Maternal methionine supplementation in mice affects long-term body weight and locomotor activity of adult female offspring.

Methionine is a precursor of s-adenosylmethionine, the main donor of methyl radicals for methylation of DNA and other compounds. Previous studies have shown that reduced availability of methyl radicals during pregnancy/lactation decreased offspring perigonadal white adipose tissue (PWAT) and body weight. Therefore, we aimed to evaluate the effects of methionine supplementation during early development, a time of great ontogenic plasticity, by assessing the biometric, biochemical and behavioural parameters of the offspring of adult Swiss female mice supplemented with 1 % methionine in water 1 month before pregnancy, during pregnancy or pregnancy/lactation. After birth, the offspring were distributed into three groups: control (CT), methionine supplementation during pregnancy (SP) and methionine supplementation during pregnancy and lactation (SPL), and were followed until postnatal day (PND) 300. No changes were observed in offspring birth weight in both sexes. At PND 5, 28 and 90, no differences in body weight were found in females; however, at PND 300, SP and SPL females showed an increase in body weight when compared with the control group. This increase in body weight was accompanied by a total and relative increase in PWAT, and a decrease in locomotor activity in these groups. No differences in the body and organ weights were found in male offspring. In conclusion, the increased availability of methyl radicals during pregnancy and lactation impacted long-term body composition and locomotor activity in female offspring.

Treatment of experimental periodontal disease by laser therapy in simvastatin-modified rats.

OBJECTIVE: The aim of this study was to evaluate low-level laser therapy (LLLT) as an adjuvant treatment for scaling and root planing (SRP) for the treatment of induced periodontitis in simvastatin-modified rats. MATERIAL AND METHODS: A total of 180 rats were evenly divided into two groups: Veh - receiving oral administration of polyethylene glycol (vehicle); S - receiving oral administration of Simvastatin. Periodontal disease was induced in both groups at the first mandibular molar. After seven days, the ligature was removed and the animals were divided into subgroups according to the following local treatments: NT - no treatment; SRP - scaling and root planing and irrigation with saline solution; and LLLT ¬- SRP and laser irradiation (660 nm; 0.03 W; 4 J). Ten animals in each subgroup/local treatment were euthanized at 7, 15 and 30 days. Samples of gingival tissue were processed to analyze the tissue oxidative damage and radiographic analysis. Levels of oxidative stress were analyzed by the expressions of Tripeptideglutathione (TG), Malondialdehyde (MDA) and Carbonylated Proteins (CP). RESULTS: The animals in S group had higher levels of TG and lower levels of MDA and CP compared with Veh group (p<0.05). Radiographically, in the intragroup analysis Veh and S, LLLT showed lower bone loss (BL) compared with NT and SRP, in all experimental periods (p<0.01). In addition, a lower BL was observed for the animals of Veh group treated with LLLT compared with treatment SRP in the S group, in all experimental periods. CONCLUSION: Within the limits of this study, we can conclude that LLLT was effective as adjuvant treatment for SRP protecting against the occurrence of oxidative tissue damages as well as for reducing alveolar bone loss in experimentally induced periodontitis simvastatin-modified rats.

Treatment of experimental periodontal disease by laser therapy in simvastatin-modified rats

Abstract Low intensity laser can be used as a promising alternative in the treatment of periodontal disease. Objective The aim of this study was to evaluate low-level laser therapy (LLLT) as an adjuvant treatment for scaling and root planing (SRP) for the treatment of induced periodontitis in simvastatin-modified rats. Material and Methods A total of 180 rats were evenly divided into two groups: Veh - receiving oral administration of polyethylene glycol (vehicle); S - receiving oral administration of Simvastatin. Periodontal disease was induced in both groups at the first mandibular molar. After seven days, the ligature was removed and the animals were divided into subgroups according to the following local treatments: NT - no treatment; SRP - scaling and root planing and irrigation with saline solution; and LLLT ¬- SRP and laser irradiation (660 nm; 0.03 W; 4 J). Ten animals in each subgroup/local treatment were euthanized at 7, 15 and 30 days. Samples of gingival tissue were processed to analyze the tissue oxidative damage and radiographic analysis. Levels of oxidative stress were analyzed by the expressions of Tripeptideglutathione (TG), Malondialdehyde (MDA) and Carbonylated Proteins (CP). Results The animals in S group had higher levels of TG and lower levels of MDA and CP compared with Veh group (p<0.05). Radiographically, in the intragroup analysis Veh and S, LLLT showed lower bone loss (BL) compared with NT and SRP, in all experimental periods (p<0.01). In addition, a lower BL was observed for the animals of Veh group treated with LLLT compared with treatment SRP in the S group, in all experimental periods. Conclusion Within the limits of this study, we can conclude that LLLT was effective as adjuvant treatment for SRP protecting against the occurrence of oxidative tissue damages as well as for reducing alveolar bone loss in experimentally induced periodontitis simvastatin-modified rats.

