ABSTRACT
Objective:To investigate the effects of thioredoxin reductase 1(TR1) overexpression on hippocampus in ovariectomized SD rats.Methods:Totally 54 female SD rats were divided into normal group, ovariectomized group and ovariectomized over-expressioned TR1 group (ovariectomy-TR1 group) according to the random number table method with 18 in each group. The overexpressed TR1 vector was constructed by lentivirus, and the recombinant lentivirus was injected into the hippocampus by a brain stereotactic instrument.The mRNA levels and protein levels of TR1, Bcl-2, p53 and p21 in the hippocampus of SD rats were detected by qRT-PCR and Western blot.The expression of Caspase-3 in the hippocampus of SD rats was detected by Western blot. The activity of SOD was measured by the WST-1 cell proliferation and cytotoxicity method, the content of GSH was measured by the microplate method, and the content of MDA in the hippocampus of SD rats was measured by the TBA method. The behavioral changes of SD rats were detected by the open field test and water maze test. GraphPad Prism 9.0 was used for statistical analysis.One-way analysis of variance was used for comparisons among the three groups, and the LSD test was used for further pairwise comparisons, the t-test was used to compare the mean number of samples between the two groups. Results:(1) The mRNA and protein levels of TR1 in hippocampus of ovariectomized rats were lower than those of normal rats ( t=3.125, 4.402, both P<0.05). The mRNA and protein levels of TR1 in hippocampus of ovariectomized-TR1 rats were higher than those of ovariectomized rats ( t=4.945, 4.845, both P<0.05). (2) There were significant differences among the three groups in the escape latency in water maze test, the movement distance and the stay time in central area in the open field test ( F=44.73, 33.67, 6.51, all P<0.05), the movement distance in the open field test of ovariectomized rats was more than that of the normal group ((4 700±141) mm, (3 967±163) mm, P<0.05), the stay time in the central area was longer than that of the normal group ((87.33±3.93) s, (80.83±2.48) s, P<0.05), the movement distance ((4 267±150) mm) and the stay time in the central area ((82.17±3.43) s) of ovariectomized-TR1 group were lower than that of ovariectomized group ( P<0.05). In the water maze test, the escape latency of ovariectomized rats was longer than that of the normal group ((28.67±2.50) s, (19.50±2.59) s, P<0.05), and the escape latency in the ovariectomy-TR1 group((25.00±1.67) s) was shorter than that of ovariectomized TR1 group ( P<0.05). (3)There were significant differences in the levels of MDA, SOD and GSH in the hippocampus oxidative stress injury indexes among the three groups ( F=87.41, 91.38, 28.69, all P<0.01). The level of MDA in hippocampus of ovariectomized group was higher than that of normal group, and that in the ovariectomized-TR1 group was lower than that of ovariectomized rats group ( P<0.05). And what's more the levels of SOD and GSH in ovariectomized group were lower than those of normal group ( P<0.05), and the ovariectomized-TR1 group was higher than that of ovariectomized group ( P<0.05). (4) The results of Western blot and RT-PCR showed that the levels of p21 and p53 in hippocampal tissue of ovariectomized group were higher than those of normal group ( P<0.05), while the level of aging-related protein p21 and p53 in ovariectomized-TR1 group were significantly lower than those in ovariectomized group ( P<0.05). The level of apoptotic protein Caspase-3 in the hippocampus of ovariectomized rats was higher than that in the normal group ( P<0.05), while the level of Caspase-3 in ovariectomized-TR1 group was significantly lower than that in ovariectomized rats ( P<0.05). The level of anti-apoptotic protein Bcl-2 in hippocampus of ovariectomized group was lower than that of normal rats ( P<0.05), while the level of Bcl-2 in ovariectomized-TR1 group was significantly higher than that in ovariectomized rats ( P<0.05). Conclusion:Overexpression of TR1 can reduce apoptosis of hippocampal cells by regulating oxidative damage and reducing cell senescence.
ABSTRACT
The thioredoxin system is composed of thioredoxin (Trx), thioredoxin reductase (TR) and reduced nicotinamide adenine dinucleotide phosphate. Trx is an important antioxidant molecule that can resist cell death caused by various stresses and plays a prominent role in redox reactions. TR is a protein containing selenium (selenocysteine), mainly in three forms, i.e. TR1, TR2 and TR3. TR1 mainly distributed in the cytoplasm, TR2 mainly distributed in the mitochondria, and TR3 mainly distributed in the testes. TR can regulate cell growth and apoptosis. After the cell becomes cancerous, the expression of TR increases to promote cell growth and metastasis. Trx system is closely related to neurodegenerative diseases, parasitic infections, acquired immunodeficiency syndrome, rheumatoid arthritis, hypertension, myocarditis and so on. The Trx system can remove the reactive oxygen species (ROS) in the body, keep the inside and outside of the cell in a balanced state, and it interacts with the thioredoxin interacting protein (TXNIP), which plays an important role in the regulation of glucose metabolism and tumor treatment. The Trx system is an important target for drug treatment of many diseases. In this paper, the research progress of the thioredoxin system was reviewed.