Fenofibrate ameliorates olanzapine's side effects without altering its central effect: emphasis on FGF-21-adiponectin axis

The present work was designed to investigate whether fenofibrate could ameliorate olanzapine deleterious effect on insulin resistance via its effect on fibroblast growth factor-21 (FGF-21)-adiponectin axis without affecting olanzapine antipsychotic effect in postweaning socially isolated reared female rats. Treatment with olanzapine (6 mg/kg, intraperitoneally) or fenofibrate (100 mg/kg, orally) have been started 5 weeks after isolation, then behavioral tests, hippocampal content of neurotransmitters, and brain-derived neurotrophic factor (BDNF) were assessed. Moreover, insulin resistance, lipid profile, FGF-21, adiponectin, inflammatory, and oxidative stress markers of adipose tissue were assessed. Treatment of isolated-reared animals with olanzapine, or fenofibrate significantly ameliorated the behavioral and biochemical changes induced by postweaning social isolation. Co-treatment showed additive effects in improving hippocampal BDNF level. Besides, fenofibrate reduced the elevation in weight gain, adiposity index, insulin resistance, lipid profile, and FGF-21 level induced by olanzapine treatment. Also, fenofibrate increased adiponectin level which was reduced upon olanzapine treatment. Moreover, fenofibrate improved both adipose tissue oxidative stress and inflammatory markers elevation as a result of olanzapine treatment. Fenofibrate could ameliorate olanzapine-induced insulin resistance without affecting its central effect in isolated reared rats via its action on FGF-21-adiponectin axis.

Thymoquinone attenuates isoproterenol-induced myocardial infarction by inhibiting cytochrome C and matrix metalloproteinase-9 expression

Thymoquinone (TQ) is the main active constituent of Nigella sativa. The present study aimed to investigate the effect of TQ on apoptotic parameters and MMP-9 expression in isoproterenol (ISP)-induced myocardial infarction (MI). TQ was given once daily for 7 days at doses of 10 and 20 mg/kg orally with ISP (86 mg/kg; s.c.) administered on the sixth and seventh days. TQ pre-treatment protected against ISP-induced MI as approved by normalisation of electrocardiogram (ECG) and b (CK)-MB, minimal histopathological changes, and reduction of the infarction size. Effects of TQ could be supported by its antioxidant activity, evidenced by the increase of cardiac reduced glutathione and total serum antioxidant capacity, and the inhibition of ISO-induced lipid peroxidation. TQ anti-inflammatory activity was associated with reduced expression of NF-κB and TNF-α. TQ ameliorated cardiomyocytes^, apoptotic pathways by inhibiting both the intrinsic pathway, via reducing cytoplasmic cytochrome C, and the extrinsic pathway, by inhibiting TNF-α and caspases, and the effect of TQ was dose-dependent. Moreover, TQ reduced the expression of metalloproteinase (MMP)-9, which is considered as a prognostic marker of ventricular remodelling, recommending that TQ can be used as a possible supplement to minimise post-MI changes. So, we conclude that TQ antiapoptotic activity and the inhibitory modulation of MMP-9 expression contribute to TQ protective effects in MI. To our knowledge, this is the first study reporting the effect of TQ on cytochrome c activity and MMP-9 expression in MI.

'Methyl palmitate attenuates adjuvant induced arthritis in rats by decrease of CD68 synovial macrophages

The study was designed to investigate the potential anti-arthritic effects of methyl palmitate in an adjuvant arthritis model in rats that shares many histopathological similarities with human RA. The underlying mechanism and its effect on CD68 macrophages were investigated, as a further argument to its possible efficacy in RA treatment. A normal control group was injected only with saline, arthritic group, and three treatment groups with CFA induced arthritis received methyl palmitate (MP) at three different doses (75, 150, 300 mg/kg/week for 3 weeks, intraperitoneal). The degree of ipsilateral paw swelling, ankle diameter, spleen index, thymus index and the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β were measured. In addition, the underlying molecular mechanism was investigated using CD68 expression. Methyl palpitate significantly and dose dependently decreased the arthritic symptoms as measured by ipsilateral paw volume and ankle diameter. It showed no effect on body weight but significantly decreased splenic, thymus index, serum TNF-α and IL-1β. CD68 macrophages expression and the overall synovial inflammatory cellularity were halted. Methyl palmitate exhibits significant anti-inflammatory and exerts a potential anti-arthritic effect in a rat model of adjuvant induced arthritis. Furthermore, it inhibits expression of synovial CD68 macrophage that validate its therapeutic potential adjuvant arthritis.

