotoxic concentrations for fibroblasts and keratinocytes while 1.25 mg/mL amikacin and 0.034 mg/mL colistin do not affect fibroblasts' viability and cytokine secretion but have an impact on keratinocytes. These concentrations are above the minimum inhibitory concentration but only amikacin could eradicate the biofilm. For the other antibiotics, cytotoxic concentrations are needed to eradicate the biofilm. Combinations with colistin at non-cytotoxic concentrations effectively eliminate the biofilm. These results provide information about the concentrations required when administering topical antibiotic treatments on skin lesions, and how these antibiotics affect wound management therapies. This study set the basis for the development of novel antibacterial wound healing strategies such as antibiotic artificial skin substitutes.

Advantageous Combinations of Nanoencapsulated Oregano Oil with Selected Antibiotics for Skin Treatment

The aim of the present study was to evaluate the antimicrobial activity of combinations between encapsulated oregano oil and the most commonly applied antibiotics (ciprofloxacin or gentamicin) against skin infections. In particular, chitosan-alginate nanoparticles loaded with oregano oil and the selected antibiotics were included in methylcellulose hydrogels. Consistency, spreadability, pH of the hydrogel and in vitro release rate of the oil were considered appropriate for topical application. The combination of encapsulated oil and gentamicin in the hydrogel resulted in a synergistic effect against methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) Staphylococcus aureus strains. It was expressed in a fourfold reduction in the effective concentration of gentamicin and 98% inhibition of the bacterial metabolic activity. When ciprofloxacin was included in the combination instead of gentamicin, an additive effect with a two-fold decrease in the effective drug concentration and a 96% reduction in the bacterial metabolic activity were observed. Both combinations significantly inhibited the formation of MRSA biofilm by more than 90% when applied. In vivo application of the hydrogel containing the synergistic combination between the encapsulated oil and gentamicin did not induce irritation of the rabbit skin.

Ionic complexation improves wound healing in deep second-degree burns and reduces in-vitro ciprofloxacin cytotoxicity in fibroblasts

The development of new treatments capable of controlling infections and pain related to burns continues to be a challenge. Antimicrobials are necessary tools, but these can be cytotoxic for regenerating cells. In this study, antibiotic-anesthetic (AA) smart systems obtained by ionic complexation of polyelectrolytes with ciprofloxacin and lidocaine were obtained as films and hydrogels. Ionic complexation with sodium alginate and hyaluronate decreased cytotoxicity of ciprofloxacin above 70% in a primary culture of isolated fibroblasts (p < 0.05). In addition, the relative levels of the proteins involved in cell migration, integrin β1 and p-FAK, increased above 1.5 times (p < 0.05) with no significant differences in cell mobility. Evaluation of the systems in a deep second-degree burn model revealed that reepithelization rate was AA-films = AA-hydrogels > control films > no treated > reference cream (silver sulfadiazine cream). In addition, appendage conservation and complete dermis organization were achieved in AA-films and AA-hydrogels. Encouragingly, both the films and the hydrogels showed a significantly superior performance compared to the reference treatment. This work highlights the great potential of this smart system as an attractive dressing for burns, which surpasses currently available treatments.

Dual acting acid-cleavable self-assembling prodrug from hyaluronic acid and ciprofloxacin: A potential system for simultaneously targeting bacterial infections and cancer

The incidence and of bacterial infections, and resulting mortality, among cancer patients is growing dramatically, worldwide. Several therapeutics have been reported to have dual anticancer and antibacterial activity. However, there is still an urgent need to develop new drug delivery strategies to improve their clinical efficacy. Therefore, this study aimed to develop a novel acid cleavable prodrug (HA-Cip) from ciprofloxacin and hyaluronic acid to simultaneously enhance the anticancer and antibacterial properties of Cip as a superior drug delivery system. HA-Cip was synthesised and characterised (FT-IR, HR-MS, and H1 NMR). HA-Cip generated stable micelles with an average particle size, poly dispersion index (PDI) and zeta potential (ZP) of 237.89 ± 25.74 nm, 0.265 ± 0.013, and -17.82 ± 1.53 mV, respectively. HA-Cip showed ≥80 % cell viability against human embryonic kidney 293 cells (non-cancerous cells), ˂0.3 % haemolysis; and a faster pH-responsive ciprofloxacin release at pH 6.0. HA-Cip showed a 5.4-fold improvement in ciprofloxacin in vitro anticancer activity against hepatocellular cancer (HepG2) cells; and enhanced in vitro antibacterial activity against Escherichia coli and Klebsiella pneumoniae at pH 6.0. Our findings show HA-Cip as a promising prodrug for targeted delivery of ciprofloxacin to efficiently treat bacterial infections associated, and/or co-existing, with cancer.

Hormesis: wound healing and fibroblasts

Hormetic dose responses are reported here to occur commonly in the dermal wound healing process, with the particular focus on cell viability, proliferation, migration and collagen deposition of human and murine fibroblasts with in vitro studies. Hormetic responses were induced by a wide range of substances, including endogenous agents, pharmaceutical preparations, plant-derived extracts including many well-known dietary supplements, as well as physical stressor agents such as low-level laser treatments. Detailed mechanistic studies have identified common signaling pathways and their cross-pathway communications that mediate the hormetic dose responses. These findings complement and extend a similar comprehensive assessment concerning the occurrence of hormetic dose responses in keratinocytes. These findings demonstrate the generality of the hormetic dose response for key wound healing endpoints, suggesting that the hormesis concept has a fundamental role in wound healing, with respect to guiding strategies for experimental evaluation as well as therapeutic applications.

