Aged garlic extract protects against methotrexate-induced apoptotic cell injury of IEC-6 cells

Methotrexate upregulates circadian transcriptional factors PAR bZIP to induce apoptosis on rheumatoid arthritis synovial fibroblasts

Background

Effects of methotrexate (MTX) on the proliferation of rheumatoid arthritis (RA) synovial fibroblasts are incompletely understood. We explored actions of MTX in view of circadian transcriptions of synovial fibroblasts.

Methods

Under treatment with MTX, expression of core circadian clock genes, circadian transcriptional factor proline and acidic amino acid-rich basic leucine zipper (PAR bZIP), and proapoptotic molecule Bcl-2 interacting killer (Bik) was examined by real-time polymerase chain reaction. Protein expression of circadian clock gene PERIOD2 (PER2) and CYTOCHROME C was also examined by western blotting and ELISA. Promoter activities of Per2 and Bik were measured by Luciferase assay. Expression of PER2, BIK, and CYTOCHROME C and morphological changes of the nucleus were observed by fluorescent immunostaining. Synovial fibroblasts were transfected with Per2/Bik small interfering RNA, and successively treated with MTX to determine cell viabilities. Finally, synovial fibroblasts were treated with MTX according to the oscillation of Per2/Bik expression.

Results

MTX (10 nM) significantly decreased cell viabilities, but increased messenger RNA expression of Per2, Bik, and PAR ZIP including D site of the albumin promoter binding protein (Dbp), hepatic leukemia factor (Hlf), and thyrotroph embryonic factor (Tef). MTX also increased protein expression of PER2 and CYTOCHROME C, and promoter activities of Per2 and Bik via D-box. Under fluorescent observations, expression of PER2, BIK, and CYTOCHROME C was increased in apoptotic cells. Cytotoxicity of MTX was attenuated by silencing of Per2 and/or Bik, and revealed that MTX was significantly effective in situations where Per2/Bik expression was high.

Conclusions

We present here novel unique action of MTX on synovial fibroblasts that upregulates PAR bZIP to transcribe Per2 and Bik, resulting in apoptosis induction. MTX is important in modulating circadian environments to understand a new aspect of pathogenesis of RA.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1552-9) contains supplementary material, which is available to authorized users.

Screening of cytoprotectors against methotrexate-induced cytogenotoxicity from bioactive phytochemicals

As a well known anti-neoplastic drug, the cytogenotoxicity of methotrexate (MTX) has received more attention in recent years. To develop a new cytoprotector to reduce the risk of second cancers caused by methotrexate, an umu test combined with a micronucleus assay was employed to estimate the cytoprotective effects of ten kinds of bioactive phytochemicals and their combinations. The results showed that allicin, proanthocyanidins, polyphenols, eleutherosides and isoflavones had higher antimutagenic activities than other phytochemicals. At the highest dose tested, the MTX genetoxicity was suppressed by 34.03%∼67.12%. Of all the bioactive phytochemical combinations, the combination of grape seed proanthocyanidins and eleutherosides from Siberian ginseng as well as green tea polyphenols and eleutherosides exhibited stronger antimutagenic effects; the inhibition rate of methotrexate-induced genotoxicity separately reached 74.7 ± 6.5% and 71.8 ± 4.7%. Pretreatment of Kunming mice with phytochemical combinations revealed an obvious reduction in micronucleus and sperm abnormality rates following exposure to MTX (p < 0.01). Moreover, significant increases in thymus and spleen indices were observed in cytoprotector candidates in treated groups. The results indicated that bioactive phytochemicals combinations had the potential to be used as new cytoprotectors.