MCH levels in the CSF, brain preproMCH and MCHR1 gene expression during paradoxical sleep deprivation, sleep rebound and chronic sleep restriction.

Neurons that utilize melanin-concentrating hormone (MCH) as neuromodulator are located in the lateral hypothalamus and incerto-hypothalamic area. These neurons project throughout the central nervous system and play a role in sleep regulation. With the hypothesis that the MCHergic system function would be modified by the time of the day as well as by disruptions of the sleep-wake cycle, we quantified in rats the concentration of MCH in the cerebrospinal fluid (CSF), the expression of the MCH precursor (Pmch) gene in the hypothalamus, and the expression of the MCH receptor 1 (Mchr1) gene in the frontal cortex and hippocampus. These analyses were performed during paradoxical sleep deprivation (by a modified multiple platform technique), paradoxical sleep rebound and chronic sleep restriction, both at the end of the active (dark) phase (lights were turned on at Zeitgeber time zero, ZT0) and during the inactive (light) phase (ZT8). We observed that in control condition (waking and sleep ad libitum), Mchr1 gene expression was larger at ZT8 (when sleep predominates) than at ZT0, both in frontal cortex and hippocampus. In addition, compared to control, disturbances of the sleep-wake cycle produced the following effects: paradoxical sleep deprivation for 96 and 120 h reduced the expression of Mchr1 gene in frontal cortex at ZT0. Sleep rebound that followed 96 h of paradoxical sleep deprivation increased the MCH concentration in the CSF also at ZT0. Twenty-one days of sleep restriction produced a significant increment in MCH CSF levels at ZT8. Finally, sleep disruptions unveiled day/night differences in MCH CSF levels and in Pmch gene expression that were not observed in control (undisturbed) conditions. In conclusion, the time of the day and sleep disruptions produced subtle modifications in the physiology of the MCHergic system.

Detraining in pregnancy and/or lactation modulates neuropeptidergic hypothalamic systems in offspring mice.

Manipulations in metabolic parameters during pregnancy/lactation can impact the development of short- and long-term energy control mechanisms, which are mainly modulated by neural and hormonal inputs to the hypothalamus. Thus, we tested how mice training and detraining during pregnancy and lactation affect hypothalamus gene expression and change biometric and metabolic profiles of the offspring. Three-month-old female Swiss mice were submitted to an 8-week exercise program (swimming 5 times/week, 1 h/day). Following this physical exercise protocol, these conditioned animals and the control group were submitted to matting. After pregnancy verification, the animals were distributed into four groups: training during pregnancy and lactation (T); detraining after pregnancy confirmation (DP); detraining during lactation (DL); and control (CT), without interventions. After weaning, the offspring of the four groups were derived into these as follows: TO, DPO, DLO, and CTO, respectively. The body weight was lower in conditioned females compared to control at weeks 4-8 of the exercise regimen. No statistical difference in dam's body weight was observed during pregnancy. Related to offspring, at post-natal day 90, the animals were euthanized and DPO and DLO showed decrease in Npy and Cart expression in hypothalamus, and DLO also had increased Lep gene expression in white adipose tissue. Additionally, DPO showed increase in plasma triglycerides levels, total liver weight, and decrease in brown adipose tissue compared to CTO. Together, these results support that detraining during critical periods of development leads to altered gene expression in hypothalamic neuropeptidergic systems.

Effect of LLLT on autogenous bone grafts in the repair of critical size defects in the calvaria of immunosuppressed rats.