Possible Treatment Approaches of Sulfur Mustard-Induced Lung Disorders, Experimental and Clinical Evidence, an Updated Review

Sulfur mustard (SM) is one of the major potent chemical warfare that caused the death of victims in World War I and the Iraq-Iran conflict (1980-1988). The respiratory system is the main target of SM exposure and there are no definitive therapeutic modalities for SM-induced lung injury. The effects of the new pharmaceutical drugs on lung injury induced by SM exposure were summarized in this review. Literature review on PubMed, ScienceDirect, and Google Scholar databases was performed to find papers that reported new treatment approach on SM-exposure-induced injury in the respiratory system until October 2019. The search was restricted to sulfur mustard AND induced injury (in vitro studies, animal experiments, and clinical trials) AND respiratory system OR lung, AND treatment in all fields. Two hundred and eighty-three relevant articles were identified that 97 retrieved articles were eligible and were included in the review. Some new pharmaceutical drugs have shown therapeutic potential in controlling various characteristics of lung injury due to SM exposure. Recent studies showed therapeutic effects of mucolytic drugs, non-steroidal drugs, and antibiotics on reducing lung inflammation, oxidative stress responses, and modulating of the immune system as well as improving of respiratory symptoms and pulmonary function tests. Studies on the therapeutic effects of new agents with amelioration or treatment of SM-induced lung injury were reviewed and discussed.

Reduction of oxidative stress and ornithine decarboxylase expression in a human prostate cancer cell line PC-3 by a combined treatment with α-tocopherol and naringenin

Differentiation of a human aggressive PC-3 cancer cell line was obtained, in a previous investigation, by the synergic effect of α-tocopherol (α-TOC) and naringenin (NG). This combined treatment induced apoptosis and subsequent reduction of the PC-3 cell proliferation and invasion, by a pro-differentiating action. Since one of the peculiar characteristics of NG and α-TOC is their strong antioxidant activity, this study aimed to investigate their potential effect on the activity of the main enzymes involved in the antioxidant mechanism in prostate cancer cells. NG and α-TOC administered singularly or combined in the PC-3 cell line, affected the activity of several enzymes biomarkers of the cellular antioxidant activity, as well as the concentration of total glutathione (GSH + GSSG) and thiobarbituric acid reactive substances (TBARS). The combined treatment increased the TBARS levels and superoxide dismutase (SOD) activity, while decreased the glutathione S-transferase (GST), glutathione reductase (GR), and glyoxalase I (GI) activities. The results obtained indicate that a combined treatment with these natural compounds mitigated the oxidative stress in the human PC-3 cell line. In addition, a significant reduction of both ornithine decarboxylase (ODC) expression and intracellular levels of polyamines, both well-known positive regulators of cell proliferation, accompanied the reduction of oxidative stress observed in the combined α-TOC and NG treatment. Considering the established role of polyamines in cell differentiation, the synergism with NG makes α-TOC a potential drug for further study on the differentiation therapy in prostate cancer patients.

Effects of low levels of the antibiotic ciprofloxacin on the polychaete Hediste diversicolor: biochemical and behavioural effects

The release of pharmaceutical chemicals in the biosphere can have unpredictable ecological consequences, and knowledge concerning their putative toxic effects is still scarce. One example of a widely used pharmaceutical that is present in the aquatic environment is ciprofloxacin. Previous indications suggest that this drug may exert several adverse effects on exposed biota, but the characterization of a full ecotoxicological response to this drug is far from complete, especially in estuarine ecosystems. This work aimed to characterize the acute and chronic effects of ciprofloxacin in the polychaete Hediste diversicolor (Annelida: Polychaeta), exposed to environmentally relevant levels of this drug, close to the real concentrations of this pharmaceutical in surface waters. The adopted toxic endpoints were behavioral parameters, combined with a biomarker-based approach (quantification of the activities of catalase (CAT), glutathione-S-transferase (GSTs), cholinesterases (ChEs), glutathione peroxidase (GPx), and lipid peroxidation levels. Exposure to ciprofloxacin caused effects on behavioural traits, such as an increase in burrowing times and hyperactivity, alongside alterations in biomarkers, including a significant increase in CAT activity following acute exposure. In addition, and after both acute and chronic exposure, lipid peroxidation was reduced, while AChE activities were enhanced. It was possible to ascertain the occurrence of pro-oxidative alterations following exposure to low levels of ciprofloxacin, which were counteracted by the triggering of CAT activity. The meaning of the enhancement of AChE activity is not clear, but it appears to be linked with the observed behavioural changes, and may have been associated with the stimulation of the behavioural traits. These data strongly suggest that the presence of ciprofloxacin in estuarine areas is not without risks, and exposed biota, namely polychaete species, are likely to have their ecological roles affected, thereby compromising the chemical, physical and microbiological stability of sediments, which in turn alters nutrient cycles.

Antibacterial Anacardic Acid Derivatives

We report on the antibacterial activity of five phenolic lipids derived from anacardic acid characterized by increasing alkyl chain lengths with 6, 8, 10, 12, or 14 carbon atoms. The compounds were profiled for their physicochemical properties, transport across epithelial monolayers, cytotoxicity, and antibacterial activity as compared to common antibiotics. No cytotoxicity was reported in cell lines of fibroblast, hepatic, colorectal, or renal origin. C₁₀ and C₁₂ significantly increased the survival in a Galleria mellonella model infected with multi-drug-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococci (VRE) as compared to the untreated control group. Future studies are required to corroborate these findings in relevant animal model systems of infection.