Putative anti-inflammatory, antioxidant, and anti-apoptotic roles of the natural tissue guardian methyl palmitate against isoproterenol-induced myocardial injury in rats

Background

Myocardial injury is considered as a worldwide main cause of morbidity and mortality. The present study aimed to investigate the probable cardioprotective activity of the naturally occurring endogenous fatty acid ester methyl palmitate (MP) against isoproterenol (ISO)-induced myocardial injury in rats and the possible underlying molecular mechanisms. The study was carried out in two consecutive sets of experiments; the first set screened the cardioprotective dose of MP in ISO-intoxicated rats. In the second set, forty male Sprague Dawley rats received either MP (150 mg/kg, p.o) three times/week for 2 weeks and/or 2 consecutive doses of ISO separated by 24 h (85 mg/kg, s.c) on the 13th and 14th days. Different cardiotoxicity and oxidative stress markers were assessed. Furthermore, endothelial nitric oxide synthase (eNOS) levels were determined. For detection of apoptosis, Bax, Bcl-2, and caspase 3 were estimated. To assess inflammation, toll-like receptor 4 (TLR-4) and tumor necrosis factor-alpha (TNF-α) were measured using ELISA. Meanwhile, nuclear factor kappa B (NF-kB) and cyclooxygenase-2 (COX-2) were detected immunohistochemically.

Results

Pretreatment with MP significantly ameliorated the cardiotoxicity and oxidative stress markers. It also markedly elevated eNOS content, decreased apoptotic marker expression, and mitigated TLR-4 activation and other inflammatory markers. Electrocardiography and histopathological examination also confirmed the cardioprotective effect of MP.

Conclusion

The findings of this study indicated that MP possesses a potent cardioprotective activity against ISO-induced myocardial injury through its significant antioxidant, anti-apoptotic, anti-inflammatory, and vasodilatation activities.

Graphical abstract

Mechanistic insights to the cardioprotective effect of blueberry nutraceutical extract in isoprenaline-induced cardiac hypertrophy

BACKGROUND

Lowbush blueberry extract (Vaccinium angustifolium) is abundant with polyphenols (such as chlorogenic acid) with high antioxidant profile. It has received great interest due to its protective role in many disorders such as heart diseases and neurological disorders.

HYPOTHESIS

We hypothesized that blueberry leaf extract might have a protective effect against cardiac hypertrophy via suppressing oxidative stress, inflammation and fibrosis.

METHOD

Blueberry leaf nutraceutical extract was administered orally to male albino rats at three different doses (25, 50 and 100 mg/kg/day of the extract, equivalent to 3.4, 6.8 and 13.6 mg of chlorogenic acid, respectively) once daily for 28 consecutive days against a dose of isoprenaline (ISO) (5 mg/kg) for 14 days.

RESULTS

The results indicated that isoprenaline induced significant myocardial damage, characterized by conduction abnormalities, increased heart-to-body weight ratio, increased serum CKMB, AST, c-TnI and LDH. Pretreatment with blueberry extract at a dose of 50 mg/kg/day (equivalent to 6.8 mg chlorogenic acid) protected against ISO-induced ECG changes, leakage of cardiac enzymes and histopathological changes. Also, ISO caused significant glutathione depletion, lipid peroxidation and reduction in activities of antioxidant catalase enzyme. These effects were prevented by pretreatment with blueberry extract. Additionally, ISO elicited inflammatory effects by increasing the expression of NF-κB, COX-2, TNF-α and IL-6 while pretreatment with blueberry extract significantly inhibited these inflammatory responses. Furthermore, ISO induced fibrosis by increasing the level of TGF-β while pretreatment with blueberry extract significantly reduced it.

