Evening primrose oil and celecoxib inhibited pathological angiogenesis, inflammation, and oxidative stress in adjuvant-induced arthritis: novel role of angiopoietin-1.

Rheumatoid arthritis is a chronic inflammatory disease characterized by overproduction of inflammatory mediators along with undermined oxidative defensive mechanisms. Pathological angiogenesis was found to play a critical role in the progression of this disease. The current study was carried out to evaluate the anti-angiogenic, anti-inflammatory, and anti-oxidant effects of evening primrose oil (EPO), rich in gamma linolenic acid (GLA), either alone or in combination with aspirin or celecoxib, on adjuvant-induced arthritis. Arthritis was induced by subcutaneous injection of complete Freund's adjuvant (CFA) in the right hind paw of male albino rats. All treatments were administered orally from day 0 (EPO, 5 g/kg b.w.) or day 4 (celecoxib, 5 mg/kg; aspirin, 150 mg/kg) till day 27 after CFA injection. In the arthritic group, the results revealed significant decrease in the body weight and increase in ankle circumference, plasma angiopoietin-1 (ANG-1) and tumor necrosis factor-alpha (TNF-α) levels. Anti-oxidant status was suppressed as manifested by significant decline in reduced glutathione content along with decreased enzymatic activity of superoxide dismutase and increased lipid peroxidation. Oral administration of EPO exerted normalization of body weight, ANG-1, and TNF-α levels with restoration of activity as shown by reduced malondialdehyde levels. Moreover, histopathological examination demonstrated that EPO significantly reduced the synovial hyperplasia and inflammatory cells invasion in joint tissues, an effect that was enhanced by combination with aspirin or celecoxib. The joint use of GLA-rich natural oils, which possess anti-angiogenic, anti-inflammatory, and anti-oxidant activities, with traditional analgesics represents a promising strategy to restrain the progression of rheumatoid arthritis.

Deletion of thioredoxin-interacting protein preserves retinal neuronal function by preventing inflammation and vascular injury.

BACKGROUND AND PURPOSE: Retinal neurodegeneration is an early and critical event in several diseases associated with blindness. Clinically, therapies that target neurodegeneration fail. We aimed to elucidate the multiple roles by which thioredoxin-interacting protein (TXNIP) contributes to initial and sustained retinal neurodegeneration. EXPERIMENTAL APPROACH: Neurotoxicity was induced by intravitreal injection of NMDA into wild-type (WT) and TXNIP-knockout (TKO) mice. The expression of apoptotic and inflammatory markers was assessed by immunohistochemistry, elisa and Western blot. Microvascular degeneration was assessed by periodic acid-Schiff and haematoxylin staining and retinal function by electroretinogram. KEY RESULTS: NMDA induced early (1 day) and significant retinal PARP activation, a threefold increase in TUNEL-positive nuclei and 40% neuronal loss in ganglion cell layer (GCL); and vascular permeability in WT but not TKO mice. NMDA induced glial activation, expression of TNF-α and IL-1ß that co-localized with Müller cells in WT but not TKO mice. In parallel, NMDA triggered the expression of NOD-like receptor protein (NLRP3), activation of caspase-1, and release of IL-1ß and TNF-α in primary WT but not TKO Müller cultures. After 14 days, NMDA induced 1.9-fold microvascular degeneration, 60% neuronal loss in GCL and increased TUNEL-labelled cells in the GCL and inner nuclear layer in WT but not TKO mice. Electroretinogram analysis showed more significant reductions in b-wave amplitudes in WT than in TKO mice. CONCLUSION AND IMPLICATIONS: Targeting TXNIP expression prevented early retinal ganglion cell death, glial activation, retinal inflammation and secondary neuro/microvascular degeneration and preserved retinal function. TXNIP is a promising new therapeutic target for retinal neurodegenerative diseases.

15-PGDH inhibitors: the antiulcer effects of carbenoxolone, pioglitazone and verapamil in indomethacin induced peptic ulcer rats.