An Engineered Infected Epidermis Model for In Vitro Study of the Skin's Pro-Inflammatory Response

Wound infection is a major clinical challenge that can significantly delay the healing process, can create pain, and requires prolonged hospital stays. Pre-clinical research to evaluate new drugs normally involves animals. However, ethical concerns, cost, and the challenges associated with interspecies variation remain major obstacles. Tissue engineering enables the development of in vitro human skin models for drug testing. However, existing engineered skin models are representative of healthy human skin and its normal functions. This paper presents a functional infected epidermis model that consists of a multilayer epidermis structure formed at an air-liquid interface on a hydrogel matrix and a three-dimensionally (3D) printed vascular-like network. The function of the engineered epidermis is evaluated by the expression of the terminal differentiation marker, filaggrin, and the barrier function of the epidermis model using the electrical resistance and permeability across the epidermal layer. The results showed that the multilayer structure enhances the electrical resistance by 40% and decreased the drug permeation by 16.9% in the epidermis model compared to the monolayer cell culture on gelatin. We infect the model with Escherichia coli to study the inflammatory response of keratinocytes by measuring the expression level of pro-inflammatory cytokines (interleukin 1 beta and tumor necrosis factor alpha). After 24 h of exposure to Escherichia coli, the level of IL-1β and TNF-α in control samples were 125 ± 78 and 920 ± 187 pg/mL respectively, while in infected samples, they were 1429 ± 101 and 2155.5 ± 279 pg/mL respectively. However, in ciprofloxacin-treated samples the levels of IL-1β and TNF-α without significant difference with respect to the control reached to 246 ± 87 and 1141.5 ± 97 pg/mL respectively. The robust fabrication procedure and functionality of this model suggest that the model has great potential for modeling wound infections and drug testing.

Evaluation of Drug Delivery and Efficacy of Ciprofloxacin-Loaded Povidone Foils and Nanofiber Mats in a Wound-Infection Model Based on Ex Vivo Human Skin

Topical treatment of wound infections is often a challenge due to limited drug availability at the site of infection. Topical drug delivery is an attractive option for reducing systemic side effects, provided that a more selective and sustained local drug delivery is achieved. In this study, a poorly water-soluble antibiotic, ciprofloxacin, was loaded on polyvinylpyrrolidone (PVP)-based foils and nanofiber mats using acetic acid as a solubilizer. Drug delivery kinetics, local toxicity, and antimicrobial activity were tested on an ex vivo wound model based on full-thickness human skin. Wounds of 5 mm in diameter were created on 1.5 × 1.5 cm skin blocks and treated with the investigated materials. While nanofiber mats reached the highest amount of delivered drug after 6 h, foils rapidly achieved a maximum drug concentration and maintained it over 24 h. The treatment had no effect on the overall skin metabolic activity but influenced the wound healing process, as observed using histological analysis. Both delivery systems were efficient in preventing the growth of Pseudomonas aeruginosa biofilms in ex vivo human skin. Interestingly, foils loaded with 500 µg of ciprofloxacin accomplished the complete eradication of biofilm infections with 1 × 10⁹ bacteria/wound. We conclude that antimicrobial-loaded resorbable PVP foils and nanofiber mats are promising delivery systems for the prevention or topical treatment of infected wounds.

Ciprofloxacin-induces free radical production in rat cerebral microsomes

In the presence of ciprofloxacin (CPFX), free radical adduct formation was demonstrated in rat cerebral microsomes using a spin trap α-(4-pyridyl-1-oxide)-N-tert-butyl-nitrone by electron spin resonance spectroscopy. Active microsomes, dihydronicotinamide-adenine dinucleotide phosphate, and ciprofloxacin were necessary for the formation of a spin trap/radical adduct. Adduct formation increased dose-dependently at 0.5-1 mM CPFX concentration for 180 min, and 0.3-1 mM concentration level for 240 min. The addition of SKF 525A, ZnCl₂ or desferrioxamine to the incubation system caused complete inhibition of the radical formation. However, pretreatment of microsomal system with superoxide dismutase (SOD) did not induce any protective effect. Induction of lipid peroxidation, and depletion of thiol levels by CPFX were also shown in the system. These results strongly suggested that CPFX produces free radical(s) in the cerebral microsomes of rats.

Antibacterial Activity of Ciprofloxacin-Encapsulated Cockle Shells Calcium Carbonate (Aragonite) Nanoparticles and Its Biocompatability in Macrophage J774A.1

The use of nanoparticle delivery systems to enhance intracellular penetration of antibiotics and their retention time is becoming popular. The challenge, however, is that the interaction of nanoparticles with biological systems at the cellular level must be established prior to biomedical applications. Ciprofloxacin-cockle shells-derived calcium carbonate (aragonite) nanoparticles (C-CSCCAN) were developed and characterized. Antibacterial activity was determined using a modified disc diffusion protocol on Salmonella Typhimurium (S. Typhimurium). Biocompatibilittes with macrophage were evaluated using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 5-Bromo-2'-deoxyuridine (BrdU) assays. Transcriptional regulation of interleukin 1 beta (IL-1β) was determined using reverse transcriptase-polymerase chain reaction (RT-PCR). C-CSCCAN were spherical in shape, with particle sizes ranging from 11.93 to 22.12 nm. Encapsulation efficiency (EE) and loading content (LC) were 99.5% and 5.9%, respectively, with negative ζ potential. X-ray diffraction patterns revealed strong crystallizations and purity in the formulations. The mean diameter of inhibition zone was 18.6 ± 0.5 mm, which was better than ciprofloxacin alone (11.7 ± 0.9 mm). Study of biocompatability established the cytocompatability of the delivery system without upregulation of IL-1β. The results indicated that ciprofloxacin-nanoparticles enhanced the antibacterial efficacy of the antibiotic, and could act as a suitable delivery system against intracellular infections.