CONCLUSION

These findings indicate that blueberry leaf extract possessed a potent protective effect against ISO-induced cardiac hypertrophy via suppressing oxidative stress, inflammation and fibrosis.

Deferoxamine alleviates liver fibrosis induced by CCl4 in rats

Several chronic liver diseases can lead to the occurrence of hepatic fibrosis through the accumulation of iron, which causes induction of oxidative stress and consequently activation of fibrogenesis. The present study was designed to investigate the potential antifibrotic and anti-oxidant effects of deferoxamine (DFO), a well-known iron chelator in an experimental rat model of liver injury using carbon tetrachloride (CCl4 ). First, the potential effective dose of DFO was screened against CCl4 -induced acute hepatotoxicity. Then, rats were co-treated with DFO (300 mg/kg, i.p.) for 6 weeks starting from the third week of CCl4 induction of chronic hepatotoxicity. Liver function was assessed in addition to histopathological examination. Furthermore, oxidative stress and fibrosis markers were assessed. It was found that treatment of animals with DFO significantly counteracted the changes in liver function; histopathological lesions and hepatic iron deposition that were induced by CCl4 . DFO also significantly counteracted the CCl4 -induced lipid peroxidation increase and reduction in antioxidant activities of superoxide dismutase and glutathione peroxidase enzymes. In addition, DFO ameliorated significantly liver fibrosis markers including hydroxyproline, collagen accumulation, and the expression of the hepatic stellate cells (HSCs) activation marker; alpha smooth muscle actin and transforming growth factor-beta (TGF-β). Together, these findings indicate that DFO possesses a potent antifibrotic effect due to its antioxidant properties that counteracted oxidative stress and lipid peroxidation and restored antioxidant enzymes activities as well as reducing HSCs activation and fibrogenesis.

Prophylactic L-arginine and ibuprofen delay the development of tactile allodynia and suppress spinal miR-155 in a rat model of diabetic neuropathy

Diabetic neuropathy (DN) is a common complication of diabetes mellitus that is hardly reversible at the late stages. Since treatment of neuropathic pain is predominantly symptomatic, a prophylactic measure would be useful. Both ibuprofen and L-arginine exert antiallodynic effects on chronic constriction injury (CCI)-induced cold allodynia. Furthermore, ibuprofen is effective in CCI-induced mechanical allodynia. The aim of the study was to assess the antiallodynic effect of prophylactic ibuprofen and L-arginine in streptozotocin-induced DN in rats and to further investigate the role of spinal miR-155 and nitric oxide (NO) in this effect. Tactile allodynia was assessed weekly by von Frey filaments. Oral daily administration of ibuprofen, L-arginine and their combination, for 4 weeks starting 1 week after streptozotocin injection (ie, before the development of tactile allodynia), resulted in a significant decrease of tactile allodynia compared with the control diabetic group. This was evident in the fifth week of the experiment. The 3 treatments prevented the decrease in muscle fiber diameter and epidermal thickness, seen in the control diabetic group. Furthermore, ibuprofen, L-arginine and their combination prevented the increase in the spinal NO level and miRNA-155, seen in the control diabetic group. In conclusion, both ibuprofen and L-arginine delayed the development of behavioral and histologic changes of DN, with concomitant suppression of spinal miR-155 and NO level. L-arginine being tolerable may be useful prophylactically in diabetic patients.

Thymoquinone alleviates nonalcoholic fatty liver disease in rats via suppression of oxidative stress, inflammation, apoptosis