The aim of this study was to evaluate the effects of low-level laser therapy (LLLT) on the bone repair of critical size defects (CSDs) filled with autogenous bone in the calvaria of immunosuppressed rats. A 5 mm-diameter CSD was created in the calvaria of 30 rats. The animals were divided into 5 groups (n = 6): Control (C)--the defect was filled with a blood clot; Dexamethasone (D)--dexamethasone treatment, and the defect was filled with a blood clot; Autogenous bone (AB)--dexamethasone treatment, and the defect was filled with autogenous bone; LLLT--dexamethasone treatment, and the defect received LLLT (660 nm; 35 mW; 24.7 J/cm(2)); and AB + LLLT--dexamethasone treatment, and the defect was filled with autogenous bone and received LLLT. All animals were euthanized at 30 postoperative days. Histometric and histological analyses were performed. The new bone area (NBA) was calculated as the percentage of the total area of the original defect. Data were analysed statistically (an analysis of variance and Tukey's test; P < 0.05). The AB + LLLT group showed the largest NBA of all groups (P < 0.05). The use of LLLT with AB effectively stimulated bone formation in CSDs in the calvaria of immunosuppressed rats.

Effects of LLLT in combination with bisphosphonate on bone healing in critical size defects: a histological and histometric study in rat calvaria.

The purpose of this study was to analyze histologically the effect of low-level laser therapy (LLLT) in combination with bisphosphonate on bone healing in surgically created critical size defects (CSD) in rat calvaria. One hundred Wistar female rats sham operated (sham) and ovariectomized (Ovx) were maintained untreated for 1 month to allow for the development of osteopenia in the Ovx animals. A CSD was made in the calvarium of each rat, and the animals were divided into five groups according to following treatments: (1) sham rats (control), (2) Ovx rats, (3) Ovx rats treated with LLLT, (4) Ovx rats treated with bisphosphonate, and (5) Ovx rats treated with bisphosphonate and LLLT. Groups 4 and 5 were irrigated with 1 ml of bisphosphonate, and groups 3 and 5 were submitted to LLLT (GaAlAs), 660 nm, 24 J, and 0.4285 W/cm(2) on the CSD. Ten animals of each treatment were killed at 30 and 60 days. Histomorphometric assessments, using image analysis software, and histological analyses were performed. No defect was completely regenerated with the bone. Histometrically, it can be observed that groups 3 (37.49 ± 1.94%, 43.11 ± 2.39%) and 5 (35.05 ± 1.57%, 41.07 ± 1.89%) showed a significant bone neoformation when compared to groups 1 (16.81 ± 1.57%, 27.54 ± 1.49%), 2 (11.68 ± 0.98%, 22.51 ± 1.05%), and 4 (14.62 ± 1.70%, 25.67 ± 1.41%) in all experimental periods (P < 0.05). It was possible to conclude that the LLLT associated or not with bisphosphonate treatment was effective for stimulating bone formation in CSD in the calvaria of rats submitted to ovariectomy.

Adjunctive antimicrobial photodynamic treatment of experimentally induced periodontitis in rats with ovariectomy.

BACKGROUND: The aim of this study is to compare antimicrobial photodynamic therapy (aPDT) as an adjunctive therapy to scaling and root planing (SRP) for the treatment of experimentally induced periodontitis in rats with ovariectomy (OVX) that are or are not treated with estrogen replacement. METHODS: A total of 270 female rats were divided into three groups: 1) normal rats; 2) rats with OVX; and 3) rats with OVX with estrogen replacement. Periodontal disease was induced through the introduction of a cotton thread around the mandibular left first molar. After 7 days, the ligature was removed, and the rats were randomly divided into the following treatment groups: 1) SRP plus saline solution; 2) SRP plus low-level laser therapy (LLLT); and 3) SRP plus toluidine blue O irrigation followed by LLLT. Ten rats from each group were euthanized at days 7, 15, and 30 after dental treatment. Bone loss (BL) in the furcation region was evaluated using histometric and immunohistochemical analyses. RESULTS: aPDT treatment resulted in reduced BL compared with SRP treatment at all time points. Additionally, rats treated with aPDT exhibited reduced numbers of tartrate-resistant acid-phosphatase-positive cells and more proliferating cell nuclear antigen-positive cells in all treatment groups regardless of estrogen status. Whereas rats treated with aPDT showed weak immunoreactivity to the receptor activator of nuclear factor-κ B ligand at day 7 post-treatment, strong osteoprotegerin immunoreactivity was observed at day 15 post-treatment. CONCLUSION: aPDT is an effective adjunctive therapy for the treatment of periodontitis in rats with OVX that are or are not given estrogen replacement therapy.

Biomechanical effect of one session of low-level laser on the bone-titanium implant interface.

