Pretreatment of nucleus pulposus mesenchymal stem cells with appropriate concentration of H2O2 enhances their ability to treat intervertebral disc degeneration

Background

Nucleus pulposus mesenchymal stem cells (NPMSCs) transplantation is a promising treatment for intervertebral disc degeneration (IVDD). However, the transplanted NPMSCs exhibited weak cell proliferation, high cell apoptosis, and a low ability to resist the harsh microenvironment of the degenerated intervertebral disc. There is an urgent need to explore feasible methods to enhance the therapeutic efficacy of NPMSCs transplantation.

Objective

To identify the optimal concentration for NPMSCs pretreatment with hydrogen peroxide (H₂O₂) and explore the therapeutic efficacy of NPMSCs transplantation using H₂O₂ pretreatment in IVDD.

Methods

Rat NPMSCs were pretreated with different concentrations (range from 25 to 300 μM) of H₂O₂. The proliferation, reactive oxygen species (ROS) level, and apoptosis of NPMSCs were detected by cell counting kit-8 (CCK-8) assay, 5-ethynyl-2′-deoxyuridine (EdU) staining, and flow cytometry in vitro. The underlying signalling pathways were explored utilizing Western blotting. A rat needle puncture-stimulated IVDD model was established. X-ray, histological staining, and a multimode small animal live imaging system were used to evaluate the therapeutic effect of H₂O₂-pretreated NPMSCs in vivo.

Results

NPMSCs pretreated with 75 μM H₂O₂ demonstrated the strongest elevated cell proliferation by inhibiting the Hippo pathway (P < 0.01). Meanwhile, 75 μM H₂O₂-pretreated NPMSCs exhibited significantly enhanced antioxidative stress ability (P < 0.01), which is related to downregulated Brd4 and Keap1 and upregulated Nrf2. NPMSCs pretreated with 75 μM H₂O₂ also exhibited distinctly decreased apoptosis (P < 0.01). In vivo experiments verified that 75 μM H₂O₂-pretreated NPMSCs-transplanted rats exhibited an enhanced disc height index (DHI% = 90.00 ± 4.55, P < 0.01) and better histological morphology (histological score = 13.5 ± 0.5, P < 0.01), which means 75 μM H₂O₂-pretreated NPMSCs can better adapt to the environment of degenerative intervertebral discs and promote the repair of IVDD.

Conclusions

Pretreatment with 75 μM H₂O₂ was the optimal concentration to improve the proliferation, antioxidative stress, and antiapoptotic ability of transplanted NPMSCs, which is expected to provide a new feasible method to improve the stem cell therapy efficacy of IVDD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03031-7.

Iron Stable Isotopes in Bulk Soil and Sequential Extracted Fractions Trace Fe Redox Cycling in Paddy Soils

In paddy soils, iron (Fe) forms are highly influenced by the seasonal redox changes and leave detectable isotope signals because of fractionation between different Fe forms. Here, we present Fe concentrations and Fe isotope compositions (expressed as δ⁵⁶Fe values) in a paddy soil profile from Suzhou, China. Light Fe isotopes were enriched in two iron-accumulation layers (Br3 and G1) with high Fe concentrations. In particular, large shifts in both Fe concentrations and δ⁵⁶Fe values were found at the Br2 and Br3 boundaries, showing fast and efficient transformation between these horizons. With sequential extraction, we show that Fe isotopes in the short-range-ordered Fe minerals and crystalline Fe oxides were lighter than those in the residual silicate minerals. Iron enriched in light isotopes was leached from the Ap horizon and subsequently moved to Br horizon, quickly precipitating there as Fe oxides.

[Research advance in circular RNAs]

Circular RNAs (circRNAs) are a class of endogenous, covalently closed, single-stranded RNA without 3'-poly(A) and 5'-cap structures. CircRNAs are characterized by universality, diversity, stability and conservation, and have been found to regulate mammalian transcription and be translated into proteins. In this review, we summarized the biogenesis, classification, expression, distribution, biological functions and regulation of circRNAs. In addition, we discussed the association of circRNAs with diseases and the methods for identification and characterization of circRNAs. Finally, we speculated the application prospect and research direction of circRNAs.

Early intervention with gastrodin reduces striatal neurotoxicity in adult rats with experimentally‑induced diabetes mellitus

Glutamate-induced excitotoxicity in the striatum has an important role in neurodegenerative diseases. It has been reported that diabetes mellitus (DM) induces excitotoxicity in striatal neurons, although the underlying mechanism remains to be fully elucidated. The present study aimed to investigate the effect of gastrodin on DM-induced excitotoxicity in the striatal neurons of diabetic rats. Adult Sprague-Dawley rats were divided into control, diabetic, and gastrodin intervention groups. Diabetes in the rats was induced with a single intraperitoneal injection of streptozotocin (65 mg/kg). In the gastrodin groups, the rats were gavaged with 60 or 120 mg/kg/day gastrodin for 6 weeks, 3 weeks following the induction of diabetes. Pathological alterations in the striatum were assessed using hematoxylin and eosin (H&E) staining. The protein expression levels of phosphorylated (p)-extracellular signal-regulated kinase (ERK)1/2, p-mitogen-activated protein kinase kinase (MEK)1/2, tyrosine receptor kinase B (TrKB) and brain-derived neurotrophic factor (BDNF) in the striatal neurons were evaluated by western blotting and double immunofluorescence. Additionally, the extracellular levels of glutamate were measured by microanalysis followed by high-pressure-liquid-chromatography. In diabetic rats, striatal neuronal degeneration was evident following H&E staining, which revealed the common occurrence of pyknotic nuclei. This was coupled with an increase in glutamate levels in the striatal tissues. The protein expression levels of p-ERK1/2, p-MEK1/2, TrKB and BDNF in the striatal tissues were significantly increased in the diabetic rats compared with those in the normal rats. In the gastrodin groups, degeneration of the striatal neurons was ameliorated. Furthermore, the expression levels of glutamate, p-ERK1/2, p-MEK1/2, TrKB and BDNF in the striatal neurons were decreased. From these findings, it was concluded that reduced neurotoxicity in striatal neurons following treatment with gastrodin may be attributed to its suppressive effects on the expression of p-ERK1/2, p-MEK1/2, BDNF and TrKB.