Escherichia coli Nissle 1917-derived factors reduce cell death and late apoptosis and increase transepithelial electrical resistance in a model of 5-fluorouracil-induced intestinal epithelial cell damage

We evaluated the capacity for supernatants (SNs) derived from Escherichia coli Nissle 1917 (EcN), cultured under different growth conditions, to prevent 5-fluorouracil (5-FU)-induced intestinal epithelial cell damage. EcN was cultured in: Luria Bertani (LB) broth, tryptone soya broth (TSB), de Man Rogosa Sharpe (MRS) broth, and M17 broth supplemented with 10% (v/v) lactose solution (M17). Intestinal epithelial cells (IEC-6) were treated with the following EcN SNs: LB(+), TSB(+), MRS(+), and M17(+) in the presence and absence of 5-FU (1.5 or 5 μM). Cell viability, apoptotic activity and cell monolayer permeability were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), flow cytometry, and transepithelial electrical resistance (TER) assays, respectively. 5-FU significantly reduced cell viability (P<0.05) at both 24 and 48 h. However, only EcN SN produced from LB and M17 growth media significantly decreased cell death induced by 5-FU (by approximately 10% after 24 and 48 h; and 10% after 24 h, respectively [P<0.05]). When measured by flow cytometry all EcN SNs in the presence of 5-FU increased the proportion of viable cells (by 3-5% for 24 h, 3-7% for 48 h, P<0.05) and reduced late-apoptotic cells after 24 and 48 h, compared with 5-FU control. Moreover, all EcN SNs significantly reduced the disruption of IEC-6 cell barrier function induced by 5-FU by 7-10% (P<0.05), compared with DMEM control. We conclude that EcN derived factors could potentially reduce the severity of intestinal mucositis.

Lutein protects against methotrexate-induced and reactive oxygen species-mediated apoptotic cell injury of IEC-6 cells

Purpose

High-dose chemotherapy using methotrexate (MTX) frequently induces side effects such as mucositis that leads to intestinal damage and diarrhea. Several natural compounds have been demonstrated of their effectiveness in protecting intestinal epithelial cells from these adverse effects. In this paper, we investigated the protection mechanism of lutein against MTX-induced damage in IEC-6 cells originating from the rat jejunum crypt.

Methods

The cell viability, induced-apoptosis, reactive oxygen species (ROS) generation, and mitochondrial membrane potential in IEC-6 cells under MTX treatment were examined in the presence or absence of lutein. Expression level of Bcl2, Bad and ROS scavenging enzymes (including SOD, catalase and Prdx1) were detected by quantitative RT-PCR.

Results

The cell viability of IEC-6 cells exposed to MTX was decreased in a dose- and time-dependent manner. MTX induces mitochondrial membrane potential loss, ROS generation and caspase 3 activation in IEC-6 cells. The cytotoxicity of MTX was reduced in IEC-6 cells by the 24 h pre-treatment of lutein. We found that pre-treatment of lutein significantly reduces MTX-induced ROS and apoptosis. The expression of SOD was up-regulated by the pre-treatment of lutein in the MTX-treated IEC-6 cells. These results indicated that lutein can protect IEC-6 cells from the chemo-drugs induced damage through increasing ROS scavenging ability.

Conclusion

The MTX-induced apoptosis of IEC-6 cells was shown to be repressed by the pre-treatment of lutein, which may represent a promising adjunct to conventional chemotherapy for preventing intestinal damages.

Synergistic effect of aged garlic extract and naltrexone on improving immune responses to experimentally induced fibrosarcoma tumor in BALB/c mice

Background:

Garlic, a medicinal plant, and Naltrexone (NTX), an opioid receptor antagonist, both have immunomodulatory and antitumor effects. Current study was designed to evaluate synergistic antitumor effects of aged garlic extract (AGE) and NTX.

