Compound probiotics regulate the NRF2 antioxidant pathway to inhibit aflatoxin B1-induced autophagy in mouse Sertoli TM4 cells.

This study investigated the effects of compound probiotics (CP) on AFB1-induced cytotoxicity in Sertoli TM4 cells. The L9 (3 × 3) orthogonal test was conducted to determine the optimal CP required for high AFB1 degradation in the artificial gastrointestinal fluid in vitro. The maximal AFB1 degradation rate was 40.55 % (P < 0.05) when the final viable count was 1.0 × 105 CFU/mL for Bacillus subtilis, Lactobacillus casein, and Saccharomyces cerevisiae. The effects of CP and the CP supernatant (CPS) on TM4 cell viability were evaluated to achieve the optimal protective conditions. When CPS4 (corresponding to CP viable counts of 1.0 × 104 CFU/mL) was added to the TM4 cells for 24 h, the cell viability reached 108.86 % (P < 0.05). AFB1 reduced TM4 cell viability in a concentration- and time-dependent manner at an AFB1 concentration ranging from 0 to 1.5 µM after 48-h AFB1 exposure. The optimal AFB1 concentration/times for low- and high damage models were 0.5 and 1.25 µM both for 24 h, which decreased viability to 76.04 % and 65.35 %, respectively. however, CPS4 added to low- and high-damage models increased the cell viability to 97.43 % and 75.12 %, respectively (P < 0.05). Transcriptome sequencing was performed based on the following designed groups: the control, 0.5 µM AFB1, 1.25 µM AFB1, CPS4, and CPS4+0.5 µM AFB1. The Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis was further performed to identify significantly enriched signaling pathways, which were subsequently verified. It was shown that AFB1 induced apoptosis by blocking the PI3K-AKT-mTOR pathway and upregulating autophagy proteins such as LC3B, Beclin1, and ATG5 while inhibiting autophagic flux. CPS4 promoted AFB1 degradation, activated the p62-NRF2 antioxidant, and inhibited ROS/TRPML1 pathways, thereby reducing ROS production and inflammation and ultimately alleviating AFB1-induced autophagy and apoptosis. These findings supports the potential of probiotics to protect the male reproductive system from toxin damage.

Assessment of the toxicity of different antiretroviral drugs and their combinations on Sertoli and Leydig cells.

The human immunodeficiency virus continues to pose a significant global public health challenge, affecting millions of individuals. The current treatment strategy has incorporated the utilization of combinations of antiretroviral drugs. The administration of these drugs is associated with many deleterious consequences on several physiological systems, notably the reproductive system. This study aimed to assess the toxic effects of abacavir sulfate, ritonavir, nevirapine, and zidovudine, as well as their combinations, on TM3 Leydig and TM4 Sertoli cells. The cell viability was gauged using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) and neutral red uptake (NRU) assays. Reactive oxygen species (ROS) production was assessed via the 2',7'-dichlorofluorescein diacetate (DCFDA) test, and DNA damage was determined using the comet assay. Results indicated cytotoxic effects at low drug concentrations, both individually and combined. The administration of drugs, individually and in combination, resulted in the production of ROS and caused damage to the DNA at the tested concentrations. In conclusion, the results of this study suggest that the administration of antiretroviral drugs can lead to testicular toxicity by promoting the generation of ROS and DNA damage. Furthermore, it should be noted that the toxicity of antiretroviral drug combinations was shown to be higher compared to that of individual drugs.

Cadmium exposure induces pyroptosis of TM4 cells through oxidative stress damage and inflammasome activation.