Low-level laser (LLL) has been used on peri-implant tissues for accelerating bone formation. However, the effect of one session of LLL in the strength of bone-implant interface during early healing process remains unclear. The present study aims to evaluate the removal torque of titanium implants irradiated with LLL during surgical preparation of implant bed, in comparison to non-irradiation. Sixty-four Wistar rats were used. Half of the animals were included in LLL group, while the other half remained as control. All animals had the tibia prepared with a 2 mm drill, and a titanium implant (2.2 × 4 mm) was inserted. Animals from LLL group were irradiated with laser (gallium aluminum arsenide), with a wavelength of 808 nm, a measured power output of 50 mW, to emit radiation in collimated beams (0.4 cm(2)), for 1 min and 23 s, and an energy density of 11 J/cm(2). Two applications (22 J/cm(2)) were performed immediately after bed preparation for implant installation. Flaps were sutured, and animals from both groups were sacrificed 7, 15, 30, and 45 days after implant installation, when load necessary for removing implant from bone was evaluated by using a torquimeter. In both groups, torque values tended to increase overtime; and at 30 and 45 days periods, values were statistically higher for LLL group in comparison to control (ANOVA test, p < 0.0001). Thus, it could be suggested that a single session of irradiation with LLL was beneficial to improve bone-implant interface strength, contributing to the osseointegration process.

Treatment of experimental periodontitis in rats using repeated adjunctive antimicrobial photodynamic therapy.

The aim of this study was to histologically and histometrically evaluate the influence of repeated adjunctive antimicrobial photodynamic therapy (aPDT) on bone loss (BL) in furcation areas in rats. Periodontitis was induced by placing a ligature around the mandibular molar in 75 rats. The animals were divided into five groups: the SS group was treated with saline solution (SS); the SRP group received scaling and root planing (SRP); the aPDT1 group received SRP as well as toluidine blue (TBO) and low-level laser therapy (LLLT; InGaAlP, 660 nm; 4.94 J/cm(2)/point) postoperatively at 0 h; the aPDT2 group received SRP as well as TBO and LLLT postoperatively at 0, 24, 28, and 72 h; and the aPDT3 group received SRP, TBO, and LLLT postoperatively at 0, 48, 96, and 144 h. The area of BL in the furcation region of the molar was histometrically analyzed. Data were analyzed statistically (P < 0.05). Animals treated with a single episode of aPDT showed less BL at days 7 and 30 than those who received only SRP treatment. No significant differences were found among the aPDT groups (P > 0.05). Repeated aPDT did not improve BL reduction when compared to a single episode of aPDT.

Efeito da aPDT na osseointegração de implantes em alvéolos contaminados / Effect of aPDT in the osseointegration of implants in contaminated dental sockets

Objetivo: Avaliar por meio de análises histométrica e imuno-histoquímica os efeitos da terapia fotodinâmica antimicrobiana (aPDT) no tratamento alveolar prévio à colocação de implantes, em alvéolos de dentes de ratos portadores ou não de doença periodontal induzida. Material e método: Trinta e dois ratos foram utilizados no estudo. A doença periodontal foi induzida nos primeiros molares inferiores esquerdos. Decorridos sete dias, foi realizada a remoção da ligadura e a exodontia dos primeiros molares inferiores direitos e esquerdos. A seguir, os animais foram divididos em dois grupos de 16 animais, de acordo com os tratamentos realizados nos alvéolos dentais antes da instalação do implante imediato: DM-debridamento mecânico (DM), irrigação com 1 mL de soro fisiológico seguida de instalação do implante; aPDT-DM, irrigação com 1 mL de azul de toluidina O (TBO) e, após 1 minuto, irradiação com laser em baixa intensidade (LLLT). Oito animais de cada grupo foram eutanasiados aos 15 e 30 dias. Os espécimes foram processados laboratorialmente para análises histométrica do contato osso-implante (BIC) e imuno-histoquímica. Os dados histométricos foram estatisticamente analisados (Teste Kruskall-Wallis e Dunn p < 0,05). Resultado: Na análise dos tratamentos, os resultados demonstraram que houve maior BIC nos implantes instalados em alvéolos não contaminados tratados com aPDT (p < 0,05) e maior imunorreatividade à OPG no tecido ósseo tratado com aPDT. Conclusão: A aPDT mostrou-se efetiva no controle da perda óssea em áreas não contaminadas e aumentou a atividade metabólica e a atividade das células ósseas nos alvéolos irradiados previamente à instalação dos implantes.