Materials and Methods:

WEHI-164 fibrosarcoma cells were implanted subcutaneously on day 0 into right flank of 80 BALB/c mice at age of 8 weeks. Mice were randomly categorized in four separate groups: The first group received AGE (100 mg/kg, i.p.), the second group received NTX (0.5 mg/kg, i.p.), the third group received both of them, and the fourth group received phosphate buffered saline as control group. Treatments were administered three times per week. Tumor growth was measured and morbidity was recorded. Subpopulations of CD4+/CD8+ T cells were determined using flowcytometery. WEHI-164 cell specific cytotoxicity of splenocytes and in vitro production of interferon-gamma (IFN-γ) and interleukin-4 (IL-4) cytokines were measured. All statistical analyses were conducted with SPSS 16 software and P < 0.05 was considered to be statistically significant.

Results:

The mice who received AGE+NTX had significantly longer survival time compared with the mice treated with AGE or NTX alone. An enhanced inhibitory effect on tumor growth was seen in combination therapy group. The CD4+/CD8+ ratio and in vitro IFN-γ production of splenocytes were significantly increased in AGE+NTX and NTX groups. WEHI-164 specific cytotoxicity of splenocytes was also significantly increased at 25:1 E:T ratio in AGE+NTX treated mice. Coadministration of AGE with NTX resulted in improvement of immune responses against experimentally implanted fibrosarcoma tumors in BALB/c mice.

Conclusions:

AGE showed synergistic effects with NTX on inhibition of tumor growth and increment of survival times.

Biochemically and histopathologically comparative review of thiamine's and thiamine pyrophosphate's oxidative stress effects generated with methotrexate in rat liver

Background

Oxidative liver injury occurring with methotrexate restricts its use in the desired dose. Therefore, whether or not thiamine and thiamine pyrophosphate, whose antioxidant activity is known, have protective effects on oxidative liver injury generated with methotrexate was comparatively researched in rats using biochemical and histopathological approaches.

Material/Methods

Thiamine pyrophosphate+methotrexate, thiamine+methotrexate, and methotrexate were injected intraperitoneally in rats for 7 days. After this period, all animals’ livers were excised, killing them with high-dose anesthesia, and histopathologic and biochemical investigations were made.

Result

Biochemical results demonstrated a significant elevation in level of oxidant parameters such as MDA and MPO, and a reduction in antioxidant parameters such as GSH and SOD in the liver tissue of the methotrexate group. Also, the quantity of 8-OHdG/dG, a DNA injury product, was higher in the methotrexate group with high oxidant levels and low antioxidant levels, and the quantity of 8-OHdG/dG was in the thiamine pyrophosphate group with low oxidant levels and high antioxidant levels. In the thiamine and control groups, the 8-OHdG/dG rate was 1.48±0.35 pmol/L (P>0.05) and 0.55±0.1 pmol/L (P<0.0001). Thiamine pyrophosphate significantly decreased blood AST, ALT and LDH, but methotrexate and thiamine did not decrease the blood levels of AST, ALT and LDH. Histopathologically, although centrilobular necrosis, apoptotic bodies and inflammation were monitored in the methotrexate group, the findings in the thiamine pyrophosphate group were almost the same as in the control group.

Conclusions

Thiamine pyrophosphate was found to be effective in methotrexate hepatotoxicity, but thiamine was ineffective.

Immunomodulatory activity of aged garlic extract against implanted fibrosarcoma tumor in mice

Background:

Garlic is known as a medicinal herb with broad therapeutic properties ranging from antibacterial to anticancer and even anticoagulant.

Aim:

Current study was designed to evaluate antitumor effects of aged garlic extract (AGE) on fibrosarcoma tumor in BALB/c mice.

Materials and Methods:

WEHI-164 fibrosarcoma cells were implanted subcutaneously on day zero into right flank of 40 BALB/c mice aged eight weeks. Mice were randomly categorized in two separate groups: 1^st received AGE (100 mg/kg, intraperitoneally), 2^nd group as control received phosphate buffered saline, (PBS). Treatments were done three times per week. Tumor growth was measured and morbidity was recorded. Subpopulations of CD4+/CD8+ T cells were determined using flow cytometry. WEHI-164 cell specific cytotoxicity of splenocytes and in vitro production of gamma-interferon, (IFN-γ) and Interleukin-4, (IL-4) cytokines were measured.