Preparation, degradation and in vitro release of ciprofloxacin-eluting ureteral stents for potential antibacterial application

Drug-eluting stents with biodegradable polymers as reservoirs have shown great potential in the application of interventional therapy due to their capability of local drug delivery. Herein, poly(l-lactide-co-ε-caprolactone) (PLCL) with three different compositions as carriers for ciprofloxacin lactate (CIP) was coated on ureteral stents by the dipping method. To simulate a body environment, degradation behavior of PLCL as both the bulk film and the stent coating was evaluated in artificial urine (AU, pH6.20) respectively at 37°C for 120days by tracing their weight/Mn loss, water absorption and surface morphologies. Furthermore, the release profile of the eluting drug CIP on each stent exhibited a three-stage pattern, which was greatly affected by the degradation behavior of PLCL except for the burst stage. Interestingly, the degradation results on both macroscopic and molecular level indicated that the release mechanism at stage I was mainly controlled by chain scission instead of the weight loss or morphological changes of the coatings. While for stage II, the release profile was dominated by erosion resulting from the hydrolysis reaction autocatalyzed by acidic degradation residues. In addition, ciprofloxacin-loaded coatings displayed a significant bacterial resistance against E. coli and S. aureus without obvious cytotoxicity to Human foreskin fibroblasts (HFFs). Our results suggested that PLCL copolymers with tunable degradation rate as carriers for ciprofloxacin lactate could be used as a promising long-term antibacterial coating for ureteral stents.

Beneficial effects of quercetin on renal injury and oxidative stress caused by ciprofloxacin in rats: A histological and biochemical study

Ciprofloxacin is a broad-spectrum quinolone antibiotic commonly used in clinical practice. Quercetin is an antioxidant belongs to flavonoid group. It inhibits the production of superoxide anion. In this study, we aimed to evaluate the effects of quercetin on renal injury and oxidative stress caused by ciprofloxacin. Twenty-eight female Wistar albino rats were divided into four groups: control, quercetin (20 mg kg(-1) day(-1) gavage for 21 days), ciprofloxacin (20 mg kg(-1) twice a day intraperitoneally for 10 days), and ciprofloxacin + quercetin. Samples were processed for histological and biochemical evaluations. Malondialdehyde (MDA) and glutathione (GSH) levels, superoxide dismutase (SOD), and catalase (CAT) activities were measured in kidney tissue. The ciprofloxacin group showed histopathological changes such as infiltration, dilatation in tubules, tubular atrophy, reduction of Bowman's space, congestion, hemorrhage, and necrosis. In the ciprofloxacin + quercetin group, these histopathological changes markedly reduced. MDA levels increased in the ciprofloxacin group and decreased in the ciptofloxacin + quercetin group. SOD and CAT activities and GSH levels significantly decreased in the ciprofloxacin group. On the other hand, in the ciprofloxacin + quercetin group, SOD and CAT activities and GSH levels significantly increased with regard to the ciprofloxacin group. We concluded that quercetin has antioxidative and therapeutic effects on renal injury and oxidative stress caused by ciprofloxacin in rats.

Increased release time of antibiotics from bone allografts through a novel biodegradable coating

The use of bone allografts is contraindicated in septic revision surgery due to the high risk of graft reinfection. Antibiotic release from the graft may solve the problem and these combinations can theoretically be used for prevention or even therapy of infection. The present study investigated whether amoxicillin, ciprofloxacin, and vancomycin alone or in combination with chitosan or alginate are suitable for short-term or long-term bone coating. Human bone allografts were prepared from femoral head and lyophilized. Antibiotic coating was achieved by incubating the grafts in antibiotic solution and freeze-drying again. Two biopolymers chitosan and alginate were used for creating sustained-release implantable coatings and the drug release profile was characterized in vitro by spectrophotometry. Using lyophilization with or without chitosan only resulted in short-term release that lasted up to 48 hours. Alginate coating enabled a sustained release that lasted for 8 days with amoxicillin, 28 days with ciprofloxacin coating, and 50 days with vancomycin coating. Using only implantable biodegradable allograft and polymers, a sustained release of antibiotics was achieved with ciprofloxacin and vancomycin for several weeks. Since the calculated daily release of the antibiotic was lower than the recommended IV dose, the calcium alginate coated bone graft can support endoprosthesis revision surgery.

Fluoroquinolones and tendinopathy: a guide for athletes and sports clinicians and a systematic review of the literature

CONTEXT

Fluoroquinolone antibiotics have been used for several decades and are effective antimicrobials. Despite their usefulness as antibiotics, a growing body of evidence has accumulated in the peer-reviewed literature that shows fluoroquinolones can cause pathologic lesions in tendon tissue (tendinopathy). These adverse effects can occur within hours of commencing treatment and months after discontinuing the use of these drugs. In some cases, fluoroquinolone usage can lead to complete rupture of the tendon and substantial subsequent disability.

OBJECTIVE

To discuss the cause, pharmacology, symptoms, and epidemiology of fluoroquinolone-associated tendinopathy and to discuss the clinical implications with respect to athletes and their subsequent physiotherapy.

DATA SOURCES

We searched MEDLINE, Cumulative Index to Nursing and Allied Health (CINAHL), Allied and Complementary Medicine Database (AMED), and SPORTDiscus databases for available reports of fluoroquinolone-related tendinopathy (tendinitis, tendon pain, or rupture) published from 1966 to 2012. Search terms were fluoroquinolones or quinolones and tendinopathy, adverse effects, and tendon rupture. Included studies were written in or translated into English. Non-English-language and non-English translations of abstracts from reports were not included (n = 1).

STUDY SELECTION

Eligible studies were any available reports of fluoroquinolone-related tendinopathy (tendinitis, tendon pain, or rupture). Both animal and human histologic studies were included. Any papers not focusing on the tendon-related side effects of fluoroquinolones were excluded (n = 71).

DATA EXTRACTION

Data collected included any cases of fluoroquinolone-related tendinopathy, the particular tendon affected, type of fluoroquinolone, dosage, and concomitant risk factors. Any data outlining the adverse histologic effects of fluoroquinolones also were collected.

DATA SYNTHESIS

A total of 175 papers, including 89 case reports and 8 literature reviews, were identified.

CONCLUSIONS

Fluoroquinolone tendinopathy may not respond well to the current popular eccentric training regimes and may require an alternative, staged treatment approach. Clinicians, athletes, athletic trainers, and their medical support teams should be aware of the need to discuss and possibly discontinue these antibiotics if adverse effects arise.

