The Journal of Toxicological Sciences
Online ISSN : 1880-3989
Print ISSN : 0388-1350
ISSN-L : 0388-1350
Volume 49, Issue 11
Displaying 1-4 of 4 articles from this issue
Original Article
  • Jiehuan Xu, Jianlin Chen, Dao Wang, Yaojun Li, Ping Lian, Xiaozhu Wu, ...
    2024 Volume 49 Issue 11 Pages 467-479
    Published: 2024
    Released on J-STAGE: November 01, 2024
    JOURNAL FREE ACCESS FULL-TEXT HTML

    Resistance to chemotherapeutic medicines complicates and eventually kills people with ovarian cancer. Nafamostat mesylate (NM) has been used as an adjuvant therapy to enhance chemotherapy sensitivity in several cancers. This study aimed to evaluate the effect of NM on ovarian cancer cells susceptible to carboplatin (CBP) and to determine the underlying mechanism involved. Herein, qRT-PCR, western blot, and IHC were used to analyze mRNA and protein expression. Cell viability and proliferation were measured using the MTT and colony formation assays. Cell migration and invasion were examined using the Transwell assay. Flow cytometry was employed to detect cell apoptosis. The interaction between zinc finger protein 24 (ZNF24) and wingless-type MMTV integration site family member 2b (WNT2B) was validated via the dual-luciferase reporter and Chromatin immunoprecipitation assays. A xenograft nude mouse model was used to assess the effect of NM on CBP sensitivity in vivo. Our results showed that NM intervention inhibited the viability, proliferation, migration, and invasion and facilitated the apoptosis of CBP-resistant ovarian cancer cells. Furthermore, NM sensitized ovarian cancer cells to CBP by upregulating ZNF24. ZNF24 inactivated Wnt/β-catenin signaling by inhibiting the transcription of WNT2B. Additionally, NM enhanced the inhibitory effect of CBP on tumor growth in vivo. Taken together, NM enhanced the CBP sensitivity of ovarian cancer cells by promoting the ZNF24-mediated inactivation of the WNT2B/Wnt/β-catenin axis. These findings suggest a viable treatment approach for improving CBP resistance in ovarian cancer.

Original Article
  • Xinyu Zou, Yousuke Watanabe, Shunsuke Ozawa, Yuri Ebizuka, Momoka Shob ...
    2024 Volume 49 Issue 11 Pages 481-495
    Published: 2024
    Released on J-STAGE: November 01, 2024
    JOURNAL FREE ACCESS FULL-TEXT HTML
    Supplementary material

    N-methyl-N-nitrosourea (MNU) exposure impairs hippocampal neurogenesis in rats. The present study investigated the gene expression profiles that were commonly up or downregulated across different brain substructures in response to repeated MNU administration in rats. Five-week-old rats were orally administered MNU at 0, 5, 15 mg/kg body weight/day for 28 days and subjected to gene expression microarray analysis in the hippocampal dentate gyrus, corpus callosum, cerebral cortex and cerebellar vermis. MNU at 15 mg/kg revealed multiple functional clusters of upregulated genes related to immune and inflammatory responses in all brain regions, and also clusters of up or downregulated genes related to regulation of apoptotic process in several regions. Specifically, the upregulated genes commonly found in all four regions were enriched in clusters of “immune response” and/or “inflammatory response” (Cd74, Ccl3, Fcgr3a, Serping1, Lgals3, Fcgr2b, Hcst, Kcnn4, Tnf, Gpr18, Tyrobp and Cyba) and “metal-binding proteins” (Mt1, Mt2A and Apobec1). Meanwhile, downregulated genes common to all four regions (Bmp4, Vcan and Fhit) were included in clusters of “cell proliferation”, “glial cell migration” and “nucleotide metabolism”. Immunohistochemical analysis of representative gene products revealed that in all brain regions examined, MNU treatment increased metallothionein-I/II + cells and galectin-3+ cells co-expressing Iba1, and also increased Iba1+ and CD68+ cells. These results suggest that repeated MNU administration in rats causes neuroinflammation and oxidative stress accompanied by apoptosis of neural cell components in the brain, as well as concurrent anti-inflammatory responses for neuroprotection from MNU exposure, involving activation of microglia producing metallothionein-I/II and galectin-3 on these responses.