Results:

The mice received AGE had significantly longer survival time compared to control mice. The inhibitory effect on tumor growth was seen in AGE treated mice. The CD4+/CD8+ ratio and in vitro IFN-γ production of splenocytes were significantly increased in AGE group.

Conclusions:

Administration of AGE resulted in improved immune responses against experimentally implanted fibrosarcoma tumors in BALB/c mice. AGE showed significant effects on inhibition of tumor growth and longevity of survival times.

Salvia miltiorrhiza causes tonic contraction in rat ileum through Ca²⁺-calmodulin pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Danshen, root of Salvia miltiorrhiza (SM), has been traditionally used in Chinese medicine for the treatment of heart, abdomen, gurgling in the intestines, and relieving fullness. However, the effects of SM on intestine have rarely been done to date.

AIM OF THE STUDY

To investigate the contraction effect of SM on isolated rat ileum and its mechanisms involved.

MATERIALS AND METHODS

The isometric contractions of ileum segments were investigated in organ baths for spontaneous activity and response to ethanolic extracts of SM. To determine the contraction mechanism caused by SM extracts, atropine (a muscarinic receptor antagonist), tetrodotoxin (TTX, a sodium channel blocker), nifedipine (a calcium channel blocker), Ca(2+) free Krebs solution with EGTA, or trifluoperazine (TFP, a calmodulin blocker) was administered and its response to cumulative dosages of SM extracts were examined. The effect of SM extracts on Ca(2+) signaling in the intestinal epithelial cell-6 (IEC-6) was examined using fura-2 as a Ca(2+) indicator.

RESULTS

SM extracts caused dose-dependent tonic contraction on rat ileum in ex vivo organ bath studies. The contraction induced by SM extracts was not inhibited by atropine, TTX, nifedipine, or in Ca(2+) free solution. However, the ileal contractions induced by SM extracts were significantly inhibited by TFP in a dose-dependent manner. In IEC-6 cells, the SM extracts induced extracellular Ca(2+) entry and massive intracellular Ca(2+) release in Ca(2+)-contained medium, and induced intracellular Ca(2+) release in Ca(2+)-free medium.

CONCLUSION

These results demonstrate that SM extracts cause ileal contraction through the Ca(2+)-calmodulin pathway.

Intervention of alpha-lipoic acid ameliorates methotrexate-induced oxidative stress and genotoxicity: A study in rat intestine

Methotrexate (MTX) is an anti-metabolite, widely used in the cancer chemotherapy and rheumatoid arthritis. However, its long-term clinical use is restricted on account of its severe intestinal toxicity. The present study was aimed to investigate the intestinal toxicity of MTX and the possible protective effect of alpha-lipoic acid (LA) on Sprague-Dawley rats. MTX-induced intestinal toxicity was evaluated at the dose of 2.5mg/kg for short-term (5 days treatment) and 1mg/kg for long-term (5 days in a week for four consecutive weeks treatment) study. The possible protective effect of LA was evaluated in both short- as well as long-term study in a dose-dependent manner. MTX treatment induced diarrhoea and mortality in rats, indicating its severe toxicity in the target organ of investigation, i.e., intestine. Further, the intestinal toxicity of MTX was assessed by evaluating different parameters of oxidative stress, DNA damage, cytotoxicity as well as histological changes. Immunostaining for p53 revealed higher genotoxic assault in the intestinal cells due to MTX treatment. Pretreatment of rats with LA led to significant decrease in the oxidative stress, DNA damage, cellular damage, inflammatory changes and apoptosis as determined by malondialdehyde level, glutathione level, comet assay parameters, histological evaluation, immunostaining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. In the present investigation, we report that LA pretreatment ameliorates MTX-induced intestinal toxicity in rat as evident from the protection against oxidative stress, decrease in DNA damage and protection of cellular morphology as well as improvement in the stool consistency and animal survival rate.