Objective: The aim of this study is to evaluate by histometric and immunohistochemistry analysis the effects of antimicrobial photodynamic therapy (aPDT) in alveolar prior to placement of mini-implants in animals with or without induced periodontal disease. Material and method: Thirty-two rats were used. Periodontal disease (PD) was induced by ligature in the lower left first molar. After 7 days of PD evolution, it was performed removal of the ligature and extraction of the left lower first molars in all animals. Thus, animals were divided into 2 groups (n = 16) according to the treatments in the dental alveolus before immediate implant installation: MD (control) : mechanical debridement (MD), irrigation with 1 mL of saline solution followed by implant installation; aPDT-MD, irrigation with 1 mL of Toluidine Blue-O and low intensity laser (LLLT) and implant installation. Eight animals from each group were euthanized at 15 and 30 days after the installation of mini-implants. Specimens were processed for histologic, immunohistochemical and histometric analysis. The histometric data were processed for statistical analysis (Kruskall-Wallis and Dunn test; p < 0.05). Result: In treatment analysis, results indicated thatthere was a greater BIC in implants installed in uncontaminated alveolus treated with a PDT ( p < 0.05) and greater imuno-reactivity to OPG in bone issue treated with aPDT. Conclusion: The aPDT proved to be effective in bone loss control in no contaminated area and it has increased the bone loss and metabolic activity in alveolus irradiated prior to implant installation.

Treatment of experimental periodontal disease by a selective inhibitor of cyclooxygenase-2 with scaling and root planing (SRP).

Lumiracoxib is a selective inhibitor of cyclooxygenase-2 (COX-2) approved for the relief of symptoms of chronic inflammatory conditions. The aim of this study was to evaluate the effects of this specific inhibitor of COX-2 as adjunctive treatment on induced periodontitis in rats. Periodontal disease was induced at the first mandibular molar of 60 rats. After 7 days, the ligature was removed and all animals were submitted to scaling and root planing (SRP) along with local irrigation with saline solution and were divided into 2 groups: SRP (n = 30)-received subcutaneous injections of 1 mg/kg of body weight/day of saline solution for 3 days and; SRP + L (n = 30)-received subcutaneous injections of 1 mg/kg of body weight/day of Lumiracoxib for 3 days. Ten animals in each group were killed at 7, 15, and 30 days. The histological description was performed and the histometric values were statistically analyzed. In Group SRP + L, the histometric analysis (0.58 ± 0.08, 0.64 ± 0.06, and 0.56 ± 0.10 mm(2)) showed less bone loss (p < 0.05) than Group SRP (1.52 ± 0.08, 1.55 ± 0.09, and 1.49 ± 0.24 mm(2)) at 7, 15, and 30 days, respectively. Within the limits of this study it can be concluded that subcutaneous application of specific inhibitor of COX-2 was a beneficial adjunctive treatment for periodontal diseases induced in rats.

Radiographic assessment of photodynamic therapy as an adjunctive treatment on induced periodontitis in immunosuppressed rats.

OBJECTIVE: The aim of this study was to assess radiographically the effect of photodynamic therapy (PDT) as an adjunctive treatment to scaling and root planing (SRP) on induced periodontitis in dexamethasone-induced immunosuppressed rats. MATERIAL AND METHODS: The animals were divided into 2 groups: ND group (n=60): saline treatment; D group (n=60): dexamethasone treatment. In both ND and D groups, periodontal disease was induced by the placement of a ligature in the left first mandibular molar. After 7 days, ligature was removed and all animals received SRP, being divided according to the following treatments: SRP: saline and PDT: phenothiazinium dye (TBO) plus laser irradiation. Ten animals per treatment were killed at 7, 15 and 30 days. The distance between the cementoenamel junction and the height of the alveolar bone crest in the mesial surface of the mandibular left first molars was determined in millimeters in each radiograph. he radiographic values were analyzed statistically by ANOVA and Tukey's test at a p value <0.05. RESULTS: Intragroup radiographic assessment (ND and D groups) showed that there was statistically significant less bone loss in the animals treated with PDT in all experimental periods compared to those submitted to SRP. Intergroup radiographic analysis (ND and D groups) demonstrated that there was greater bone loss in the ND group treated with SRP compared to the D group treated with PDT at 7 and 30 days. CONCLUSION: PDT was an effective adjunctive treatment to SRP on induced periodontitis in dexamethasone-induced immunosuppressed rats.

