Processo de reparo alveolar frente à administração de bifosfonato nitrogenado: avaliação comparativa em camundongos 129/Sv-WT e 129/Sv 5-LOKO / Alveolar bone repair of mice under administration of bisphosphonate containing nitrogen: comparative investigation between 129/Sv-WT and 129/Sv 5- LOKO

A instalação das osteonecroses dos maxilares(OM) tem sido relacionada ao uso crônico de medicamentos antirreabsortivos indicados para doenças e distúrbios do metabolismo ósseo, como os bifosfonatos nitrogenados (nBF), especialmente quando associados a intervenções cirúrgicas-odontológicas. Deste modo, especulase que a instalação desta doença não ocorre somente devido à condição do tecido ósseo e sua capacidade reacional, mas principalmente pela sua condição de defesa imunológica. O presente estudo tem como objetivo analisar o padrão de reparo ósseo de alvéolos dentários de incisivos superiores recém-extraídos de camundongos 129/Sv geneticamente modificados (knockouts ­ KO) para a enzima 5-lipoxigenase (5-LO), os quais apresentam fenótipo esqueletal osteopetrótico, comparando-os com tipo selvagem (Wild Type ­ WT), com e sem administração de nBF. Para tanto foram utilizados 80 camundongos machos com idades variando entre 8 e 10 semanas, sendo 46 animais 129/Sv WT e 46 animais 129/Sv 5-LOKO, os quais foram submetidos à exodontia do dente incisivo superior direito e divididos em quatro grupos de acordo com o tratamento: Grupo WT ­ 0,1 ml de soro fisiológico 0,9%, Grupo WT-ZL ­ 0,5 mg/Kg de ácido zoledrônico (ZL), Grupo 5- LOKO - 0,1 ml de soro fisiológico 0,9%, Grupo 5-LOKO-ZL ­ 0,5 mg/Kg de ZL, sendo ambas soluções administradas intraperitonealmente (IP) 1x por semana até o final do experimento. Após os períodos de 7, 14 e 30 dias, cinco animais de cada grupo foram submetidos à eutanásia para remoção das maxilas direitas contendo os alvéolos para as análises histopatológica, histomorfométrica e imuno-histoquímica para COX-2, OPG, RANKL e TRAP. Os resultados não mostraram diferença significativa para a quantidade de matriz óssea entre os grupos WT, KO e WT-ZL. Contudo, foi observado que o grupo KO-ZL apresentou significativamente menos matriz óssea em todos os períodos quando comparado com WT-ZL, além de maior quantidade de células inflamatórias no 14 e 30 dias. Observou-se aumento significativo de células COX-2+ no grupo WT aos 14 dias em comparação com os demais. Detectou-se aumento de OPG ao final do reparo em todos os grupos. Aumento significativo de RANKL foi observado no grupo KO aos 7 dias, em comparação com 5-LOKO, sendo que ao final do reparo WT-ZL mostrou células RANKL+ significativamente elevadas em comparação com WT e KO-ZL. No entanto, somente aos 14 dias observou-se aumento significativo de células TRAP+ nos grupos WT e WT-ZL em comparação com KO e KO-ZL. A partir destes resultados, pode-se concluir que os animais 5-LOKO apresentaram formação óssea precoce em alvéolos dentários pós-exodontia comparados com os animais WT. No entanto, os efeitos do ZL foram mais deletérios nos camundongos 5-LOKO, possivelmente pela influência da droga e efeitos da inibição desta enzima nos eventos inflamatórios no curso do reparo(AU)