Cadmium (Cd) is a harmful metal that seriously affects the male reproductive system, but the mechanism of how Cd exposure damages Sertoli cells is not fully understood. This study used TM4 cells to explore the mechanism of Cd damage to Sertoli cells. We found that Cd was concentration- and time-dependent on TM4 cell viability. Cd exposure increased intracellular reactive oxygen species (ROS) levels, lactate dehydrogenase (LDH), and Interleukin-1ß (IL-1ß) release in TM4 cells, decreased mitochondrial function, and increased pyroptosis. N-acetylcysteine (NAC), MCC950 and BAY 11-7082 (BAY) alleviate the release of IL-1ß and LDH induced by Cd. NAC reduced Cd induced increases in ROS, NLRP3, Caspase-1, Heme oxygenase-1(HO-1), superoxide dismutase (SOD2), and increased mitochondrial function. The activation of GSDMD is the main causes of pyroptosis, and NAC significantly inhibit its activation and formation. Our results suggest that Cd exposure induces a toxic mechanism of GSDMD-mediated pyroptosis in TM4 cells by increasing ROS levels and activating the inflammasome.

Titanium dioxide nanoparticles induce apoptosis through ROS-Ca2+-p38/AKT/mTOR pathway in TM4 cells.

Titanium dioxide nanoparticles (TiO2 NPs) can cause apoptosis in TM4 cells; however, the underlying mechanism has not been entirely elucidated. The purpose of this study was to investigate the effects of TiO2 NPs on ROS, Ca2+ level, p38/AKT/mTOR pathway, and apoptosis in TM4 cells and to evaluate the role of Ca2+ in p38/AKT/mTOR pathway and apoptosis. After exposure to different concentrations (0, 50, 100, 150, and 200 µg/mL) of TiO2 NPs for 24 h, cell viability, ROS, Ca2+ level, Ca2+-ATPase activity, p38/AKT/mTOR pathway-related proteins, apoptosis rate, and apoptosis-related proteins (Bax, Bcl-2, Caspase 3, Caspase 9, and p53) were detected. The ROS scavenger NAC was used to determine the effect of ROS on Ca2+ level. The Ca2+ chelator BAPTA-AM was used to evaluate the role of Ca2+ in p38/AKT/mTOR pathway and apoptosis. TiO2 NPs significantly inhibited cell viability, increased ROS level, and elevated Ca2+ level while suppressing Ca2+-ATPase activity. TiO2 NPs regulated the p38/AKT/mTOR pathway via increasing p-p38 level and decreasing p-AKT and p-mTOR levels. TiO2 NPs significantly enhanced the apoptosis. NAC attenuated Ca2+ overload and reduction in Ca2+-ATPase activity caused by TiO2 NPs. BAPTA-AM alleviated TiO2 NPs-induced abnormal expression of p38/AKT/mTOR pathway-related proteins. BAPTA-AM assuaged the apoptosis caused by TiO2 NPs. Altogether, this study revealed that TiO2 NPs elevated intracellular Ca2+ level through ROS accumulation. Subsequently, the heightened intracellular Ca2+ level was observed to exert regulation over the p38/AKT/mTOR pathway, ultimately culminating in apoptosis. These results provides a complementary understanding to the mechanism of TiO2 NPs-induced apoptosis in TM4 cells.

[KEAP1/PGAM5/AIFM1 mediated oxeiptosis pathway in TDCIPP-induced reduction of TM4 cell viability].

