Cinnamic Acid Ameliorates Acetic Acid-induced Inflammatory Response through Inhibition of TLR-4 in Colitis Rat Model.

BACKGROUND: Cinnamic acid, an active compound in cinnamon spp., has anti-inflammatory and antioxidant characteristics and is favorable in managing inflammatory bowel diseases. OBJECTIVES: Evaluate cinnamic acid's effects on colitis in rats. METHODS: To induce colitis in experimental rats, excluding the sham group, a 4% intrarectal solution of acetic acid was administered. The rats were then given oral doses of cinnamic acid at 30, 45, and 90 mg/kg for two days. The animals were assessed for macroscopic and microscopic changes, and the levels of inflammatory mediators such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and myeloperoxidase (MPO) were measured using Eliza kits. Additionally, real-time PCR was performed to examine the gene level of toll-like receptor 4 (TLR-4) in the colon. RESULTS: Effective reduction of inflammation in acetic acid-induced colitis was achieved through Cinnamic acid administration at doses of 45 and 90 mg/kg. The decrease was achieved by inhibiting the activities of TNF-α, IL-6, and MPO while downregulating the expression of TLR-4. It is important to note that macroscopic and microscopic evaluations were significant in determining the effectiveness of cinnamic acid in reducing inflammation. CONCLUSION: Downregulation of inflammatory cytokines and TLR-4 expression may contribute to cinnamic acid's anti-inflammatory effect.

Juglone Mediates Inflammatory Bowel Disease Through Inhibition of TLR-4/NF KappaB Pathway in Acetic Acid-induced Colitis in Rats.

BACKGROUND: Juglone is a phenolic bioactive compound with antimicrobial, antitumour, antioxidant, and anti-inflammatory characteristics. Given its anti-inflammatory and antioxidant effects, it was selected for evaluation in the inflammatory bowel diseases (IBD) model. OBJECTIVE: The current study was performed to evaluate the therapeutic impacts of the juglone in acetic acid-induced colitis in male Wistar rats. METHODS: Juglone was extracted from Pterocarya fraxinifolia via maceration method. Colitis was induced in 36 male Wistar rats (n = 6), except in the sham group, 1 ml of acetic acid 4% was administered intrarectally. Twenty-four hours after induction of colitis, in 3 groups, juglone was administered orally (gavage) at 3 doses of 50, 100, and 150 mg/kg for 2 successive days (once a day). Other groups included the control group (only treated with acetic acid), sham group (normal saline), and standard group (Dexamethasone). To evaluate the inflammation sites, macroscopic and microscopic markers were assessed. The mRNA expression of interleukin (IL)-1ß, and tumor necrosis factor-alpha (TNF)-α were assessed by real-time PCR, while myeloperoxidase (MPO) was measured spectrophotometrically. ELISA assay kits were used to determine the colonic levels of SOD, ROS, NF-κB, and TLR-4. RESULTS: Macroscopic and microscopic assessments revealed that juglone significantly decreased colonic tissue damage and inflammation at 150 mg/kg. Juglone at 100, 150 mg/kg significantly decreased the TNF-α, MPO, and TLR-4 levels, as well as the SOD activity. All juglone-treated groups reduced the NF-κB levels compared to the control group (p < 0.001). The compound decreased the IL-1ß, and ROS levels at the concentration of 150 mg/kg. Juglone attenuated colitis symptoms, reduced inflammation cytokines, declined neutrophil infiltration, and suppressed IL- 1ß and TNF-α expressions in acetic acid-induced colitis rats. It may be proposed that juglone improved colitis in animal model through suppression of inflammatory parameters and downregulation of the NF-κB-TLR-4 pathway. CONCLUSION: Juglone exhibited anti-inflammatory and antioxidant effects in the experimental colitis model and could be a therapeutic candidate for IBD. Juglone should be a subject for further animal and clinical trials in IBD models and for safety concerns.

Licofelone Attenuates Acetic Acid-Induced Colitis in Rats Through Suppression of the Inflammatory Mediators.

Licofelone is a dual Cyclooxygenase 1,2 (COX1,2)/5-lipoxygenase) 5-LOX (inhibitor with analgesic and anti-inflammatory effects with possible functions on inflammatory bowel disease (IBD), which is a chronic recurrent condition with no particular treatment. This study evaluated the anti-inflammatory effects of licofelone on acetic acid-induced colitis in rats. Ten groups of male Wistar rats (n = 6) were used. Sham, control group, licofelone at doses of 2.5, 5, and 10 mg/kg, L-NG-nitro arginine methyl ester (L-NAME) (10 mg/kg, i.p.), aminoguanidine (AG) (100 mg/kg, i.p.), 30 min before using licofelone (10 mg/kg). Also, three groups received L-NAME, aminoguanidine, or dexamethasone. Macroscopic, microscopic, and biochemical analysis of myeloperoxidase (MPO), and nuclear factor-kappa B (NF-κB), tumor necrosis factor-α (TNF-α), and interleukin-1ß (IL-1ß), superoxide dismutase (SOD), reactive oxygen species (ROS), and Toll-like receptor 4 (TLR-4) were assessed in colon tissue. Licofelone at a dose of 10 mg/kg attenuated colitis, increased SOD activity, and significantly reduced colonic levels of the abovementioned inflammatory factors. In addition, licofelone improved macroscopic and microscopic symptoms in the acetic acid-induced colitis model. Moreover, the concurrent use of nitric oxide synthase (NOS) inhibitors with 10 mg/kg of licofelone reversed the observed positive effects, demonstrating the function of nitric oxide in IBD pathogenesis and the probable mechanism for licofelone in the healing process of induced colitis. A reduced level of inflammatory factors confirmed the anti-inflammatory activity of licofelone as a dual COX1,2/5-LOX inhibitor. Furthermore, outcomes revealed the protective role of licofelone in treating experimental colitis. The findings are suggestive of the potential use of licofelone in IBD.

The expression, localization and function of α7 nicotinic acetylcholine receptor in rat corpus cavernosum.

OBJECTIVES: Alpha7 nicotinic acetylcholine receptor (α7-nAChR), an emerging pharmacological target for a variety of medical conditions, is expressed in the most mammalian tissues with different effects. So, this study was designed to investigate the expression, localization and effect of α7-nAChR in rat corpus cavernosum (CC). METHODS & KEY FINDINGS: Reverse transcription polymerase chain reaction (RT-PCR) revealed that α7-nAChR was expressed in rat CC and double immunofluorescence studies demonstrated the presence of α7-nAChR in corporal neurons. The rat CC segments were mounted in organ bath chambers and contracted with phenylephrine (0.1 µm -300 µm) to investigate the relaxation effect of electrical field stimulation (EFS,10 Hz) assessed in the presence of guanethidine (adrenergic blocker, 5 µm) and atropine (muscarinic cholinergic blocker, 1 µm) to obtain non-adrenergic non-cholinergic (NANC) response. Cumulative administration of nicotine significantly potentiated the EFS-induced NANC relaxation (-log EC50 = 7.5 ± 0.057). Whereas, the potentiated NANC relaxation of nicotine was significantly inhibited with different concentrations of methyllycaconitine citrate (α7-nAChR antagonist, P < 0.05) in preincubated strips. L-NAME (non-specific nitric oxide synthase inhibitor, 1 µm) completely blocked the neurogenic relaxation induced by EFS plus nicotine. CONCLUSION: To conclude α7-nAChR is expressed in rat CC and modulates the neurogenic relaxation response to nicotine.