Effect of soya phosphatidylcholine and possible underlying mechanism on ischemia/reperfusion injury in isolated perfused rat heart: an experimental and computational study.

This study was designed to assess the effect of soya phosphatidylcholine (SPC) against ischemia/reperfusion (I/R) injury and the possible underlying mechanism using experimental and computational studies. I/R injury was induced by global ischemia for 30 min followed by reperfusion for 120 min. The perfusion of the SPC was performed for 10 min before inducing global ischemia. In the mechanistic study, the involvement of specific cellular pathways was identified using various inhibitors such as ATP-dependent potassium channel (KATP) inhibitor (glibenclamide), protein kinase C (PKC) inhibitor (chelerythrine), non-selective nitric oxide synthase inhibitor (L-NAME), and endothelium remover (Triton X-100). The computational study of various ligands was performed on toll-like receptor 4 (TLR4) protein using AutoDock version 4.0. SPC (100 µM) significantly decreased the levels of cardiac damage markers and %infarction compared with the vehicle control (VC). Furthermore, cardiodynamics (indices of left ventricular contraction (dp/dtmax), indices of left ventricular relaxation (dp/dtmin), coronary flow, and antioxidant enzyme levels were significantly improved as compared with VC. This protective effect was attenuated by glibenclamide, chelerythrine, and Triton X-100, but it was not attenuated by L-NAME. The computational study showed a significant bonding affinity of SPC to the TLR4-MD2 complex. Thus, SPC reduced myocardial I/R injury in isolated perfused rat hearts, which might be governed by the KATP channel, PKC, endothelium response, and TLR4-MyD88 signaling pathway.

Ovalbumin/lipopolysaccharide induced vasculitis in rats: a new predictive model.

OBJECTIVES: Currently, there are several animal models for vasculitis. Ovalbumin and lipopolysaccharide (OVA, LPS) are well established for causing inflammation and used as an adjunct in the vasculitis induction. However, to date, none has established the effect of OVA and LPS in disease induction. Therefore, in the present study, an attempt has been made to develop a new animal model for vasculitis using OVA/LPS in rats. METHODS: A total of 42 Wistar rats were divided randomly into seven groups (n=6/group), normal control, and three different doses (0.5, 1, and 5 mg/kg) of OVA and LPS treated groups. Half of the rats in each group received only intraperitoneal sensitization, while the remaining half rats were additionally subjected to a one-week intranasal challenge. RESULTS: Results showed that both OVA/LPS in their respective groups have significantly increased circulating inflammatory cells, C-reactive protein (CRP), Inflammatory cytokines (IL-1ß, IL-6, TNF-α), Kidney damage markers (BUN, Creatinine), and liver function enzymes (AST, ALT) in a dose-dependent manner. CONCLUSIONS: OVA/LPS induced vascular inflammation in a dose-dependent manner. However, the higher (5 mg/kg) dose of ovalbumin and lipopolysaccharide has contributed to severe vascular inflammation through increasing inflammatory cytokines. These findings suggest that OVA/LPS may contribute as a possible model for vasculitis in rats.

An experimental model of asthma in rats using ovalbumin and lipopolysaccharide allergens.

Asthma is chronic and multi-factorial inflammatory disease hence single allergen induced asthma in an animal is not identical to clinical asthma. Therefore, we developed a novel experimental model of asthma in rats using ovalbumin (OVA) and lipopolysaccharide (LPS) allergens. Rats were divided into four groups; normal (NC), OVA, LPS, and OVA-LPS treated. Rats were sensitized with OVA (100 µg/kg, adsorbed in 100 mg/mL aluminum hydroxide, i.p.), LPS (10 µg/kg, i.p.) and both (OVA-LPS) on 7th, 14th, 21st days and was followed by challenge with OVA (1%w/v), LPS (1%w/v), OVA (0.5%w/v) and LPS (0.5%w/v) for 30 min thrice/week for three weeks in the OVA, LPS and OVA-LPS groups, respectively. On 41 day, lung function parameters (respiration rate, tidal volume, and airflow rate), total and differential leukocytes count in the blood as well as BALf and inflammatory cytokines (IL-4, IL-5, and IL-13) in serum were measured. Histology of lungs was performed. The results suggested that the tidal volume and airflow rate were significantly decreased while respiration rate, total and differential leukocytes count in blood as well as BALf and serum cytokines level were significantly increased in the OVA-LPS as compared to NC, OVA, and LPS. In conclusion, the combination of OVA and LPS induced phenotypes of severe asthma with eosinophilic, neutrophilic and lymphocytic inflammation.

An anti-asthmatic activity of natural Toll-like receptor-4 antagonist in OVA-LPS-induced asthmatic rats.

Toll-like receptor-4 (TLR4) is a key component of the innate immune system and activation of TLR4 signaling has a significant role in the pathogenesis of asthma. Therefore, our objective was to identify the natural TLR4 antagonist and evaluate its activity in experimentally induced asthma. Soya lecithin origin phosphatidylcholine (soya PC) was identified as a natural TLR4 antagonist by computational study. Based on the computational study, TLR4 antagonist activity of soya PC was confirmed in in vitro lipopolysaccharide (LPS)-induced neutrophil adhesion assay. In the in vivo study, rats were sensitized with ovalbumin (OVA) (100 µg/kg, i.p.) on the 7th, 14th and 21st days and challenged intranasally with OVA (100 µg/100 µL) and LPS (10 ng/100 µL), 4 days/wk for 3 weeks. At the end of the experiment, we performed lung function parameters (respiratory rate, tidal volume, airflow rate), inflammatory cytokines (interleukin [IL]-4, IL-5, IL-13), total and differential leukocytes in blood as well as bronchoalveolar lavage fluid (BALf) and histological examinations. The computational study indicated that TLR4 antagonist activity of soya PC is due to linoleic acid (18:2) fatty acid chain. Soya PC significantly suppressed the LPS-induced neutrophil adhesion in a concentration-dependent manner to 1 µg/mL. The treatment of soya PC (5 and 10 mg/kg, 18 days, i.p.) significantly improved the lung function parameters, total and differential leukocyte counts in blood and BALf in asthmatic rats. This efficacy of soya PC was in extent similar to dexamethasone (2.5 mg/kg, 18 days, i.p.). However, soya PC was superior to dexamethasone in terms of benefits. The protective action of soya PC may be due to TLR4 antagonist activity and linoleic acid composition.