Osteonecrosis of the jaws has been related to the chronic use of antiresorptive drugs indicated for diseases and disorders of bone metabolism, such as nitrogenous bisphosphonates (nBP), especially when associated with surgical-dental interventions. Thus, it is speculated that the onset of this disease does not occur only due to the condition of the bone tissue and its reactive capacity, but mainly due to its immunological defense condition. The present study aimed to analyze the bone repair pattern of dental alveoli of maxillary incisors recently extracted from 129/Sv 5- LOKO mice, which had an osteopetrotic skeletal phenotype, comparing them with wild type, 129/Sv WT, with and without administration of nBP. For that, 80 male mice were used with ages varying between 8 and 10 weeks, being 46 animals 129/Sv WT and 40 animals 129/Sv 5-LOKO, which were submitted to the extraction of the upper right incisor tooth and divided into four groups of according to treatment: WT Group - 0.1 ml of 0.9% saline solution, WT-ZL Group - 0.5 mg/Kg of zoledronic acid, Group 5- LOko - 0.1 ml of 0.9 saline solution %, Group 5-LOko-ZL ­ 0.5 mg/Kg of zoledronic acid, both solutions being administered intraperitoneally (IP) 1x a week until the end of the experiment. After periods of 7, 14 and 30 days, five animals from each group were euthanized to remove the right jaws containing the alveoli. They were immediately fixed in order to be prepared for the following methodological procedures: histotechnical processing for making histological slides stained with hematoxylin and eosin and immunohistochemical No significant difference was found for the amount of bone matrix between the WT, KO and WT-ZL groups. However, it was observed that the KO-ZL group presented significantly less bone matrix in all periods when compared to WT-ZL, in addition to a greater amount of inflammatory cells at 14 and 30 days. There was a significant increase in COX-2+ cells in the WT group at 14 days compared to the others. An increase in OPG was detected at the end of the repair in all groups. Significant increase in RANKL was observed in the KO group at 7 days, compared to 5-LOKO, and at the end of repair WT-ZL showed significantly elevated RANKL+ cells compared to WT and KO-ZL. However, only at 14 days there was a significant increase in TRAP+ cells in the WT and WT-ZL groups compared to KO and KO-ZL. From these results, it can be concluded that 5-LOKO animals showed early bone formation in post-extraction tooth sockets compared to WT animals. However, the effects of ZL were more deleterious in 5-LOKO mice, possibly due to the influence of the drug and the effects of inhibition of this enzyme on inflammatory events in the course of repair(AU)

Efeitos da inibição do receptor 1 de cisteinil leucotrieno e da enzima 5-LO sobre o processo de osseointegração / Effects of inhibition of cysteinyl leukotriene receptor 1 and 5-LO enzyme on the osseointegration process

O presente estudo teve por objetivo avaliar os efeitos da inibição do receptor 1 de cisteinil leucotrieno (CisLT1R) e da enzima 5-lipoxigenase (5-LO) sobre o processo de reparo peri-implantar oral em camundongos. Para tanto, um total de 63 camundongos machos da linhagem 129/Sv foram utilizados, com idades variando de 12 a 14 semanas, sendo 42 animais WT (do inglês Wild Type) e 21 animais geneticamente modificados (knockout-KO) para a enzima 5-LO (5-LOKO), a fim de comporem os seguintes grupos: Controle/WT, MTK/WT e 5-LOKO. Todos os animais foram submetidos ao procedimento cirúrgico para instalação de um micro parafuso de titânio (liga Ti-6Al-4V) na região edêntula da maxila, imediatamente à frente do primeiro molar esquerdo. Previamente ao procedimento cirúrgico, os animais do grupo MTK/WT foram medicados 2 mg/Kg/dia de montelucaste (MTK), via oral, em volume de 10ul, iniciando um dia antes do procedimento e continuando até o final dos períodos experimentais, fixados aos 7, 14 e 30 dias pós-operatórios. Os animais dos grupos Controle/WT e 5-LOKO receberam 10ul de solução fisiológica 0,9%, seguindo o mesmo protocolo dos animais MTK/WT. Completados os períodos, os animais foram submetidos à eutanásia para a coleta das amostras e subsequente processamento para análises histológicas e imunohistoquímicas para avaliação do processo de reparo peri-implantar. Após a obtenção dos dados quantitativos, os mesmos foram submetidos a tratamento estatístico considerando o nível de significância de 5% (p< 0,05). Os animais dos grupos MTK/WT e 5-LOKO apresentaram formação precoce de tecido ósseo ao redor dos implantes, maior número de células COX-2+ e menor de células TRAP+, quando comparados com animais do grupo Controle/WT. Concluiu-se que, a inibição do CisLT1R pelo MTK, bem como a ausência do gene para a 5-LO aceleraram o processo de reparação óssea peri-implantar oral no presente modelo experimental(AU)