Estudo histomorfométrico do processo de cicatrização óssea em defeitos cirúrgicos de tamanho crítico em calvárias de ratos preenchidos com polímero de mamona / Histomorphometric study of bone healing process in surgical defects of critical size rat calvarial filled with castor oil polymer

Introdução: O objetivo do presente estudo foi avaliar histomorfometricamente o comportamento do polímero de mamona durante o processo de cicatrização de defeitos de tamanho crítico preparados em calvárias de ratos. Materiais e Métodos: Vinte animais foram submetidos a um procedimento cirúrgico que consistiu em se realizar na calvária de cada animal um defeito crítico de 8 mm de diâmetro com uma broca trefina. Os ratos foram divididos em dois grupos de acordo com os seguintes procedimentos: Grupo C, não receberam nenhum tratamento local e o defeito ósseo foi preenchido com coágulo sanguíneo; Grupo M, o defeito ósseo foi preenchido com partículas de polímero de mamona. Os animais foram sacrificados 180 dias após os procedimentos cirúrgicos. Após os procedimentos laboratoriais de rotina as peças foram submetidas à análise histomorfométrica. Resultados: Nos animais do Grupo C o tecido ósseo neoformado mostrou-se bem desenvolvido, com áreas adjacentes de matriz osteóide rica em osteoblastos, e restrito às proximidades das bordas do defeito. Nos animais do Grupo M observou-se tecido ósseo lamelar neoformado restrito às proximidades das bordas do defeito e partículas de Polímero de Mamona distribuídas ao longo do defeito. Houve uma maior porcentagem de área de osso neoformado estatisticamente significante nos animais do Grupo C comparado aos animais do Grupo M. Conclusão: Dentro dos limites deste estudo pode-se concluir que o polímero de mamona apresentou-se biocompatível e manteve o espaço durante o processo de cicatrização de defeitos de tamanho crítico cirurgicamente preparadas em calvárias de ratos

Objectives: The aim of this study was to evaluate the behavior of the polymer histomorphometrically castor during the healing process of defects of critical size calvarial preparations in rats. Materials and Methods: Twenty animals underwent a surgical procedure that was to be held in the calvaria of each animal a critical defect of 8 mm in diameter with a drill trephine. The rats were divided into two groups according to the following procedures: group C received no treatment and the bone defect site was filled with blood clot, group M, the bone defect was filled with castor oil polymer particles. The animals were sacrificed 180 days after the surgical procedures. After routine laboratory procedures the specimens were subjected to analysis histomorphometric. Results: In groups C the newly formed bone tissue was well developed, with adjacent areas of osteoid matrix rich in osteoblasts, and restricted to the vicinity of the edges of the defect. In animals of group M was observed newly formed lamellar bone tissue restricted to the vicinity of the defect edges and particles of polymer Castor distributed throughout the defect. There was a higher percentage of newly formed bone area was statistically significant in group C compared to animals in group M. Conclusions: Within the limits of this study can conclude that the castor oil polymer is biocompatible and had kept the area during the healing of critical size defects in surgically prepared rat calvariae

Radiographic assessment of photodynamic therapy as an adjunctive treatment on induced periodontitis in immunosuppressed rats

OBJECTIVE: The aim of this study was to assess radiographically the effect of photodynamic therapy (PDT) as an adjunctive treatment to scaling and root planing (SRP) on induced periodontitis in dexamethasone-induced immunosuppressed rats. MATERIAL AND METHODS: The animals were divided into 2 groups: ND group (n=60): saline treatment; D group (n=60): dexamethasone treatment. In both ND and D groups, periodontal disease was induced by the placement of a ligature in the left first mandibular molar. After 7 days, ligature was removed and all animals received SRP, being divided according to the following treatments: SRP: saline and PDT: phenothiazinium dye (TBO) plus laser irradiation. Ten animals per treatment were killed at 7, 15 and 30 days. The distance between the cementoenamel junction and the height of the alveolar bone crest in the mesial surface of the mandibular left first molars was determined in millimeters in each radiograph. he radiographic values were analyzed statistically by ANOVA and Tukey's test at a p value <0.05. RESULTS: Intragroup radiographic assessment (ND and D groups) showed that there was statistically signifcant less bone loss in the animals treated with PDT in all experimental periods compared to those submitted to SRP. Intergroup radiographic analysis (ND and D groups) demonstrated that there was greater bone loss in the ND group treated with SRP compared to the D group treated with PDT at 7 and 30 days. CONCLUSION: PDT was an effective adjunctive treatment to SRP on induced periodontitis in dexamethasone-induced immunosuppressed rats.

