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BACKGROUND:Reactive oxygen species may be closely related to the occurrence and development of tendinopathy,but its exact role and related signal transduction mechanism have not been fully summarized. OBJECTIVE:To review current clinical or preclinical original studies,summarize the role of reactive oxygen species in tendinopathy and related signal transduction pathways and to explore its characteristics and whether there is a unified downstream pathway. METHODS:Relevant original studies in PubMed,Embase,Web of Science,as well as CNKI,WanFang,and VIP databases were searched by computer and the search results were screened and excluded according to the inclusion criteria.Ninety articles were finally included for review and analysis. RESULTS AND CONCLUSION:Reactive oxygen species affects the direction of tendon healing by simultaneously acting on tendon cells and the extracellular matrix,and it exhibits a bifacial effect in the treatment of tendinopathy.Concentration of reactive oxygen species may be the key to determining its direction of action.The possibility that low-dose reactive oxygen species can participate in the normal physiological healing of tendons or that tendon tissues are adaptive to stimulations may be the underlying mechanism that produces this characteristic effect.Reactive oxygen species affect the composition and structure of the extracellular matrix and normal tendon repair as well as maintain viability in response to external stimulations through matrix metalloproteinases,mitogen-activated protein kinases,mitochondrial apoptosis,the forkhead transcription factor O family,autophagy,inflammation,and antioxidant signaling pathways.Different reactive oxygen species stimulation intensities,durations,and external environments may cause different alterations in downstream molecular pathways and thus have different effects on the tendon.Due to the large gap in the number of literature included in the evaluation of the positive and negative effects of reactive oxygen species,it may cause some analytical error in the search for factors behind the characteristics of the action of reactive oxygen species in tendon.In addition,most experimental intervention conditions and results of interest are relatively homogeneous;therefore,the temporal and quantitative mechanisms of reactive oxygen species and the synergistic effects with other intervention factors have not been clarified,and the overall system of molecular actions of reactive oxygen species in tendinopathy has not been constructed.To conclude,reactive oxygen species might be involved in the treatment and prevention of tendinopathies as a beneficial factor in the future,and facilitate the exploration of oxidative stress signaling pathways and overall molecular action systems in tendinopathies thereafter,as well as lay the foundation for research on the therapeutic strategies of different antioxidants in tendinopathies to better prevent and treat tendon injury and degeneration.
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BACKGROUND:Increasing studies have found that estrogen has a certain correlation with tendinopathy,but for a long time,there are few experiments and summaries of estrogen in tendinopathy,which makes it difficult for specialists and scholars in related fields to fully understand the research status. OBJECTIVE:To summarize the current clinical or preclinical original research,so as to summarize the role of estrogen in tendinosis,and make a certain prospect for the evaluation and management of estrogen in tendinosis in the future. METHODS:Relevant literature in PubMed,Web of Science,CNKI,WanFang,and VIP databases were searched by computer.Search time was from January 2008 to September 2023.The search terms were"oestrogen,estrogen,estrogen receptor,tendinopathy,tendonopathy,sinew,tendon,tendons,myotenositis"in English and"estrogen,estrogen receptor,tendinosis,tendon,tendinitis"in Chinese.According to the selection criteria,the search results were screened and excluded,and finally 60 documents were included for review and analysis. RESULTS AND CONCLUSION:In vivo studies have shown that estrogen can promote tendon anabolism.In vitro experiments have also proved that various estrogens can promote the proliferation of tendon cells and reduce inflammation and apoptosis,but most of the experiments are limited to animal models.Estrogen receptor β acts more in tendon injury and repair processes,but estrogen receptor α has not been found to have a major impact on tendon injury.The expression of estrogen receptor β can repair the tendon by affecting the formation of fat,the deposition of type I collagen and reducing the apoptosis of tendon cells,while its over-expression may promote inflammation and angiogenesis,thus promoting the inflammatory process and playing a role in tendon injury.Animal studies have shown that estrogen deficiency may reduce the synthesis efficiency of collagen in the tendon,decrease the elasticity of tendon,inhibit the synthesis and metabolism of the tendon,which is not conducive to the repair of tendon injury,while normal level of estrogen may stimulate the synthesis of type I collagen in tendon and promote the proliferation and metabolism of tendon cells.At present,the molecular mechanism of estrogen in tendon injury has not been fully explained.More experiments focus on tendon collagen synthesis,cell proliferation and apoptosis.Only a few documents have studied the molecular mechanisms of estrogen receptor β deficiency regulating interferon regulatory factor 5-chemokine ligand 3 axis,E2 regulating estrogen receptor α and PI-3K-Akt signaling pathways,and high levels of estradiol reducing the level of free-circulating insulin-like growth factor.Various estrogens,including endogenous estrogens and phytoestrogens,are beneficial to the repair of tendinopathy at normal levels,and estrogen receptor β mainly affects the formation of fat,the deposition of type I collagen and the reduction of apoptosis of tendon cells through,which lays a foundation for the future treatment of tendinopathy with different subtypes of estrogens in vivo and the influence of estrogen membrane receptors on tendinopathy.
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<p><b>OBJECTIVE</b>To investigate the expression of manganese superoxide dismutase (MnSOD) and to determine the relationship between MnSOD expression and clinicopathological features, biological behaviors in esophageal carcinoma.</p><p><b>METHODS</b>Immunohistochemistry (SP) and RT-PCR were respectively used to detect the expression of MnSOD in 45 specimens of esophageal carcinoma tissues and normal esophageal mucosa (5 cm distant from the margin of cancer).</p><p><b>RESULTS</b>The positive rate of MnSOD protein expression was 31.1% in esophageal carcinoma tissues, significantly lower than 86.7% in the normal tissues (P < 0.05). The expressions of MnSOD mRNA and protein were significantly correlated with the lesion length, depths of invasion and histological grade (P < 0.05), but not with lymph node metastasis, lesion site and gross type of the tumor (P > 0.05). The relative content of MnSOD mRNA was (0.310 ± 0.036) and (0.482 ± 0.053) in the cancer and normal tissues, respectively, with a significant difference between the two groups (P < 0.05). The relative content of MnSOD mRNA was significantly related to lesion length, depths of invasion and histological grade (P < 0.05), but not correlated with lymph node status, lesion site and gross type of the tumor (P > 0.05).</p><p><b>CONCLUSION</b>The expression of MnSOD protein and mRNA is decreased in esophageal carcinoma, suggesting that MnSOD gene may be closely associated with the carcinogenesis and the degree of malignancy. Detection of MnSOD expression may be useful in diagnosis, treatment and prognosis of esophageal carcinoma.</p>