OBJECTIVE: To investigate the toxic effects and potential mechanisms of tri(1, 3-dichloro-2-propyl) phosphate(TDCIPP) exposure on the mouse testicular supporting cell line(TM4 cells). METHODS: TM4 cells were treated with different concentrations of TDCIPP(0, 12.5, 25 and 50 µmol/L), or 50 µmol/L TDCIPP combined with antioxidant N-acetylcysteine(NAC) for 24 h. Cell viability was assessed using the CCK8 assay, intracellular ROS levels were detected using the DCFH-DA probe, and the protein levels of oxeiptosis-related proteins, such as KEAP1, PGAM5, AIFM1 and phosphorylated AIFM1(p-AIFM1), were detected using Western blot. RESULTS: TDCIPP dose-dependently reduced TM4 cell viability(P<0.05). ROS levels in TM4 cells treated with 12.5, 25 and 50 µmol/L TDCIPP were 9.44±1.42, 17.25±1.81 and 18.38±2.66, respectively, significantly higher than the control group's 5.08±0.90(P<0.05). ROS levels in the 5 mmol/L NAC+50 µmol/L TDCIPP group were 14.70±0.50, significantly lower than the corresponding TDCIPP group's 26.44±0.73(P<0.05). The activity of TM4 cells in KEAP1siRNA+TDCIPP group and PGAM5siRNA+TDCIPP group were 77.00±1.73 and 76.67±1.53, respectively, significantly higher than TDCIPP group 68.67±1.53(P<0.05). The relative expression of KEAP1 protein in TM4 cells treated with 25 and 50 µmol/L TDCIPP were 0.77±0.04 and 0.82±0.02, respectively, significantly higher than the control group's 0.57±0.01(P<0.05). The relative expression of PGAM5 protein in TDCIPP-treated TM4 cells were 1.17±0.04, 1.38±0.03 and 1.41±0.03, respectively, significantly higher than the control group's 0.81±0.02(P<0.05). The relative expression of AIFM1 protein were 0.42±0.01, 0.63±0.01 and 0.68±0.02, respectively, significantly higher than the control group's 0.34±0.02(P<0.05). The relative expression of p-AIFM1 protein were 1.73±0.02, 1.52±0.02 and 0.73±0.01, respectively, significantly lower than the control group's 2.25±0.02(P<0.05). In the 5 mmol/L NAC+50 µmol/L TDCIPP group, the relative expression of KEAP1, PGAM5 and AIFM1 proteins in TM4 cells were 0.61±0.01, 0.58±0.01 and 0.48±0.03, respectively, significantly lower than the TDCIPP group's 0.86±0.12(P<0.05), 0.74±0.02(P<0.05) and 0.92±0.01(P<0.05). The relative expression of p-AIFM1 protein in the 5 mmol/L NAC+50 µmol/L TDCIPP group was 0.45±0.11, significantly higher than the TDCIPP group's 0.23±0.01(P<0.05). CONCLUSION: The reduction of TM4 cell viability induced by TDCIPP may be related to ROS-mediated regulation of the KEAP1/PGAM5/AIFM1 pathway, leading to oxeiptosis.

Role and possible mechanism of estrogen receptor α down-regulation leading to damage of TM4 Sertoli cell connectivity in mice / 中国药理学通报

Aim To investigate the role of autophagy in the dysfunction of testicular TM4 cell junction induced by ERα down-regulation. Methods TM4 cells were treated with different concentrations of E R a inhibitor ICI182780 (ICI), and the proliferative activity of TM4 cells was detected by CCK-8 method. The number and morphological changes of TM4 cells were observed by light microscope. The levels of E R a, junction function related proteins and autophagy marker proteins were detected by Western blot. The expression and localization of Cx43 were detected by immunofluorescence staining. The cells were treated with chloroquine (CQ) and ICI for 24 h. The expression levels of autophagy and junction function related proteins were detected by Western blot. Results When ICI concentration was 50 nmol • L ~ or above, the cell viability decreased significantly. The increase of cell vacuoles in ICI group was observed by light microscope. Compared with normal control group, the protein expression levels of E R a, ZO-1, occludin, claudin-11, p-catenin and Cx43 in ICI groups significantly dropped, while the expression levels of N-cadherin and E-cadherin had no significant changes; LC3 II significantly rose, while p62 expression significantly fell. The results of immunofluorescence showed that the fluorescence expression of Cx43 in ICI group decreased significantly, but the position of CX43 did not change significantly. Compared with ICI group, the expression levels of LC3 II, p62, Cx43, ZO-1 and β-Catenin significantly increased. Conclusions The down-regulation of E R a leads to damage of TM4 cell junction function, which may be related to the activation of autophagy.