Embryotoxic and teratogenic effects of norfloxacin in pregnant female albino rats

This study was designed to investigate the possible developmental teratogenicity of norfloxacin in rats. Forty pregnant female rats were divided into four equal groups. Group A received norfloxacin in a dose of 500 mg/kg·b·wt/day orally from 6th to 15th day of gestation. Groups B and C received 1000 and 2000 mg/kg·b·wt/day orally for the same period, respectively; Group D behaved as control and received 0.5 mL distilled water orally for the same period. The dams were killed on 20th day of gestation and their fetuses were subjected to morphological, visceral, and skeletal examinations. Norfloxacin significantly decreased the number of viable fetuses, increased the number of resorbed fetuses, and induced retardation in growth of viable fetuses; some visceral and skeletal defects in these fetuses were seen and these effects were dose dependant. Conclusively, norfloxacin caused some fetal defects and abnormalities, so it is advisable to avoid using this drug during pregnancy.

Protective effect of zinc chloride against cobalt chloride-induced cytotoxicity on vero cells: preliminary results

The aim of this study was to investigate the possible time- and dose-dependent cytotoxic effects of cobalt chloride on Vero cells. The cultured cells were incubated with different concentrations of cobalt chloride ranging from 0.5 to 1,000 μM, and cytotoxicity was determined by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) and resazurin assays. Possible protective effects of vitamin E, coenzyme Q(10), and zinc chloride were also tested in this system. A gradual decrease in cell proliferation was observed at concentrations ~≥ 200 μM in incubation periods of 24, 48, 72, and 96 h with MTT assay. Exposure of cells to 500 and 1,000 μM cobalt chloride caused significant decrease in cell survival. A biphasic survival profile of cells was observed at 1-25 μM concentration range following 96 h of incubation. With resazurin assay, cytotoxicity profile of CoCl(2) was found comparable to the results of MTT assay, particularly at high concentrations and long incubation periods. Dose-dependent cytotoxicity was noted following exposure of cells to ≥ 250 μM of CoCl(2) for 24 h and ≥ 100 μM concentrations of CoCl(2) for 48-96 h. Pretreatment of cells with ZnCl(2) for 4 or 24 h provided significant protection against cobalt chloride-induced cytotoxicity when measured with MTT assay. However, vitamin E or coenzyme Q(10) was not protective. CoCl(2) had dose- and time-dependent cytotoxic effects in Vero cells. Preventive effect of ZnCl(2) against CoCl(2)-induced cytotoxicity should be considered in detail to define exact mechanism of toxicity in Vero cells.

Genotoxic effect of ciprofloxacin during photolytic decomposition monitored by the in vitro micronucleus test (MNvit) in HepG2 cells

PURPOSE

Ciprofloxacin (CIP), a broad-spectrum, second-generation fluoroquinolone, has frequently been found in hospital wastewaters and effluents of sewage treatment plants. CIP is scarcely biodegradable, has toxic effects on microorganisms and is photosensitive. The aim of this study was to assess the genotoxic potential of CIP in human HepG2 liver cells during photolysis.

METHODS

Photolysis of CIP was performed in aqueous solution by irradiation with an Hg lamp, and transformation products were monitored by HPLC-MS/MS and by the determination of dissolved organic carbon (DOC). The cytotoxicity and genotoxicity of CIP and of the irradiated samples were determined after 24 h of exposure using the WST-1 assay and the in vitro micronucleus (MN) test in HepG2 cells.

RESULTS

The concentration of CIP decreased during photolysis, whereas the content of DOC remained unchanged. CIP and its transformation products were not cytotoxic towards HepG2 cells. A concentration-dependent increase of MN frequencies was observed for the parent compound CIP (lowest observed effect level, 1.2 μmol L(-1)). Furthermore, CIP and the irradiated samples were found to be genotoxic with a significant increase relative to the parent compound after 32 min (P < 0.05). A significant reduction of genotoxicity was found after 2 h of irradiation (P < 0.05).

CONCLUSIONS

Photolytic decomposition of aqueous CIP leads to genotoxic transformation products. This proves that irradiated samples of CIP are able to exert heritable genotoxic effects on human liver cells in vitro. Therefore, photolysis as a technique for wastewater treatment needs to be evaluated in detail in further studies, not only for CIP but in general.

Apicoplast-targeting antibacterials inhibit the growth of Babesia parasites

The apicoplast housekeeping machinery, specifically apicoplast DNA replication, transcription, and translation, was targeted by ciprofloxacin, thiostrepton, and rifampin, respectively, in the in vitro cultures of four Babesia species. Furthermore, the in vivo effect of thiostrepton on the growth cycle of Babesia microti in BALB/c mice was evaluated. The drugs caused significant inhibition of growth from an initial parasitemia of 1% for Babesia bovis, with 50% inhibitory concentrations (IC(50)s) of 8.3, 11.5, 12, and 126.6 μM for ciprofloxacin, thiostrepton, rifampin, and clindamycin, respectively. The IC(50)s for the inhibition of Babesia bigemina growth were 15.8 μM for ciprofloxacin, 8.2 μM for thiostrepton, 8.3 μM for rifampin, and 206 μM for clindamycin. The IC(50)s for Babesia caballi were 2.7 μM for ciprofloxacin, 2.7 μM for thiostrepton, 4.7 μM for rifampin, and 4.7 μM for clindamycin. The IC(50)s for the inhibition of Babesia equi growth were 2.5 μM for ciprofloxacin, 6.4 μM for thiostrepton, 4.1 μM for rifampin, and 27.2 μM for clindamycin. Furthermore, an inhibitory effect was revealed for cultures with an initial parasitemia of either 10 or 7% for Babesia bovis or Babesia bigemina, respectively. The three inhibitors caused immediate death of Babesia bovis and Babesia equi. The inhibitory effects of ciprofloxacin, thiostrepton, and rifampin were confirmed by reverse transcription-PCR. Thiostrepton at a dose of 500 mg/kg of body weight resulted in 77.5% inhibition of Babesia microti growth in BALB/c mice. These results implicate the apicoplast as a potential chemotherapeutic target for babesiosis.