BACKGROUND AND AIM: 15-hydroxyprostaglandin dehydrogenase (15-PGDH) is the enzyme responsible for prostaglandins (PGs) metabolism. PGs have an important role in the protection of stomach mucosa against destructive stimuli. The aim of the present study is to investigate the inhibitory effect of carbenoxolone, pioglitazone and verapamil on 15-PGDH enzyme. MATERIALS AND METHODS: The experiments were carried out in the Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt from May 2011 to August 2011. Adult male albino rats were fasted for 18 hours before administration of high dose of indomethacin (30 mg/kg, p.o.), except for the negative control group which received saline only, followed by pyloric ligation to induce acute gastric ulcers. The rats were pretreated orally with saline, pioglitazone (20 mg/kg), verapamil (25 mg/kg), carbenoxolone (30 mg/kg) or their combinations 30 minutes before indomethacin. The rats were sacrificed after four hours of pyloric ligation. The effects of the previous treatments on the ulcer index (Ui), the microscopic appearance of gastric mucosa, the gastric acid output, the gastric barrier mucus content, and 15-PGDH enzyme activity were determined. RESULTS: Indomethacin resulted in severe ulceration and increased gastric acid output (p < 0.05) compared to negative control. The rats pretreated with carbenoxolone, pioglitazone, verapamil had reduced ulcer index, gastric acid output and 15-PGDH activity (p < 0.05) compared to either indomethacin group or the negative control group. Individual treatments with carbenoxolone, pioglitazone or verapamil increased gastric barrier mucus (p < 0.05) compared to either indomethacin group or the negative control group. The combinations of verapamil with either carbenoxolone or pioglitazone caused further reduction in ulcer index, gastric acid output and 15-PGDH activity (p < 0.05), while causing further increase in gastric barrier mucus (p < 0.05) compared to their respective individual treatment group. CONCLUSIONS: The antiulcer properties of pioglitazone and verapamil are, in part, consequences of their inhibitory effect on the enzyme 15-PGDH, responsible for PGs degradation, and the resultant prolongation of PGE2 biological activity in rat stomach mucosa.

Eicosapentaenoic acid ablates valproate-induced liver oxidative stress and cellular derangement without altering its clearance rate: dynamic synergy and therapeutic utility.

The omega-3 fatty acid eicosapentaenoic acid (EPA) is a superb nature's medicine, with still unfolding health benefits. Because hepatotoxicity is a prominent adverse drug reaction, we currently attempted a new approach in which EPA was challenged to both alleviate hepatotoxicity and provide synergy with anticonvulsant effects of valproate (VPA). Besides, we verified whether EPA may kinetically modulate the clearance rate of VPA. VPA (500mg/kg p.o., for 2weeks) caused rat hepatotoxicity that was manifested as notable (2- to 4-fold) rise in serum liver enzymes (GGT, ALT, and ALP), increased hepatic levels of lipid peroxides and TNF-α (3- and 7-fold) and activity of myeloperoxidase (MPO, 4-fold), lowering of serum albumin (42%), and depletion of liver reduced glutathione (GSH, 36%). Furthermore, histopathologic examination revealed hepatocellular degeneration, focal pericentral necrosis, infiltration of inflammatory cells, and steatosis. Joint treatment with EPA (300mg/kg) blunted the oxidative stress, TNF-α levels and MPO activity, while enhanced levels of serum albumin and hepatic GSH. EPA also ameliorated most of the hepatocellular anomalies evoked by VPA. Additionally, in a mouse PTZ convulsion model, EPA markedly augmented the anticonvulsant effects of VPA far beyond their single responses. On the other hand, pharmacokinetic analyses revealed that joint EPA administration had no effect on serum VPA concentrations. Collectively, results demonstrate for the first time that the ω-3 FA (EPA) markedly alleviated VPA-induced hepatotoxicity, oxidative stress, and inflammation, while enhanced its anticonvulsant effects without altering its clearance. Therapeutically, these protective and synergy profiles for EPA foster a more safe and efficacious drug combination regimen than VPA.

Evaluation of renal protective effects of the green-tea (EGCG) and red grape resveratrol: role of oxidative stress and inflammatory cytokines.

Epigallocatechin-gallate (EGCG) and resveratrol (RSVL) are two of the most promising natural medicines. We verified their capacity to ameliorate cisplatin (CP)-induced disruption of renal glomerular filtration rate (GFR) in rats, and sought the mediatory involvement of lipid peroxidation (malondialdehyde [MDA]-level) and inflammatory cytokine (TNF-α) therein. CP (10 mg kg⁻¹), a single i.p. dose, disrupted GFR (11-fold-rise in proteinuria, 2-5-fold rise in serum creatinine/urea levels) after 7 days, and killed all animals after 10 days. Kidney-homogenates from CP-treated rats displayed higher MDA and TNF-α, but lower reduced-glutathione (GSH) levels. Rats treated with EGCG (50 mg kg⁻¹, but not 25 mg kg⁻¹) had no fatalities and showed significantly-recovered GFR; while their kidney-homogenates had markedly reduced MDA, TNF-α and enhanced GSH levels at 7 days. Conversely, RSVL or quercetin (25, 50 mg kg⁻¹) neither improved GFR nor reduced (MDA)/TNF-α levels after 7 days. Resuming treatment with 50 mg kg⁻¹ for 10 days rescued only 25% of animals (p > 0.05). Correlation studies showed a significant association between creatinine level, and each of MDA (r = 0.91), GSH (r = -0.87), and TNF-α (0.91). The study showed for the first time that EGCG, unlike RSVL, can protect against CP-induced nephrotoxicity. At the molecular level, CP triggers a high level of oxidative stress and systemic inflammation, events that were all abrogated with EGCG; better than RSVL or quercetin.