Effects of flurochloridone on apoptosis and Nrf2/HO-1 and NFκB signaling pathways in mouse testis and TM4 cells / 环境与职业医学

Background Flurochloridone (FLC) is toxic to male reproduction and can induce apoptosis of testicular tissue and supporting cells under oxidative stress. Of particular concern is whether nuclear factor-erythrocyte 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling pathway and nuclear factor kappa B (NFκB) signaling pathway participate this process. Objective To observe apoptosis of testicular tissue and sertoli TM4 cells and alterations of Nrf2/HO-1 and NFκB signaling pathways in mice treated with FLC in vivo/in vitro. Methods (1) Animal experiment. Testis samples were harvested from male C57BL/6 mice after 28-day FLC (0, 3, 15, 75, and 375 mg·kg−1 per day) exposure via oral route. Malondialdehyde (MDA) and superoxide dismutase (SOD) in homogenate of testicular tissue were measured by colorimetry. Apoptosis of testicular tissue was evaluated by TUNEL staining. Expression and distribution of Nrf2 and NFκB were detected by immunohistochemistry. Protein expression levels of Nrf2, HO-1, NAD(P)H: quinone oxidoreductase 1 (NQO1), NFκB, inhibitor of nuclear factor kappa-B kinase subunit beta (IKKβ), and phosphorylated recombinant inhibitory subunit of nuclear factor kappa-B alpha (P-IκBα) in testicular tissue homogenate were determined by Western blotting. (2) Cell experiment. TM4 cell lines were treated with 40, 80, 120, 160, and 200 μmol·L−1 FLC for 6 h, and cell viability was detected by CCK-8. After 6 h exposure to 40, 80, and 160 μmol·L−1 FLC, the apoptosis rate was detected by flow cytometry, and the protein expression levels of Nrf2, HO-1, NQO1, NFκB, IKKβ, and IκBα were detected by Western blotting. Results (1) Animal experiment. Apoptosis occurred in the interstitial and basal parts of spermatogenic tubules in male C57BL/6 mice after 28 days of oral FLC exposure. Compared with the control group, the MDA level in testicular tissue of the 375 mg·kg−1 FLC-treated group was significantly increased (P<0.05), and the SOD activity was significantly decreased (P<0.05). After 375 mg·kg−1 FLC exposure, apoptosis occurred in the interstitial and basal parts of spermatogenic tubules. The results of immunohistochemistry showed the expression of Nrf2 and NFκB in the interstitium and basal part of spermatogenic tubules of the treated groups. Compared with the control group, the protein levels of Nrf2, NQO1, P-IκBα, NFκB, and IKKβ in the 15, 75, and 375 mg·kg-1 groups were significantly increased (P<0.001), and the HO-1 protein level was significantly increased in the 375 mg·kg−1 group (P<0.001). (2) Cell experiment. Compared with the control group, the TM4 cell viabilities in the 40, 80, 120, 160, and 200 μmol·L−1 FLC-treated groups significantly decreased (P<0.01). The apoptosis rates were significantly increased (P<0.05), and the apoptosis rates increased from 5.7% in the control group to 7.4%, 9.4%, and 11.7% in the 40, 80, and 160 μmol·L−1, respectively. The Nrf2 protein level in the 40 μmol·L−1 group was significantly increased (P<0.01), while the levels significantly decreased in the 80 and 160 μmol·L−1 groups (P<0.01). The HO-1 protein levels in the 40, 80, and 160 μmol·L−1 groups were significantly increased (P<0.01). The level of NQO1 protein in the 40 μmol·L−1 group was significantly increased (P<0.01). The NFκB protein levels were significantly increased in the 80 and 160 μmol·L−1 groups (P<0.001). The IκBα protein levels were significantly decreased in all treated groups (P<0.001). The IKKβ protein had no significant change. Conclusion FLC induces testicular tissue apoptosis, and the process affects Nrf2/HO-1 signaling pathway and NFκB signaling pathway. The in vitro study confirms that FLC could induce apoptosis of TM4 cells and activate Nrf2/HO-1 and NFκB signaling pathways.