Comparison between laser therapy and non-surgical therapy for periodontitis in rats treated with dexamethasone.

The aim of this study was to compare low-level laser therapy (LLLT) as adjuvant treatment for induced periodontitis with scaling and root planing (SRP) in dexamethasone-treated rats. One-hundred twenty rats were divided into groups: D group (n = 60), treated with dexamethasone; ND group (n = 60) treated with saline solution. In both groups, periodontal disease was induced by ligature at the left first mandibular molar. After 7 days, the ligature was removed and all animals were subjected to SRP and were divided according to the following treatments: SRP, irrigation with saline solution (SS); SRP + LLLT, SS and laser irradiation (660 nm; 24 J; 0.428 W/cm(2)). Ten animals in each treatment were killed after 7 days, 15 days and 30 days. The radiographic and histometric values were statistically analyzed. In all groups radiographic and histometric analysis showed less bone loss (P < 0.05) in animals treated with SRP + LLLT in all experimental periods. SRP + LLLT was an effective adjuvant conventional treatment for periodontitis in rats treated with dexamethasone.

Effect of photodynamic therapy on the healing of cutaneous third-degree-burn: histological study in rats.

The aim of this study was to conduct a histological assessment of the effect of photodynamic therapy (PDT) on the repairing of third-degree-burn wounds made on the backs of rats with a heated scalpel. Ninety-six rats were divided into groups: G1, control (n = 24), cold scalpel; G2, burned, heated scalpel (n = 24); G3, low-level laser therapy (LLLT) (n = 24), on burns; and G4, photodynamic therapy (PDT) (n = 24), toluidine-O blue (100 microg/ml) and LLLT treatment on burns. The laser (685 nm) was applied in continuous mode, 50 mW, 4.5 J/cm(2), contact mode at nine points (9 s/point). Eight animals in each group were killed at 3 days, 7 days or 14 days after surgery, and tissue specimens containing the whole wounded area were removed and processed for histological analysis; the results were statistically analyzed with Kruskal-Wallis and Dunn's tests (P < 0.05). The results demonstrated significant differences between G2 and G3, and between G2 and G4, at both 3 days and 7 days, with regard to acute inflammation scores; G1 and G2 showed significant differences when compared with G4 at 3 days, with regard to neo-angiogenesis scores; G1 and G2 were statistically different from G3 and G4 at both 3 days and 7 days, with regard to re-epithelization scores; G2 showed statistically significant differences when compared with G3 and G4 with regard to collagen fiber scores at 7 days. LLLT and PDT acted as a biostimulating coadjuvant agent, balancing the undesirable effect of the burn on the wound healing process, acting mainly in the early healing stages, hastening inflammation and increasing collagen deposition.

Treatment of experimental periodontal disease by photodynamic therapy in immunosuppressed rats.

BACKGROUND AND OBJECTIVE: The aim of this study was to compare photodynamic therapy (PDT) as an adjunctive treatment of induced periodontitis with scaling and root planing (SRP) in dexamethasone-inhibited rats. MATERIAL AND METHODS: The animals were divided into two groups: ND (n=90), saline solution treatment; D (n=90), dexamethasone treatment. In the ND and D Groups, periodontal disease was ligature-induced at the first mandibular molar. After 7 days, the ligature was removed and all animals received SRP and were divided according to the following treatments: SRP, saline solution; Toluidine Blue-O (TBO), phenothiazinium dye; and PDT, TBO and laser irradiation. Ten animals in each treatment were killed at 7, 15 and 30 days. The radiographic and histometric values were statistically analysed. RESULTS: In the ND and D Groups, radiographic analysis showed less bone loss in animals treated by PDT in all the experimental periods than SRP and TBO at 15 days (p<0.05). After a histometric analysis was carried out in the ND and D groups, the animals treated by PDT showed less bone loss in all periods than SRP and TBO after 15 days (p<0.05). CONCLUSIONS: The PDT was an effective adjunctive treatment of induced periodontitis compared with SRP in dexamethasone-inhibited rats.