Biomechanical evaluation on a new type of vertebral titanium porous mini-plate and mechanical comparison between cervical open-door laminoplasty and laminectomy: a finite element analysis

Objective: Compare the spine's stability after laminectomy (LN) and laminoplasty (LP) for two posterior surgeries. Simultaneously, design a new vertebral titanium porous mini plate (TPMP) to achieve firm fixation of the open-door vertebral LP fully. The objective is to enhance the fixation stability, effectively prevent the possibility of "re-closure," and may facilitate bone healing. Methods: TPMP was designed by incorporating a fusion body and porous structures, and a three-dimensional finite element cervical model of C2-T1 was constructed and validated. Load LN and LP finite element models, respectively, and analyze and simulate the detailed processes of the two surgeries. It was simultaneously implanting the TPMP into LP to evaluate its biomechanical properties. Results: We find that the range of motion (ROM) of C4-C5 after LN surgery was greater than that of LP implanted with different plates alone. Furthermore, flexion-extension, lateral bending, and axial rotation reflect this change. More noteworthy is that LN has a much larger ROM on C2-C3 in axial rotation. The ROM of LP implanted with two different plates is similar. There is almost no difference in facet joint stress in lateral bending. The facet joint stress of LN is smaller on C2-C3 and C4-C5, and larger more prominent on C5-C6 in the flexion-extension. Regarding intervertebral disc pressure (IDP), there is little difference between different surgeries except for the LN on C2-C3 in axial rotation. The plate displacement specificity does not significantly differ from LP with vertebral titanium mini-plate (TMP) and LP with TPMP after surgery. The stress of LP with TPMP is larger in C4-C5, C5-C6. Moreover, LP with TMP shows greater stress in the C3-C4 during flexion-extension and lateral bending. Conclusion: LP may have better postoperative stability when posterior approach surgery is used to treat CSM; at the same time, the new type of vertebral titanium mini-plate can achieve almost the same effect as the traditional titanium mini-plate after surgery for LP. In addition, it has specific potential due to the porous structure promoting bone fusion.

Amonafide Induces HUVEC Senescence by Inhibiting Autophagy

BACKGROUND

Amonafide (Amo), due to hematotoxicity and digestive tract symptoms, the clinical application of which is limited. Several studies have reported that chemotherapy side effects are closely related to cellular senescence accumulation. Our study aims to examine whether amonafide causes senescence in human umbilical vein endothelial cell (HUVEC) lines and investigate its mechanisms associated with senescence.

METHODS

The experiments of expression of genes and proteins associated with aging were carried out with HUVEC cell lines. The experiments were divided into a control group and an amonafide group with different days. The HUVEC senescence cells were detected by SA-β-Gal staining, Western blotting detected the protein levels of p16, p53, AMPK (Adenosine 5'-Monophosphate (AMP)-Activated Protein Kinase), mTOR (mechanistic Target of Rapamycin), p62, and LC3 (microtubule-associated protein1 light chain 3, MAP1LC3). Fluorescence detected the expression of mRFP (monomeric Red Fluorescent Protein)-GFP (Green Fluorescent Protein)-LC3 and LC3 puncta of HUVEC cells. RT-qPCR (Real-Time Quantitative Polymerase Chain Reaction) tested the expressions of p53, p21, IL (Interleukin)-1β, IL-6 (Interleukin-6), IL-8 (Interleukin-8), and MCP-1 (Monocyte Chemoattractant Protein-1). CCK-8 (Cell Counting Kit-8) assessed the HUVEC cell viability.

RESULTS

Here, we reported that amonafide resulted in an increased proportion of SA-β-Gal positive cells, high expression of aging-related proteins (p53 p < 0.05; p16 p < 0.05), and aging-related genes (p53 p < 0.05; p21 p < 0.05; IL-1β p < 0.05; IL-6 p < 0.05; IL-8 p < 0.05; MCP-1 p < 0.05) on the 3rd day. Mechanistically, amonafide could cause an increase in the levels of the mTOR (p < 0.05) on days 1 and 3, and p62 protein (p < 0.05) on day 1, and a decline in LC3II (microtubule-associated protein1 light chain 3Ⅱ)/LC3I levels (p < 0.05) on day 3, which is associated with the regulation of senescence. Additionally, the viability of HUVECs (human umbilical vein endothelial cells) was significantly inhibited by amonafide starting with a concentration of 0.8 μm (p < 0.05).

CONCLUSIONS

We first discovered that amonafide caused normal cellular senescence in our experiments. Amonafide-induced cellular aging by inhibiting autophagy and activating the mTOR pathway. The findings may offer new strategies for managing adverse reactions to amonafide.