Ciprofloxacin-induced antibacterial activity is reversed by vitamin E and vitamin C

In the present study, we investigated the possible involvement of oxidative stress in ciprofloxacin-induced cytotoxicity against several reference bacteria including Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213, and clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA). Oxidative stress was assessed by measurement of hydrogen peroxide generation using a FACScan flow cytometer. The antibacterial activity of ciprofloxacin was assessed using the disk diffusion method and by measuring the minimum inhibitory concentration (MIC). Ciprofloxacin induced a dose-dependent antibacterial activity against all bacteria where the highest tested concentration was 100 ug/ml. Results revealed that E. coli cells were highly sensitive to ciprofloxacin (MIC = 0.21 μg/mL ± 0.087), P. aeruginosa and S. aureus cells were intermediately sensitive (MIC = 5.40 μg/mL ± 0.14; MIC = 3.42 μg/mL ± 0.377, respectively), and MRSA cells were highly resistant (MIC = 16.76 μg/mL ± 2.1). Pretreatment of E. coli cells with either vitamin E or vitamin C has significantly protected cells against ciprofloxacin-induced cytotoxicity. These results indicate the possible antagonistic properties for vitamins C or E when they are used concurrently with ciprofloxacin.

Musculoskeletal complications of fluoroquinolones: guidelines and precautions for usage in the athletic population

Fluoroquinolone antibiotics are associated with a wide spectrum of musculoskeletal complications that involve not only tendon but also cartilage, bone, and muscle. Insights into the pathoetiology of fluoroquinolone toxicity on musculoskeletal tissues have been evolving over recent years. Although the pathoetiology is certainly multifactorial, alterations in cell signaling proteins and direct toxic effects on musculoskeletal tissues have been strongly implicated. Increasing age and concomitant systemic corticosteroid use appear to significantly increase the risk of adverse events. The purpose of this article is to review the musculoskeletal complications associated with use of fluoroquinolone antibiotics by adults; identify risk factors associated with fluoroquinolone toxicity; explore the possible pathoetiology of fluoroquinolone toxicity on tendon, cartilage, bone, and muscle; and offer recommendations regarding evaluation and treatment of fluoroquinolone-associated musculoskeletal complications. In addition, this review will provide recommendations regarding fluoroquinolone use in athletes and return to play after fluoroquinolone exposure.

Time- and concentration-dependent cytotoxicity of antibiotics used in endodontic therapy

OBJECTIVE

New drugs have to be assessed in endodontic therapy due to the presence of microorganisms resistant to therapeutic procedures. Thus, this study evaluated the time- and concentration-dependent cytotoxicity of different antibiotics used in endodontic therapy.

MATERIAL AND METHODS

Human gingival fibroblasts were treated and divided into the following experimental groups: Group I - control; Group II - ciprofloxacin hydrochloride; Group III - clyndamicin hydrochloride; and Group IV - metronidazole. Each drug was used at concentrations of 5, 50, 150, and 300 mg/L for 24, 48, 72, and 96 h. Cytotoxicity was evaluated by the MTT assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] and spectrophotometric reading of ELISA plates. The results were analyzed by BioEstat 4.0 software using Kruskal-Wallis and Dunn's tests at a significance level of 5%. Cell viability was assessed for the different concentrations and times.

RESULTS

All drugs presented dose-dependent cytotoxicity. Concentrations of 5 and 50 mg/L produced viable fibroblasts at all experimental times in all groups.

CONCLUSIONS

Cell viability at 24 h was greater than in the other experimental times. Comparison between the same concentrations of antibiotics at different times showed that metronidazole presented the highest cell viability at 72 and 96 h compared to the other antibiotics, whereas clyndamicin hydrochloride showed higher cell viability at 72 h than ciprofloxacin hydrochloride.

Does ciprofloxacin have an obverse and a reverse?

Ciprofloxacin is an antibiotic that belongs to fluoroquinoles, characterized by broad spectrum of action against pathogens, especially Gram(-) aerobic bacilli. For a long time, it has been thought that ciprofloxacin has an effect only on bacterial cells. Now it is known, that this drug can significantly affect eukaryotic cells including human cancer cells. Its bactericidal action relay on inhibition of topoisomerase II, enzyme responsible for alterations in 3D structure of DNA during replication, transcription and chromatin condensation. Thanks to that, ciprofloxacin can induce cell cycle arrest and apoptosis of cancer cells. The effectiveness of ciprofloxacin was confirmed in several in vitro studies on tumor cell lines such as: human bladder cells, leukaemic cell lines, human osteosarcoma cells, human prostate cancer cells, human colorectal carcinoma cells and human non-small cell lung cancer cell line. Ciprofloxacin is particularly effective against non-small cell lung cancer mainly due to accumulation of ciprofloxacin in lung tissue after intravenous administration and its toxicity against lung cancer lines in vitro in a concentration and time-dependent manner.

Fluoroquinolones lower constitutive H2AX and ATM phosphorylation in TK6 lymphoblastoid cells via modulation of the intracellular redox status

Accumulation of reactive oxygen species (ROS)-induced damage and mutations in the genomic DNA is considered the primary etiology of aging and age-related pathologies including cancer. Strategies aimed at slowing these conditions often involve protecting against oxidative DNA damage via modulation of the intracellular redox state. Recently, a biomarker of DNA double-strand breaks (DSBs), serine 139-phosphorylated histone H2AX (gammaH2AX), and its upstream mediator, activated PI-3-related kinase, ATM (ATM(P1981)), were shown to be constitutively expressed in cells and modulated by antioxidant treatment. Thus, both constitutive histone H2AX phosphorylation (CHP) and constitutive ATM activation (CAA) are thought to reflect a cell's response to endogenous ROS-induced DSBs. In the present study, we investigated the effects of a battery of fluoroquinolone (FQ) compounds, namely ciprofloxacin, enrofloxacin, gatifloxacin, lomefloxacin and ofloxacin, on CHP and CAA in human TK6 lymphoblastoid cells. All FQs tested reduced CHP and CAA compared to controls following 6 and 24 h treatment with CAA being more sensitive to their effects at both time points. In addition, intracellular ROS levels and mitochondrial activities were also lowered in FQ-treated cells at 6 and 24 h.We presume that FQs mediate this effect via a combination of ROS-scavenging and mitochondrial suppression and therefore may protect against the onset or may slow the progression of numerous oxidative pathophysiological conditions.

