ABSTRACT
BACKGROUND: Photodynamic antimicrobial chemotherapy holds broad-spectrum antibacterial ability, fast onset of action and non-resistance, which has been extensively applied in the treatment of superficial localized infection. OBJECTIVE: To explore the efficacy of photodynamic antimicrobial chemotherapy for treating osteomyelitis. METHODS: Thirty-six New Zealand white rabbits (provided by Laboratory Animal Center of Academy of Military Medical Sciences) were selected, and a left tibia osteomyelitis model was established. At 28 days after modeling, rabbit models were randomly divided into three groups: Blank group (tibia debridement only), control group (vancomycin/polymethylmethacrylate bone cement was filled into the intramedullary cavity of the infectious tibia after debridement), and experimental group (intramedullary treatment of photodynamic antimicrobial chemotherapy after debridement). The gross observation, imaging examination and bacterial culture were performed at 4, 8, and 12 weeks after surgery. The study was approved by the Ethical Committee of Affiliated Hospital of Logistics College of CAPF, with the approval No. (2015)-0002. RESULTS AND CONCLUSION: (1) Appearance of the skin: Purulent secretion was observed in the blank group, but disappeared in the control and experimental groups where the skin healed well. (2) X-ray examination: With time going, the osteomyelitis aggravated in the blank group. The bone destruction was reduced gradually in the control and experimental groups, and the bone defects healed gradually. There was no significant difference between control and experimental groups at different time points after surgery. (3) Bacterial culture: With time increasing, the bacterial positive rate showed no significant change in the blank group. The bacterial positive rate in the control and experimental groups was on a decline, which showed no significant difference between control and experimental groups at different time points after surgery (P > 0.05). (4) These results indicate that photodynamic antimicrobial chemotherapy is a new treatment for osteomyelitis to effectively control infection, providing experimental basis in clinical practice.
ABSTRACT
Objective To investigate susceptibility and antibacterial activity of cationic porphyfin derivative mediated photodynamic antimicrobial chemotherapy (CPD-PACT) against Pseudomonas aeruginosa,to provide experimental evidence for its high efficiency antibacterial activity.Methods The impacts of culture environments on minimum inhibitory concentration (MIC) were measured by double dilution method.The formation of inhibition zone was determined by diffusion plate method.The postantibiotic effect was analyzed by colony forming units.The viability and morphology of Pseudomonas aeruginosa were observed by confocal laser scanning microscopy (CLSM).Results The inoculum size of bacterial had a certain effect on the MIC.The MIC values increased as the pH of medium rose.When the calf serum content of culture medium increased,the MIC rose in light reaction and dropped in dark reaction.The diameter of inhibition zone mainly depended on the laser energy density,but not the concentration of photosensitizer.Though CPD possessed strong antimicrobial activity and persistent suppression on bacterial growth,the surviving Pseudomonas aeruginosa would soon continue to proliferate after PACT.The fluorescence images captured by CLSM showed that CPD-PACT could destroy the membrane integrity,leak the cytoplasmic component,decrease the bacterial activity and finally lead Pseudomonas aeruginosa to death.Conclusions CPD has strong inhibitory activity and obvious postantibiotic effect on Pseudomonas aeruginosa,which is suitable to be developed as an drug candidate for PACT.
ABSTRACT
Este estudo teve por objetivos (1) estudar os efeitos de diferentes parâmetros de terapia fotodinâmica sobre a viabilidade de células planctônicas e biofilme de S. mutans UA159, (2) verificar a viabilidade de uso de um modelo para crescimento de biofilme bacteriano no estudo do processo de desmineralização, (3) avaliar a capacidade da terapia fotodinâmica em controlar o processo de desmineralização mediado por biofilme de S. mutans crescidos sobre discos de dentina bovina e (4) mensurar a capacidade da terapia fotodinâmica em promover estresse celular a S. mutans UA159 com deleção do gene VicK. Os procedimentos de terapia fotodinâmica foram realizados pela associação do fotossensibilizador Photogem® e de um LED vermelho visível (Biotable®, 630 nm, 50 mW/cm2) como fonte de luz. A viabilidade de células bacterianas foi determinada por dois métodos distintos: teste de atividade metabólica pelo uso da resazurina (etapa 1) e contagem de UFC (etapas 1,2 e 3). Microrradiografia transversal e análise da concentração de cálcio por espectrometria de absorção atômica foram os métodos de escolha para a determinação do perfil do conteúdo mineral (%vol), perda mineral integrada (PMI, %vol x m), profundidade de lesão (PL, m) e concentração de cálcio liberado em meio de cultura (mg/dL). A intensidade de fluorescência emitida pela modulação da proteína GFP após ensaio de estresse celular foi determinada por citometria de fluxo. Os diferentes parâmetros de terapia fotodinâmica foram capazes de reduzir a viabilidade de células planctônicas de S. mutans, bem como das células organizadas em biofilme (ANOVA a um critério, Games-Howell, p<0,05), sendo o resultado dose-dependente. Quando Photogem® a 0,25 mg/mL foi associado ao LED a 150 J/cm2, uma redução de aproximadamente 3,9 log10 na contagem de células viáveis provenientes de biofilme foi observada. O modelo para crescimento de biofilme permitu a progressão do processo de...