Correlation between PRDX2 and spermatogenesis under oxidative stress

BACKGROUND

Obesity is one of the world's diseases that endanger human health, causing systemic inflammation caused by excessive reactive oxygen damage. An increase in the proportion of obese people with reduced sperm motility has been reported. But the mechanism behind it remains unclear. Peroxiredoxin 2 (PRDX2) is a member of the peroxidase family that effectively removes hydrogen peroxide. This study is to clarify the expression of PRDX2 in the testes of obese mice and lay a foundation for further exploration of the regulatory and protective effects of PRDX2 on spermatogenesis.

METHOD

A model of high-fat-induced obesity in animals was constructed, and the expression of PRDX2 in the testes of the two groups was detected by immunohistochemistry, western blotting, immunofluorescence and other techniques. Hydrogen peroxide (H₂O₂) and cholesterol were co-cultured in testicular support cells for 48 h to observe the expression of PRDX2.

RESULT

PRDX2 expression was reduced in the testes of the obese group, and immunohistochemistry showed that it was mainly localized to supporting cells. H₂O₂ inhibits the expression of PRDX2 in Sertoli cells, and high cholesterol upregulates the expression of PRDX2 in Sertoli cells.

CONCLUSION

PRDX2 has some antioxidant properties against changes in the testicular environment caused by HFD. And under short-term oxidative stress to enhance its antioxidant capacity. PRDX2 may be involved in maintaining the oxidative balance of the spermatogenesis environment.

Anti-inflammation and anti-aging mechanisms of mercaptopurine in vivo and in vitro

Skin is the biggest organ of the human body, which easily gets irritated by exposure to the sun. Skin photoaging and acute photodamage are caused by intense UV-B radiation. Therefore, it is imperative to find new compounds to prevent skin damage and aging. Mercaptopurine is an immunologic agent commonly used for treating Acute lymphoblastic leukemia and inflammatory bowel disease. The beneficial effects of mercaptopurine on the skin have not been reported, and its intrinsic mechanism of action is unclear. Therefore, this study was to explore mercaptopurine when exposed to UV-B radiation in HacaT cells and C57BL6 mice aging and damage effects. The model of in vivo UV-B-induced skin damage and skin photoaging was established, and the impact of mercaptopurine on cell and animal skin was studied. The study found that mercaptopurine, on the one hand, inhibits cellular and animal senescence. On the other, it inhibits the expression of mitogen-activated protein kinase (MAPK) and the nuclear factor κB (NF-κB), which are important signaling molecules in the early UV-B reaction signaling pathway. In addition, mercaptopurine downregulates matrix metalloproteinase expression, increases collagen fiber content, and facilitates collagen synthesis. Treatment with mercaptopurine also inhibits the expression of inflammatory factors and reduces inflammatory cell infiltration of the skin. In conclusion, our study elucidates mercaptopurine's anti-photoaging and anti-inflammatory activity in cellular and animal models.

Neuronal activity in the dorsal dentate gyrus during extinction regulates fear memory extinction and renewal

Memory extinction and renewal are major factors that limits the efficacy of exposure therapy. The dorsal dentate gyrus (dDG) plays a crucial role in spatial memory, and epigenetic modifications in the dDG play an important role in fear memory renewal. However, whether dDG activity regulates fear memory extinction and renewal remains unclear. In this study, we showed that an extinction procedure that prevents fear memory renewal (extinction within the reconsolidation window) leads to increased c-fos expression in the dDG. Chemicogenetic activation of dDG excitatory neurons during extinction training elevated fear memory extinction and prevented renewal, whereas inhibition of dDG excitatory neurons inhibited fear memory extinction. We also demonstrated that inhibiting fear engram cells (neurons active during fear acquisition) during extinction training inhibits fear memory extinction. Therefore, dDG activity during fear extinction plays an important role in fear memory extinction and renewal.

Maternal separation affects Anxiety like behavior begin in adolescence continue through adulthood and related to Dnmt3a expression

Early life stress, including maternal separation, is among one of the main causes of anxiety in adolescents. DNA methyltransferase 3A (Dnmt3a) is a key molecule that regulates DNA methylation and is found to be associated with anxiety-like behavior. It is not clear whether maternal separation affects anxiety levels in mice at different developmental stages, or whether Dnmt3a plays a role in this process. Here, by using open field test to exploring the effect of maternal separation on anxiety-like behavior in mice of different age, it was found that maternal separation could successfully induce anxiety-like behavior in adolescent mice, and which continued through adulthood. By using western blot, we found the levels of Dnmt3a in the hippocampus and cortex have shown different trends in maternal separation mice on P17. Further, by using immunostaining, we have found that the expression levels of Dnmt3a in the cortex and hippocampus were significantly different, and decreased to varying degrees with the age of mice, which being the reason for different trends. Our results provide an experimental basis for further development of anxiety/depression treatment programs more suitable for adolescence.