Objective:To investigate the antioxidant activity of Maca polysaccharides in vitro.Methods:A chemical reaction system was established to explore the scavenging activity of Maca polysaccharides within the concentration range of 0.18-5.00 mg ·ml-1on hydroxyl radicals (·OH),superoxide anion free radicals (O2-·) and DPPH·,and then the total antioxidant capacity was calculated. The protective effects of Maca polysaccharides on H2O2-induced damage in SH-SY5Y cells were determined. SH-SY5Y cells were divided into the control group,H2O2model group and Maca polysaccharide groups(25,50,100 μg·ml-1). In the Maca polysaccharide groups,SH-SY5Y cells were pre-protected by Maca polysaccharides for 24 h, and then incubated in the presence of 300 μmol·L-1H2O2for 6 h. The detection index was SH-SY5Y cell viability detected by MTT assay. Results:Maca polysaccharide within the concentration range of 0.18-5.0 mg·ml-1all exhibited strong scavenging activity on·OH,O2-· and DPPH·in a dose-dependent manner. When the concentration of Maca polysaccharides reached 2.5 mg·ml-1,the scavenging rate was 60.36% for DPPH·,34.66% for O2-·and 36.01% for·OH,the total antioxidant activity was equivalent to 0.179 μmol FeSO4. Maca polysaccharides at the concentration of 25, 50 and 100 μg·ml-1all showed significant protective effects on H2O2-induced injury in SH-SY5Y cells, and the cell survival rate was 61.71 ± 2.45%,61.73 ± 4.51% and 60.98 ± 3.12%, respectively,which were all significantly higher than those in the model group (P < 0.05). Conclusion:Maca polysaccharides has good antioxidant activity,which is worthy of further research and development as a natural antioxidant.

Objective:To investigate whether T-cadherin affects the radiotherapy sensitivity of endometrial cancer cells by regulating the Caspase-1 mediated pyrolysis pathway.Methods:Endometrial cancer and adjacent tissue samples were surgically obtained from 82 patients admitted to Hainan Western Central Hospital from October 2019 to March 2021. Immunohistochemical staining and qRT-PCR were used to detect the expression of T-cadherin in endometrial cancer and adjacent tissue samples. By transfecting pcDNA3.1-T-cadherin lentivirus to human endometrial cancer cell line Ishikawa, a stable Ishikawa cell line with high T-cadherin expression was established. Ishikawa cells were treated with 2 Gy X-ray, and the cell proliferation activity was detected after 24, 48, 72 h of culture. The cells were divided into the control group (normally cultured Ishikawa cells), irradiation group (treated with 2 Gy X-ray irradiation), pcDNA3.1-NC+irradiation group (transfected with pcDNA3.1-NC followed by 2 Gy X-ray irradiation), pcDNA3.1-T-cadherin+irradiation group (transfected with pcDNA3.1-T-cadherin followed by 2 Gy X-ray irradiation), pcDNA3.1-T-cadherin+VA765+irradiation group (transfected with pcDNA3.1-T-cadherin, plus 10 μmol/L VA765 treatment followed by 2 Gy X-ray irradiation). After corresponding treatment, cell survival rate was detected by CCK-8 assay. Cell proliferation was determined by colony formation assay. The level of lactate dehydrogenase (LDH) release was measured by LDH release test. The expression levels of Caspase-1, interleukin (IL)-1β, IL-18 and gasdermin A (GSDMA) were detected by Western blot. The expression level of Caspase-1 was detected by immunofluorescence staining. SPSS 23.0 statistical software was used for data analysis. One-way ANOVA was used for data comparison among multiple groups. LSD- t test was used for two-paired comparison. Results:The positive expression rate of T-cadherin protein in endometrial cancer tissues was 6.09%, lower than 87.80% in adjacent normal tissues ( t=58.48, P<0.01). The relative expression level of T-cadherin mRNA in endometrial cancer tissues was 1.00±0.07, significantly lower than 4.02±0.38 in adjacent normal tissues ( t=32.35, P<0.01). The cell activity of pcDNA3.1-T-cadherin++irradiation group was decreased, the number of cell clones was decreased, LDH release level was increased, the relative expression levels of Caspase-1, IL-1β, IL-18 and GSDMA proteins in cells were up-regulated, and red fluorescence intensity of Caspase-1 protein was enhanced ( P<0.01). However, the cell activity of pcDNA3.1-T-cadherin+VA765+irradiation group was increased, LDH release level was decreased, the relative expression levels of Caspase-1, IL-1β, IL-18 and GSDMA proteins were down-regulated, and the red fluorescence intensity of Caspase-1 protein was also decreased (all P<0.01). Conclusion:T-cadherin can increase the radiotherapy sensitivity of endometrial cancer cells by increasing Caspase-1 mediated pyrolysis.