A rare case of ciprofloxacin-induced bilateral rupture of the Achilles tendon

Fluoroquinolone antibiotics have been widely used for over 25 years. Their key adverse effect is tendinopathy. A 76-year-old woman developed bilateral Achilles tendinopathy on the fourth day of fluoroquinolone use. Her doctor advised her to complete the course; however, she went on to sustain bilateral tendoachilles rupture. The patient undertook self-referral to a Primary Care Musculoskeletal Assessment Service, where bilateral Achilles tendon rupture was confirmed by ultrasonography. Surgical repair of both tendons was undertaken. Several months postoperatively the patient was discharged. Fluoroquinolone-related tendinopathy can occur within hours of commencing the medication or up to 6 months post cessation. The incidence of Achilles tendon disorders significantly outweighs pathology in other tendons. Men are up to four times more susceptible than women, hence bilateral rupture in a 76-year-old woman is rare. Patients prescribed fluoroquinolones presenting with tendinopathy require consideration of dose reduction or cessation of fluoroquinolone therapy.

The mitochondria targeted antioxidant MitoQ protects against fluoroquinolone-induced oxidative stress and mitochondrial membrane damage in human Achilles tendon cells

Tendinitis and tendon rupture during treatment with fluoroquinolone antibiotics is thought to be mediated via oxidative stress. This study investigated whether ciprofloxacin and moxifloxacin cause oxidative stress and mitochondrial damage in cultured normal human Achilles' tendon cells and whether an antioxidant targeted to mitochondria (MitoQ) would protect against such damage better than a non-mitochondria targeted antioxidant. Human tendon cells from normal Achilles' tendons were exposed to 0-0.3 mM antibiotic for 24 h and 7 days in the presence of 1 microM MitoQ or an untargeted form, idebenone. Both moxifloxacin and ciprofloxacin resulted in up to a 3-fold increase in the rate of oxidation of dichlorodihydrofluorescein, a marker of general oxidative stress in tenocytes (p<0.0001) and loss of mitochondrial membrane permeability (p<0.001). In cells treated with MitoQ the oxidative stress was less and mitochondrial membrane potential was maintained. Mitochondrial damage to tenocytes during fluoroquinolone treatment may be involved in tendinitis and tendon rupture.

Hormesis [biological effects of low level exposures (BELLE)] and dermatology

Hormesis, or biological effects of low level exposures (BELLE), is characterized by nonmonotonic dose response which is biphasic, displaying opposite effects at low and high dose. Its occurrence has been documented across a broad range of biological models and diverse type of exposure. Since hormesis appears to be a relatively common phenomenon in many areas, the objective of this review is to explore its occurrence related to dermatology and its public health and risk assessment implication. Hormesis appears to be a common phenomenon in in-vitro skin biology. However, in vivo data are lacking and the clinical relevance of hormesis has yet to be determined. Better understanding of this phenomenon will likely lead to different strategies for risk assessment process employed in the fields of dermatologic toxicology and pharmacology. We believe that hormesis is a common phenomenon and should be given detailed consideration to its concept and its risk assessment implications, and how these may be incorporated into the experimental and regulatory processes in dermatology. The skin, with its unique characteristics, its accessibility, and the availability of non-invasive bioengineering and DNA microarray technology, will be a good candidate to extend the biology of hormesis.

Diminished ciprofloxacin-induced chondrotoxicity by supplementation with magnesium and vitamin E in immature rats

Quinolone-induced chondrotoxicity in juvenile rats and multiple other species has been demonstrated previously. Identical damages can be induced in immature rats by feeding them a magnesium-deficient diet. The objective of the present study was to investigate whether, in reverse, oral supplementation with magnesium, vitamin E, or both can diminish the typical quinolone-induced arthropathy in juvenile Wistar rats. Four groups of 12 (6 male, 6 female) 24-day-old Wistar rats were each fed either normal feed (group A), a vitamin E-enriched diet (group B), a magnesium-enriched diet (group C), or a diet enriched with both vitamin E and magnesium (group D) for 10 days. All rats received two subcutaneous ciprofloxacin doses of 600 mg/kg of body weight on postnatal day 32. Two days later, the rats were sacrificed and cartilage samples from knee joints were examined under a light microscope for the presence of typical quinolone-induced joint cartilage lesions. In addition, magnesium, calcium, and vitamin E concentrations in cartilage and plasma were determined. In the samples from rats fed a normal diet (group A), 17 quinolone-induced joint cartilage lesions were observed. In groups fed an enriched diet, the incidence of specific lesions (n) was significantly lower: group B, n = 10 (41% reduction compared to the incidence for group A; P < 0.05); group C, n = 6 (65% reduction; P < 0.01); and group D, n = 3 (82% reduction; P < 0.01). In comparison to the standard diet, diets with magnesium and vitamin E supplementation resulted in significantly higher magnesium and vitamin E concentrations in plasma and articular cartilage. Supplementation with magnesium and vitamin E alone or in combination may relevantly diminish joint cartilage lesions induced by quinolones in immature rats, with an additive effect of combined supplementation. The data further support the proposed pathomechanism of quinolone-induced arthropathy and the crucial role of magnesium in immature joint cartilage.