The present study aimed (1) to assess the effects of different parameters of Photodynamic Antimicrobial Chemotherapy (PACT) on the viability of planktonic cells and biofilm of S. mutans UA159, (2) to test the effectiveness of a biofilm model in evaluating the demineralization process, (3) to assess the influence of PACT on the control of demineralization process mediated by S. mutans biofilm growth on dentin discs, and (4) to measure the ability of PACT in promoting cellular stress on S. mutans UA159 knockout vicK gene. PACT procedures were performed by association between a photosensitizer (Photogem®) and a visible red LED (Biotable®, 630 nm, 50 mW/cm2) as light source. Viability of bacterial cells was determined by two distinct methods: resazurin assay (phase 1) and Colony Forming Unit (CFU) counts (phases 1, 2, and 3). Transversal microradiography and calcium release analysis by atomic absorption spectrometry were chosen to analyze mineral content profile (%vol), integrated mineral loss (IML, %vol x m), lesion depth (LD, m), and concentration of calcium release in culture media (mg/dL). Fluorescence intensity levels, which were modulated by expression of Green Fluorescent Protein-reporter (GFP) after cellular stress, were measured by flow cytometer. A dose-dependent effect on the reduction of viability of planktonic cells and biofilm of S. mutans was observed after application of different parameters of PACT (one-way ANOVA, Games-Howell, p<0.05). 0.25 mg/mL Photogem® plus 150 J/cm2 LED decreased in nearly 3.9 log10 the viability of S. mutans biofilm. Progression of demineralization process was correlated with the time (24 h IML: 1905±391 vol% x m, LD: 69.9±12,2 m; 48 h - IML: 3529±886 vol% x m, LD: 114.2±24.6 m; 72 h - IML: 4186±1099 vol% x m, LD: 146.1±20.1 m). Integrated mineral loss, lesion depth and concentration of calcium release...
Subject(s)
Animals , Cattle , Biofilms/growth & development , Tooth Demineralization/drug therapy , Photochemotherapy , Streptococcus mutans/growth & development , Streptococcus mutans/radiation effects , Analysis of Variance , Colony Count, Microbial , Culture Media , Dental Caries/prevention & control , Dentin/microbiology , In Vitro Techniques , Time FactorsABSTRACT
Este estudo teve por objetivos (1) estudar os efeitos de diferentes parâmetros de terapia fotodinâmica sobre a viabilidade de células planctônicas e biofilme de S. mutans UA159, (2) verificar a viabilidade de uso de um modelo para crescimento de biofilme bacteriano no estudo do processo de desmineralização, (3) avaliar a capacidade da terapia fotodinâmica em controlar o processo de desmineralização mediado por biofilme de S. mutans crescidos sobre discos de dentina bovina e (4) mensurar a capacidade da terapia fotodinâmica em promover estresse celular a S. mutans UA159 com deleção do gene VicK. Os procedimentos de terapia fotodinâmica foram realizados pela associação do fotossensibilizador Photogem® e de um LED vermelho visível (Biotable®, 630 nm, 50 mW/cm2) como fonte de luz. A viabilidade de células bacterianas foi determinada por dois métodos distintos: teste de atividade metabólica pelo uso da resazurina (etapa 1) e contagem de UFC (etapas 1,2 e 3). Microrradiografia transversal e análise da concentração de cálcio por espectrometria de absorção atômica foram os métodos de escolha para a determinação do perfil do conteúdo mineral (%vol), perda mineral integrada (PMI, %vol x m), profundidade de lesão (PL, m) e concentração de cálcio liberado em meio de cultura (mg/dL). A intensidade de fluorescência emitida pela modulação da proteína GFP após ensaio de estresse celular foi determinada por citometria de fluxo. Os diferentes parâmetros de terapia fotodinâmica foram capazes de reduzir a viabilidade de células planctônicas de S. mutans, bem como das células organizadas em biofilme (ANOVA a um critério, Games-Howell, p<0,05), sendo o resultado dose-dependente. Quando Photogem® a 0,25 mg/mL foi associado ao LED a 150 J/cm2, uma redução de aproximadamente 3,9 log10 na contagem de células viáveis provenientes de biofilme foi observada. O modelo para crescimento de biofilme permitu a progressão do processo de...
The present study aimed (1) to assess the effects of different parameters of Photodynamic Antimicrobial Chemotherapy (PACT) on the viability of planktonic cells and biofilm of S. mutans UA159, (2) to test the effectiveness of a biofilm model in evaluating the demineralization process, (3) to assess the influence of PACT on the control of demineralization process mediated by S. mutans biofilm growth on dentin discs, and (4) to measure the ability of PACT in promoting cellular stress on S. mutans UA159 knockout vicK gene. PACT procedures were performed by association between a photosensitizer (Photogem®) and a visible red LED (Biotable®, 630 nm, 50 mW/cm2) as light source. Viability of bacterial cells was determined by two distinct methods: resazurin assay (phase 1) and Colony Forming Unit (CFU) counts (phases 1, 2, and 3). Transversal microradiography and calcium release analysis by atomic absorption spectrometry were chosen to analyze mineral content profile (%vol), integrated mineral loss (IML, %vol x m), lesion depth (LD, m), and concentration of calcium release in culture media (mg/dL). Fluorescence intensity levels, which were modulated by expression of Green Fluorescent Protein-reporter (GFP) after cellular stress, were measured by flow cytometer. A dose-dependent effect on the reduction of viability of planktonic cells and biofilm of S. mutans was observed after application of different parameters of PACT (one-way ANOVA, Games-Howell, p<0.05). 0.25 mg/mL Photogem® plus 150 J/cm2 LED decreased in nearly 3.9 log10 the viability of S. mutans biofilm. Progression of demineralization process was correlated with the time (24 h IML: 1905±391 vol% x m, LD: 69.9±12,2 m; 48 h - IML: 3529±886 vol% x m, LD: 114.2±24.6 m; 72 h - IML: 4186±1099 vol% x m, LD: 146.1±20.1 m). Integrated mineral loss, lesion depth and concentration of calcium release...