Nonalcoholic steatohepatitis (NAFLD) is a progressive form of liver disease that leads to advanced fibrosis. The present study was designed to assess the hepatoprotective effect of thymoquinone (TQ) on liver functions, insulin resistance, and PPAR-γ expression in NAFLD. Rats were divided into two main groups: one fed with normal rat chow diet and the other with high-fat high-cholesterol diet group for 6 weeks. Every group was subdivided into three subgroups (n = 8): treated with saline, low dose TQ (10 mg/kg), high dose TQ (20 mg/kg). High fat high cholesterol diet caused marked liver damage as noted in histopathology and significant increase in liver index, liver enzymes. There was significant increase in the insulin resistance, serum cholesterol, triglyceride, PPAR-γ gene overexpression with significant decrease in HDL. Additionally, oxidative stress increased by measuring MDA associated with significant decrease in serum total antioxidant capacity. As markers of inflammation, hepatic TNF-α was significantly increased with decrease in IL10. Further, there was increase in BAX protein with decrease in Bcl as compared to control group. This model of 6 weeks high-fat high-cholesterol diet showed minimal fibrosis as noticed by increase MMP2 and Masson trichrome satin. Co-treatment with TQ improved all previous parameters. High dose was more effective, although mostly non-statistically significant. TQ may have a promising agent to improve hepatic steatosis, oxidative stress; inflammatory, apoptotic status, fibrosis and so prevent liver damage in patients with NAFLD. Although PPAR-γ was significantly under-expressed by TQ, insulin resistance was improved significantly suggesting a role of liver damage.

Antifibrotic mechanism of deferoxamine in concanavalin A induced-liver fibrosis: Impact on interferon therapy

Iron-overload is a well-known factor of hepatotoxicity and liver fibrosis, which found to be a common finding among hepatitis C virus patients and related to interferon resistance. We aimed to elucidate the potential antifibrotic effect of deferoxamine; the main iron chelator, and its additional usefulness to interferon-based therapy in concanavalin A-induced immunological model of liver fibrosis. Rats were treated with deferoxamine and/or pegylated interferon-α for 6 weeks. Hepatotoxicity indices, oxidative stress, inflammatory and liver fibrosis markers were assessed. Concanavalin A induced a significant increase in hepatotoxicity indices and lipid peroxidation accompanied with a significant depletion of total antioxidant capacity, glutathione level and superoxide dismutase activity. Besides, it increased CD4(+) T-cells content and the downstream inflammatory cascades, including NF-κB, TNF-α, iNOS, COX-2, IL-6 and IFN-γ. Furthermore, α-SMA, TGF-β1 and hydroxyproline were increased markedly, which confirmed by histopathology. Treatment with either deferoxamine or pegylated interferon-α alone reduced liver fibrosis markers significantly and improved liver histology. However, some of the hepatotoxicity indices and oxidative stress markers did not improve upon pegylated interferon-α treatment alone, besides the remarkable increase in IL-6. Combination therapy of deferoxamine with pegylated interferon-α further improved all previous markers, ameliorated IL-6 elevation, as well as increased hepcidin expression. In conclusion, our study provides evidences for the potent antifibrotic effects of deferoxamine and the underlying mechanisms that involved attenuating oxidative stress and subsequent inflammatory cascade, as well as the production of profibrogenic factors. Addition of deferoxamine to interferon regimen for HCV patients may offer a promising adjuvant modality to enhance therapeutic response.

Hypericum Perforatum Decreased Hippocampus TNF-α and Corticosterone Levels with No Effect on Kynurenine/Tryptophan Ratio in Bilateral Ovariectomized Rats

The present study was designed to investigate the effect Hypericum Perforatum (HP), on behavioral changes, corticosterone, TNF-α levels and tryptophan metabolism and disposition in bilateral ovariectomized rats compared to 17α -ethinylestradiol. Behavioral analysis by measuring immobility time in forced swimming test and open field test, serum and hippocampal corticosterone and TNF-α along with hippocampal kynurenine/tryptophan ratio were determined in mature ovariectomized rats treated orally either by HP at three different doses 125, 250, and 500 mg/kg/day or by 17α-ethinylestradiol 30 µg/kg/day for 30 days. Ovariectomized rats showed significant increase in immobility time in the forced swimming test. Along with elevation in serum and hippocampal TNF-α and corticosterone levels associated with significant increase in hippocampal kynurenine/tryptophan ratio. Immobility time in the forced swimming test was decreased in rats treated by different doses of HP in a dose dependent manner and 17α-ethinylestradiol with no concomitant changes in the open field test. Only Rats treated with HP exhibited significant decrease in the elevated serum and hippocampal TNF-α and corticosterone, which couldn't explain the associated insignificant effect on hippocampaus kynurenine/tryptophan ratio in comparison to ovariectomized untreated rats. It is concluded that increased tryptophan metabolism toward kynurenine secondary to elevated corticosterone and TNF-α might be one of the pathohphysiological mechanisms that could explain depression like state observed in this rat model. Further, the observed attenuating effect of HP on TNF-α and corticosterone could contribute in its antidepressant effect in this animal model by other ways than their effects on tryptophan-kynurenine metabolism pathway.