Original Article
  • Hongbin Wang, Wei Li
    2024 Volume 49 Issue 11 Pages 497-507
    Published: 2024
    Released on J-STAGE: November 01, 2024
    JOURNAL FREE ACCESS FULL-TEXT HTML
    Supplementary material

    Diabetic nephropathy (DN) is a severe microvascular complication of diabetes, of which progression is related to high glucose (HG)-induced oxidative stress in renal mesangial cells. Our study aims to explore the antioxidant activity and the underlying mechanism of Puerarin (Pu) in renal mesangial cells exposed to HG. After the cells finished different treatments, DCFH-DA was used to detect the generation of ROS while the expression of AGE, MDA, SOD, and GSH-PX was measured by the ELISA and corresponding kits. The cell morphology was captured by optical microscopy. The mRNA expressions of RAGE, PKCα, PKCβ, PKCγ, and NOX4 were calculated by RT-PCR assays, while the protein expressions of RAGE, NOX4, and PKCβ were quantified via western blotting. Compared with the normal glucose (NG) group, the ROS level, SOD activity, and GSH-PX expression were markedly reduced in the HG group while the MDA expression was increased in the HG group. Then, Pu treatment was proved to significantly prevent the HG-induced up-regulation of ROS level, MDA expression, and down-regulation of SOD activity and GSH-PX expression. Besides, Pu treatment can notably inhibit the AGE expression and reverse the increased RAGE, PKCβ, and NOX4 expressions by HG environment at both RNA and protein levels. Moreover, the antioxidant effect of Pu against access glucose could not be observed in PKCβ knockdown cells. Pu can alleviate the HG-induced oxidative stress via the RAGE/PKC/NOX4 axis in renal mesangial cells, which innovatively suggests the therapeutic potential of Pu for DN treatment.

Original Article
  • Hidenori Suto, Keiko Ogata, Kenta Minami, Akira Sato, Naruto Tomiyama, ...
    2024 Volume 49 Issue 11 Pages 509-529
    Published: 2024
    Released on J-STAGE: November 01, 2024
    JOURNAL FREE ACCESS FULL-TEXT HTML
    Supplementary material

    We propose a modified Comparative Thyroid Assay (CTA, USEPA) utilizing a smaller number of Sprague-Dawley rats (N=10/group) that assesses brain thyroid hormone (TH) concentrations and periventricular heterotopia while maintaining assay sensitivity. Our recent findings demonstrated that a prenatal test cohort of the modified CTA detected a dose-dependent decrease in maternal serum T3 (up to -26%) and T4 (up to -44%) with sodium phenobarbital (NaPB) exposure at 1000 ppm and 1500 ppm, equivalent to intakes of 60 and 84 mg/kg/day, respectively. On gestation day (GD) 20, fetuses exhibited reduced serum (-26%) and brain (-29%) TH concentrations, although these reductions were not dose dependent. The present study expanded the treatment in a postnatal test cohort, with maternal exposure to NaPB (81-93 mg/kg/day) from GD6 to lactation day (LD) 21. We assessed serum and brain TH concentrations, and periventricular heterotopia in pups on postnatal days (PND) 4, 21, and 28. While LD21 dams showed significant reductions in serum T3 (up to -34%) and T4 (up to -54%), the pups did not exhibit significant TH suppression or periventricular heterotopia at any test point. Instead, a compensatory increase in T4 was observed in serum and brain of PND21 pups. The present study confirmed that perinatal maternal exposure to high doses of NaPB leads to a moderate decrease in maternal TH concentrations; however, the exposure of maternal rats to a similar dose of NaPB did not significantly reduce serum or brain TH concentrations in their postnatal offspring.

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