The present study aimed to evaluate the effects of inhibition of cysteinyl leukotriene receptor 1 (CisLT1R) and 5-lipoxygenase enzyme (5-LO) on the process of oral periimplant repair in mice. For this purpose, a total of 63 male mice of the 129/Sv strain were used, with ages ranging from 12 to 14 weeks, of which 42 WT (Wild Type) and 21 genetically modified (knockout-KO) animals for the 5-LO enzyme (5-LOKO), in order to compose the following groups: Control/WT, MTK/WT and 5-LOKO. All animals were submitted to a surgical procedure to install a titanium micro screw (Ti6Al-4V alloy) in the edentulous region of the maxilla, immediately in front of the first left molar. Previous to the surgical procedure, the animals in the MTK/WT group were medicated 2 mg/Kg/day of montelukast (MTK), orally, in a 10ul volume, starting one day before the procedure and continuing until the end of the experimental periods, set at 7, 14 and 30 postoperative days. The animals in the Control/WT and 5-LOKO groups received 10ul of 0.9% saline solution, following the same protocol as the MTK/WT animals. After the periods were completed, the animals were euthanized for sample collection and subsequent processing for histological and immunohistochemical analysis to evaluate the peri-implant repair process. After obtaining the quantitative data, they were submitted to statistical treatment considering a significance level of 5% (p< 0.05). Animals in the MTK/WT and 5-LOKO groups showed early bone tissue formation around the implants, higher numbers of COX-2+ cells and fewer TRAP+ cells, when compared to animals in the Control/WT group. It was concluded that, the inhibition of CisLT1R by MTK as well as the absence of the gene for 5-LO accelerated the process of oral peri-implant bone repair in the present experimental model(AU)

Efeito tempo-dose-resposta do montelucaste no processo de reparo alveolar em camundongos 129Sv/Ev / Time-dose-response effect of Montelukast in the process of alveolar repair in 129Sv / Ev mice

Metabólitos do ácido araquidônico são conhecidos por exercerem importante papel nos processos inflamatórios e no metabolismo do tecido ósseo. No entanto, as ações pontuais, especialmente dos leucotrienos derivados da 5-lipoxigenase (5-LO) sobre o processo de reparo ósseo intramembranoso são pouco exploradas. O presente estudo tem como objetivo analisar os efeitos tempo-dose-resposta da droga montelucaste (MTK), potente antagonista dos receptores de cisteinil leucotrienos tipo 1 (CisLT1Rs), no curso do reparo alveolar pós-exodontia em camundongos 129Sv/Ev, bem como nos níveis plasmáticos de marcadores ósseos bioquímicos. Para tanto, foram utilizados 70 camundongos machos jovens divididos em quatro grupos, de acordo com o tratamento: C - Grupo Controle (não tratados); CV - Grupo Controle Veículo, 20 µL de solução fisiológica (SF) 0,9%; MTK2 ­2 mg/kg de MTK e MTK4 ­ 4 mg/kg de MTK. Os animais dos grupos CV, MTK2 e MTK4 foram tratados diariamente por via oral, iniciando 24 horas antes do procedimento cirúrgico, continuando até o final dos períodos experimentais de 7, 14 e 21 dias pós-operatórios. Ao final dos períodos determinados, os animais foram submetidos à eutanásia para coleta de sangue para análise bioquímica dos níveis de cálcio, fosfato, fosfatase ácida resistente ao tartarato (TRAP) total e fosfatase alcalina (FAL), coleta da maxila direita contendo os alvéolos dentários para serem analisados por meio de microtomografia computadorizada (microCT), e análise histopatológica. Os resultados obtidos foram submetidos à testes estatísticos considerando-se nível de confiança de 5%. Observou-se aumento do BV/TV para os animais tratados com MTK em relação aos grupos C e CV, tanto aos 14 dias quanto aos 21 dias, sendo maior no grupo MTK4 aos 14 dias em relação ao grupo MTK2. Do mesmo modo, os animais tratados com MTK em ambas doses apresentaram aumento significativo de Tb.Th em comparação aos grupos C e CV aos 21 dias. Chamou a atenção valores de BV/TV e Tb.Th significativamente reduzidos no grupo CV em comparação ao C, indicando um efeito negativo da manipulação do animal. Na análise histopatológica observou-se reparo ósseo precoce nos animais MTK2 e MTK4 em todos os períodos avaliados, em comparação aos do grupo C, bem como atraso no processo de reparo no grupo CV aos 21 dias. Quanto aos marcadores plasmáticos, observou-se aumento do cálcio no grupo MTK4 em relação ao grupo C aos 7 dias, e aos 21 dias também em relação ao grupo MTK2. Já o fosfato mostrouse significantemente elevado nos períodos de 7 e 21 dias no grupo MTK2 em relação aos demais grupos. FAL e TRAP total não apresentaram níveis plasmáticos significativamente diferentes comparando-se os grupos e períodos. Considerando os resultados obtidos, concluiu-se que o MTK exerceu efeito tempo-dose-dependente, acelerando o processo de reparo ósseo intramembranoso alveolar e interferindo nos níveis plasmáticos de cálcio e fosfato no presente modelo animal(AU)