Cytotoxic effect of ciprofloxacin in primary culture of rat astrocytes and protection by Vitamin E

The aim of this study was to investigate the possible cytotoxic and oxidative stress inducing effects of ciprofloxacin (CPFX) on primary cultures of rat astrocytes. The cultured cells were incubated with various concentrations of CPFX (0.5-300mg/l), and cytotoxicity was determined by neutral red (NR) and MTT assays. Survival profile of cells was biphasic in NR assay: CPFX did not cause any alteration at any concentration for 7h, whereas < or =50mg/l concentrations induced significant cell proliferation in incubation periods of 24, 48, 72, and 96h. However, cell proliferation gradually decreased at higher concentrations, and 200 and 300mg/l of CPFX exposure was found to be significantly (p<0.05) cytotoxic at all time periods. With MTT assay, no alteration was noted for incubation period of 7h, as observed with NR assay. But, cell viability decreased with approximately > or =50mg/l CPFX exposure in all other time periods. Cell proliferation was only seen in 24h of incubation with 0.5 and 5mg/l CPFX. Vitamin E pretreatment of cell cultures were found to be providing complete protection against cytotoxicity of 300mg/l CPFX in 96h incubation when measured with both NR and MTT assays. The SOD pretreatment was partially protective with NR assay, but no protection was noted when measured with MTT. A significant enhancement of lipid peroxidation was observed with the cytotoxic concentration of the drug, but total glutathione content and catalase activity of cells did not change. The data obtained in this study suggest that, in accordance with our previous results with fibroblast cells, CPFX-induced cytotoxicity is related to oxidative stress. And the biphasic effect of CPFX possibly resulted from the complex dose-dependent relationships between reactive oxygen species, cell proliferation, and cell viability.

Glyphosate-induced antioxidant imbalance in HaCaT: The protective effect of Vitamins C and E

Roundup 3 plus(®), a glyphosate-based herbicide, is widely used in the ground, but its extensive use has posed a health risk in man. The aim of this study was firstly to investigate how glyphosate alone or included in Roundup 3 plus(®) affected the antioxidant defense system and lipid peroxidation of human cutaneous cells, and secondly, to evaluate the ameliorating effects of antioxidants, as Vitamin C (VitC) and Vitamin E (VitE), against Roundup 3 plus(®)-induced epidermal antioxidant impairment. Our results showed that glyphosate alone or included in Roundup 3 plus(®), induced significant changes in cellular antioxidant status as a glutathione depletion, enzymatic (catalase, glutathione-peroxidase and superoxide dismutase) disorders, and increased lipid peroxidation. VitC or VitE supplementation increased superoxide dismutase, glutathione-reductase and -peroxidase activities and reduced lipid peroxidation in Roundup 3 plus(®)-treated keratinocytes. These in vitro data indicated that VitC and VitE might have preventive effects against deleterious cutaneous cell damage caused by Roundup 3 plus(®).

Ciprofloxacin‐Induced Glutathione Redox Status Alterations in Rat Tissues

The possible oxidative stress inducing effect of a fluoroquinolone (FQ) antibiotic, ciprofloxacin (CPFX), was investigated in rats measuring glutathione redox status. For this purpose, the drug was administered to rats as two different single doses (100 and 150 mg/kg, ip) or a repeated dose (500 mg/kg/d, ig, for 5d). Then, total and oxidized glutathione levels were determined in hepatic and cerebral tissues of the rats by an enzymatic cycling assay, and the glutathione redox status was calculated. The possible protective effects of vitamin E or allopurinol against CPFX-induced alterations on glutathione system have also been examined. Following both routes of administration of CPFX, the total glutathione content of the liver, but not of brain decreased significantly. The oxidized glutathione (GSSG) in the brain increased after single or repeated dose treatments, but only with repeated doses of CPFX in the liver. CPFX induced dose-dependent alterations in the glutathione redox status in both tissues. With single doses the effect was more pronounced in cerebral tissue, and with repeated ig doses it was significant in both tissues. Pretreatment of rats with vitamin E or allopurinol before the administration of CPFX provided marked protection against glutathione redox status alterations in both tissues. Our results, thus, indicate that CPFX treatment introduces an oxidative stress in cerebral and hepatic tissues of rat.

Biphasic response of ciprofloxacin in human fibroblast cell cultures

To investigate the possibility of the involvement of an oxidative stress induction in the mechanism of the cytotoxic effect of quinolone antibiotics, we examined the viability of human fibroblast cells exposed to ciprofloxacin (CPFX), and measured the levels of lipid peroxidation (LP), glutathione (GSH), and the activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX). The data showed that the effect of CPFX on the viability of cells, as determined by neutral red uptake assay, was time-dependent, and the dose-response relation was biphasic. Cytotoxicity was not observed in the concentration range 5-150 mg/l CPFX when the cells were incubated for 24 h. In contrast, lower concentrations (5 and 12.5 mg/l) of CPFX increased the cell growth in all incubation periods tested. Marked decreases in the viability of fibroblasts were observed at concentrations 50 and 75 mg/l, and >/=50 mg/l, following 48 and 72 h exposure, respectively (p < 0.05). However, when the cells were exposed to > 75 mg/l CPFX for 48 h, no cytotoxicity was observed. By exposing fibroblast cultures to 75 mg/l CPFX for 48 h, an induction of LP enhancement and a marked decrease in intracellular GSH were observed. Vitamin E pretreatment of the cells lowered the level of LP, increased the total GSH content, and provided significant protection against CPFX-induced cytotoxicity. The biphasic effect of CPFX possibly resulted from the complex dose-dependent relationships between reactive oxygen species (ROS), cell proliferation, and cell viability. It was previously reported, in fact, for several cell models that ROS exert a biphasic effect on cell growth. Furthermore, cultured fibroblasts release their own free radicals, and the inhibition of endogenous ROS inhibits the fibroblast cell proliferation, whereas the effect of exogenous ROS is biphasic.