RESUMO
OBJECTIVE: To study the effect of EGCG on tooth movement and root resorption during orthodontic treatment in rats. METHODS: A total of thirty six male Wistar rats were randomly and equally divided into three groups: control, 50 mg/kg EGCG, and 100 mg/kg EGCG. During the experiment, the subjects were submitted to an orthodontic tooth movement (OTM) model, rats in the experimental groups were given the corresponding dose of EGCG, while rats in the control group were administrated with an equal volume of normal saline solution by gavage. After 14 days of OTM, the rats were sacrificed by transcardial perfusion. Micro-CT of rat maxillaes was taken to analyze OTM distance and root resorption. The maxillary samples were prepared as histological sections for H&E staining, tartrate-resistant acid phosphatase (TRAP) staining and immunohistochemical (IHC) staining to be observed and analyzed. RESULTS: The OTM distance and root resorption of rats in the dosed group decreased, and the number of TRAP positive cells in their periodontium decreased significantly. The expression level of RANKL was decreased in the EGCG group compared to the control group, while that of OPG, OCN and Runx2 was increased. Effects were more pronounced in 100 mg/kg group than in 50 mg/kg group. CONCLUSION: EGCG reduces OTM and orthodontic induced root resorption (OIRR) in rats, and is able to attenuate osteoclastogenesis on the pressure side and promote osteogenesis on the tension side.
Assuntos
Reabsorção da Raiz , Ratos , Masculino , Animais , Reabsorção da Raiz/tratamento farmacológico , Ratos Wistar , Osteoclastos , Técnicas de Movimentação Dentária , Chá , Raiz DentáriaRESUMO
Chlorophyll content is a physiological index widely used in the research of botany and agriculture. It is closely associated with leaf photosynthetic function. The current methods cannot simultaneously determine chlorophyll content and photosynthetic function and analyze their correlation. To solve this problem, we measured the SPAD value and chlorophyll fluorescence induction kinetic curve with 35 wheat varieties. We established a linear regression model using the fluorescence values of the fast chlorophyll fluorescence kinetic curve at different times, 33 common fluorescence parameters, and the correlation between the parameters and the SPAD values. We further verified the model using laboratory and field data. Our results showed that the linear model based on chlorophyll fluorescence parameter RC/CSm could reliably predict the SPAD value of the leaves, which could be used to estimate the relative content of chlorophyll in wheat leaves under non-severe stress. The linear model enriched the method of nondestructive measurement of chlorophyll relative content in wheat, simplified the experimental flow, and achieved the simultaneous determination and analysis of wheat photosynthesis function and chlorophyll content.
Assuntos
Clorofila , Triticum , Fluorescência , Fotossíntese , Folhas de PlantaRESUMO
Cultivar renewing is important for the increases of wheat yield. Studying changes of different physiological characteristics in the succession process of wheat varieties has great implications for future breeding. The senescence rate of flag leaf is a key factor affecting winter wheat yield. The variation of photosystem II function during senescence of flag leaves of wheat from different ages is still not clear. 31 wheat varieties planted in Henan Province from different ages since 1941 were examined in this experiment. The variation of photosystem II function was analyzed through measu-ring the relative chlorophyll content, and chlorophyll fluorescence induction dynamics during the senescence of flag leaves which were induced by continued dark. The results showed that the chlorophyll content of flag leaves was gradually increased in the succession of winter wheat. The chlorophyll degradation rate in the leaves of modern varieties was lower than the earlier varieties during the senescnece of flag leaves. Meanwhile, J point of the fluorescence induction kinetics curves in flag leaves of modern varieties increased less than I point. The photosystem II maximum photochemical efficiency and the amount of active reaction centers per unit area gradually increased during succession of wheat varieties, but the reduced extent in leaves of modern varieties was lower than that in the earlier ones. There was no significant correlation between the change of chlorophyll content and Fv/Fm in senescent leaves. There was significant positive correlation when the leaves aging degree increased, with the slope of trend line gradually increased. The photosystem II unit area and the amount of active reaction center was positively related with the aging degree, and both the correlation degree and slope of trend line increased with the increases of senescence extent of the leaves. The results suggested that chlorophyll content of flag leaf increased and the degradation rate slowed down gradually during the succession of wheat varieties. The anti-aging ability of photosynthetic electron transfered from QA to QB was improved, which contributed to the slowing down of the decline of Fv/Fm and the amount of active reaction center. The increased chlorophyll content and anti-aging ability of photosystem II also contributed to the increases of yield in the succession of winter wheat.