Arachidonic acid metabolites are known to play an important role in inflammatory processes and in bone metabolism. However, the role of these products on alveolar bone repair post tooth extraction remains to be explored, especially leukotrienes, derived from 5-lipoxygenase (5-LO). The present study aims to analyze the time-doseresponse effects of the drug montelukast (MTK), a potent type 1 leukotriene cystenyl antagonist (CisLT1Rs), in the alveolar repair process after extraction in male 129Sv/Ev mice. For this purpose, 70 young male mice were used, divided into four groups: C - Control Group (no treatment); VC - Vehicle Control Group, treated with 20 µL of 0.9% SF; MTK2 - treated with 2mg / Kg of MTK and MTK4 - treated with 4mg / Kg of MTK. The animals of the CV, MTK2 and MTK4 groups were treated daily orally (V.O.), starting 24 hours before the surgical procedure, continuing until the end of the experimental periods of 7, 14 and 21 days postoperatively. At the end of the experimental periods, the animals were euthanized for blood collection for serum markers as calcium, phosphate, tartrate-resistant acid phosphate (TRAP) and alkaline phosphatasis (FAL), and to removal of the right maxilla containing the dental socket to be analyzed under computed microtomography (microCT) and histopathology. The results obtained were subjected to statistical tests considering a confidence level of 5%. Results revealed an increase in BV/TV for MTK vs. C and CV groups, in both 14 and 21 days time points. Of note, this increase was higher in MTK4 than in the MTK2 at 14 days. Considering Tb.Th, both MTK2 e MTK4 groups presented positive effects in the BV/TV and Tb.Th increase when compared to controls groups (C and CV) at 21 days. A decrease in BV/TV and Tb.Th was observed in CV compared to C, as a negative effect of animal manipulation. As observed in H&E sections, both MTK2 and MTK4 experimental groups presented an early bone repair in comparison with C group from 7 to 21 days. CV group presented a slight delayed bone healing compared to C. Levels of calcium was increased in MTK4 in comparison to C and MTK2 at 7 and 21 days. Phosphate was significantly elevated at 7 and 21 days in MTK2 in comparison to the other groups. Despite of beneficial effects on observed on morphological levels on sites of healing (microCT and HE), no significant changes were found for bone markers of remodeling in blood plasma (FAL and TRAP). Taken together, these results indicate that MTK induced early bone healing post tooth extraction in 129Sv/Ev mice. Thus, the inhibition of CysLT is suggested to exert a positive influence on intramembranous bone repair post tooth extraction(AU)

Rdh13 deficiency weakens carbon tetrachloride-induced liver injury by regulating Spot14 and Cyp2e1 expression levels / 医学前沿