Polymorphisms in the nuclear factor kappa B gene association with recurrent embryo implantation failure

Despite more than a century of intensive study, the mechanisms of successful pregnancy remain unclear. Recent research suggests that NF-κB (nuclear factor kappa B) plays an important role in embryo implantation. In the current study, we aimed to identify SNPs that contribute to genetic susceptibility for recurrent implantation failure (RIF). Thus, we examined the potential associations between RIF and ten SNPs (rs28362491, rs3774932, rs1598856, rs230528, rs230521, rs3774956, rs4648055, rs3774964, rs4648068, and rs3774968) of the NF-κB gene. Participants included 209 patients with RIF and 395 controls. Our results revealed that there were statistically significant differences observed in the allelic and genotypic frequencies of the rs28362491 promoter in the NF-κB gene. The frequency of the del/ del genotype was significantly higher in RIF patients than in healthy controls (P = 0.004). Compared with healthy controls, the RIF patients carried a higher frequency of the rs28362491 del allele (P = 0.010). Furthermore, strong linkage disequilibrium was observed in the three identified haplotype blocks (D' > 0.9). Particularly, in block 1 (rs230528-rs230521), the A-C haplotype occurred significantly more frequently (P = 0.029) in subjects with RIF (P = 0.0003). In contrast, the A-G haplotype occurred significantly less frequently (P = 0.008) in RIF subjects. These findings support an important role for G-712A polymorphisms of NF-κB in RIF, and may guide future studies that aim to characterize genetic risk factors for RIF.

Damaging effects of water-borne cadmium chloride on DNA of lung cells of immature mice

We investigated the effects of cadmium on lung cell DNA in immature mice. The mice were randomly divided into four groups: control group, low-dose group (1/100 LD(50)), middle-dose group (1/50 LD(50)), and high-dose group (1/25 LD(50)); they were supplied with cadmium chloride or control water for 40 days. Lung cells collected from sacrificed mice were used to evaluate the extent of DNA damage by comet assay. The ratio of tailing cells, DNA tail length, DNA comet length, DNA tail moment, DNA olive tail moment, and percentage of DNA in the comet tail were measured. The rate of tailing lung cells exposed to cadmium increased significantly; the low-concentration group had significantly (P < 0.05) higher rates, and the middle- and high-concentration groups had higher (P < 0.01) rates compared to the control. DNA tail length, DNA comet length, DNA tail moment, and DNA olive tail moment all increased with the increase in cadmium doses, but compared with those of the control group, no significant differences in low-dose group were found (P > 0.05), and the differences in middle- and high-dose groups were all highly significant (P < 0.01). The degree of DNA damage also increased with the increase of the cadmium concentrations. We conclude that cadmium significantly increases DNA damage in lung cells of immature mice in a dose-dependent manner.

[Proliferation of attenuated infections bursal disease virus(IBDV) on Vero cell on large scale]

Vero cell was selected as productive carrier in production of Attenuated IBDV. The optimal conditions in culturing IBDV in agitating bottle were figured out. After proliferation, supernatant was harvested in batch process under the condition of five-liter-agitated fermenter. The result shows it was successful to culture IBDV by this methodology.

[Carrier status of herpes viridae in pregnant women]

282 cervical swab specimens and serum samples collected from pregnant women were used for virological studies in order to investigate the carrier status in herpes viridae and antibody. Seven isolates were obtained with a positive rate of 2.48%. According to the characteristics of cytopathology effects on the diploid cells (2BS), pathogenicity in the hosts and electron micrographic findings, these 7 isolates belonged to herpes viridae. The results of neutralization test, enzyme linked immunosorbent assay blocking test and indirect immunofluorescence tests against HCMV-specific serum and standard HCMV AD-169, HSV-ISm44, HSV-IIG indicated that all these 7 viruses were HCMV. No other viral members of herpes viridae were detected in this study.

HLA restricted virus-specific cytotoxic T-lymphocyte responses to live and inactivated influenza vaccines

36 young adult volunteers were given either virus, or inactivated surface-antigen influenza vaccine, containing influenza A (H1N1) antigen. Their peripheral-blood lymphocytes were analysed to determine whether cytotoxic T lymphocytes (CTL) were induced by these vaccines. All three vaccines induced HLA-restricted T-lymphocyte responses specific for influenza A virus. This CTL response was found in 28 of 30 volunteers who showed antibody responses and in 3 of 6 who did not develop antibodies. Virus infected target cells showing certain HLA antigens (A1, A9, and B8) were less susceptible to lysis by HLA-matched cytotoxic T effector cells than target cells which matched effectors at other HLA loci.