Bupropion effects on high-fat diet-induced steatohepatitis and endothelial dysfunction in rats: role of tumour necrosis factor-alpha

OBJECTIVES

This study aimed to elucidate the effect of bupropion (BUP) on high-fat diet (HFD)-treated rats that is to say the action of BUP on diabetes and hyperlipidemia with its consequences on liver and endothelial function.

METHODS

Male Wistar rats were fed HFD or normal chow for 15 weeks then given either BUP (50 mg/kg) or distilled water by gavage for 4 weeks. The effect of BUP on diabetes, hyperlipidemia, hepatic and vascular functions as well as tumour necrosis factor-alpha (TNF)-α were assessed. The intima-media thickness of the aorta was evaluated.

KEY FINDINGS

BUP significantly decreased serum lipid, liver enzyme, homeostasis model assessment for insulin resistance (HOMA-IR), serum TNF-α and the impaired glucose tolerance. Liver from rats with non-alcoholic steatohepatitis (NASH) demonstrated significant higher TNF-α level, inflammatory cell infiltration, ballooning and steatosis which significantly ameliorated by BUP treatment. Neither intima/media ratio nor vascular reactivity to acetylcholine is improved by BUP treatment.

CONCLUSIONS

NASH induced by a HFD was associated with hyperlipidemia, insulin resistance, endothelial dysfunction and increase in liver TNF-α. All of these may contribute to the pathogenesis of NASH. BUP has potential role in improving metabolic and hepatic function with negative vascular effect. Since BUP is a well-known antidepressant, it will be a candidate drug in treatment of depression in hepatic diseased or metabolic disturbed patients.

Targeting TNF-α and NF-κB activation by bee venom: role in suppressing adjuvant induced arthritis and methotrexate hepatotoxicity in rats

Low dose methotrexate is the cornerstone for the treatment of rheumatoid arthritis. One of its major drawbacks is hepatotoxicity, resulting in poor compliance of therapy. Dissatisfied arthritis patients are likely to seek the option of complementary and alternative medicine such as bee venom. The combination of natural products with modern medicine poses the possibility of potential interaction between the two groups and needs investigation. The present study was aimed to investigate the modulatory effect of bee venom acupuncture on efficacy, toxicity, and pharmacokinetics and tissue disposition of methotrexate. Complete Freund's adjuvant induced arthritic rats were treated for 3 weeks with methotrexate and/or bee venom. Arthritic score, ankle diameter, paw volume and tissue expression of NF-κB and TNF-α were determined to assess anti-arthritic effects, while anti-nociceptive effects were assessed by gait score and thermal hyperalgesia. Methotrexate toxicity was assessed by measuring serum TNF-α, liver enzymes and expression of NF-κB in liver. Combination therapy of bee venom with methotrexate significantly improved arthritic parameters and analgesic effect as compared to methotrexate alone. Bee venom ameliorated serum TNF-α and liver enzymes elevations as well as over expression of NF-κB in liver induced by methotrexate. Histological examination supported the results. And for the first time bee venom acupuncture was approved to increase methotrexate bioavailability with a significant decrease in its elimination.

CONCLUSION

bee venom potentiates the anti-arthritic effects of methotrexate, possibly by increasing its bioavailability. Also, it provides a potent anti-nociceptive effect. Furthermore, bee venom protects against methotrexate induced hepatotoxicity mostly due to its inhibitory effect on TNF-α and NF-κB.