Mitochondrion-localized retinol dehydrogenase 13 (Rdh13) is a short-chain dehydrogenase/reductase involved in vitamin A metabolism in both humans and mice. We previously generated Rdh13 knockout mice and showed that Rdh13 deficiency causes severe acute retinal light damage. In this study, considering that Rdh13 is highly expressed in mouse liver, we further evaluated the potential effect of Rdh13 on liver injury induced by carbon tetrachloride (CCl). Although Rdh13 deficiency showed no significant effect on liver histology and physiological functions under regular culture, the Rdh13 mice displayed an attenuated response to CCl-induced liver injury. Their livers also exhibited less histological changes and contained lower levels of liver-related metabolism enzymes compared with the livers of wild-type (WT) mice. Furthermore, the Rdh13 mice had Rdh13 deficiency and thus their liver cells were protected from apoptosis, and the quantity of their proliferative cells became lower than that in WTafter CCl exposure. The ablation of Rdh13 gene decreased the expression levels of thyroid hormone-inducible nuclear protein 14 (Spot14) and cytochrome P450 (Cyp2e1) in the liver, especially after CCl treatment for 48 h. These data suggested that the alleviated liver damage induced by CCl in Rdh13 mice was caused by Cyp2e1 enzymes, which promoted reductive CCl metabolism by altering the status of thyroxine metabolism. This result further implicated Rdh13 as a potential drug target in preventing chemically induced liver injury.

Liver proteome of mice with different genetic susceptibilities to the effects of fluoride

ABSTRACT A/J and 129P3/J mice strains have been widely studied over the last few years because they respond quite differently to fluoride (F) exposure. 129P3/J mice are remarkably resistant to the development of dental fluorosis, despite excreting less F in urine and having higher circulating F levels. These two strains also present different characteristics regardless of F exposure. Objective In this study, we investigated the differential pattern of protein expression in the liver of these mice to provide insights on why they have different responses to F. Material and Methods Weanling male A/J and 129P3/J mice (n=10 from each strain) were pared and housed in metabolic cages with ad libitum access to low-F food and deionized water for 42 days. Liver proteome profiles were examined using nLC-MS/MS. Protein function was classified by GO biological process (Cluego v2.0.7 + Clupedia v1.0.8) and protein-protein interaction network was constructed (PSICQUIC, Cytoscape). Results Most proteins with fold change were increased in A/J mice. The functional category with the highest percentage of altered genes was oxidation-reduction process (20%). Subnetwork analysis revealed that proteins with fold change interacted with Disks large homolog 4 and Calcium-activated potassium channel subunit alpha-1. A/J mice had an increase in proteins related to energy flux and oxidative stress. Conclusion This could be a possible explanation for the high susceptibility of these mice to the effects of F, since the exposure also induces oxidative stress.

Expression of interferon-induced protein with tetratricopetide repeats 1 and liver cell apoptosis in mice with severe burns / 中南大学学报(医学版)

OBJECTIVE@#To explore the relationship between the expression of interferon-induced protein with tetratricopetide repeats 1 (IFIT1) and liver cell apoptosis in the acute stress period after severe burns.
@*METHODS@#A total of 25 C57/129 adult mice were randomly divided into the normal control group (0 h) and the groups at 1, 6, 12 or 24 after severe burns (n=5 per group). A model with third degree (20% of the total body surface area) burn injury was established and then liver tissues were taken. IFIT1 expression was examined by Western blot. The expression of caspase-3 and -8 was measured by immunohistochemistry. Liver cell apoptosis was detected by terminal deoxynucleotidyl transferase mediated nick end labeling (TUNEL).
@*RESULTS@#After burns, IFIT1 expression was increased at 1 h, which reached the highest level at 
6 h followed by a decrease at 12 h, which reached minimum level at 24 h. The differences between groups were significant (P<0.01). The caspase-3 and -8 levels significantly increased after burns in a time-dependent manner (P<0.01). Although at 0 h and 1 h there was no significant increase in liver cell apoptosis, the increase reached significance from 6 h to 24 h (P<0.01).
@*CONCLUSION@#The increase in IFIT1 expression after severe burns promotes liver cell apoptosis.