A protective role of Gαq-RGS2 loop activator on streptozotocin induced diabetic complications in rats: An independent on elevated serum glucose level modulation

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.

Acute and 28-days subacute toxicity studies of Gαq-RGS2 signaling inhibitor

Background

The aim of study was to evaluate the single oral dose and 28 day repeated oral administration toxicity profile of the synthetic compound Gαq-RGS2 signaling inhibitor, (1-(5-chloro-2-hydroxyphenyl)-3-(4-(trifluoromethyl)phenyl)-1 H-1,2,4-triazol-5(4 H)-one) as per OECD guideline 425 (2008a) and 407 (2008b), respectively.

Results

In acute toxicity study, a single oral dose administration of Gαq-RGS2 signaling inhibitor did not show any mortality at doses of 5, 50, 300 and 2000 mg/kg within 24 h and 14 days. The treatment of Gαq-RGS2 signaling inhibitor at dose 10 and 100 mg/kg for 28 days did not show any mortality, significant changes in the increase of body weight, various organ damage markers, hematological parameters, relative organ/body weight ratio and microscopic anatomical texture of essential organs as compared to vehicle and normal control.

Conclusions

A single oral administration of Gαq-RGS2 signaling inhibitor up to dose of 2000 mg/kg in mice and repeated administration of Gαq-RGS2 signaling inhibitor at higher dose 100 mg/kg for 28 days in the rats is safe.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42826-021-00093-1.

Berberis kansuensis extract alleviates type 2 diabetes in rats by regulating gut microbiota composition

BACKGROUND

The stem bark of Berberis kansuensis Schneid (BK) is a commonly used Tibetan medicine for the treatment of type 2 diabetes (T2D). However, its therapeutic mechanisms remain unclear.

AIM OF THE STUDY

Our aim is to clarify the role of gut microbiota in the anti-diabetic activity of BK extract.

MATERIALS AND METHODS

High fat diet combined with low-dose streptozotocin (45 mg/kg) was used to establish a T2D rat model, and the body weight of rats was measured every five days. Fasting blood glucose (FBG), glycosylated serum protein (GSP), insulin resistance index (HOMA-IR), insulin sensitivity index (ISI), lipopolysaccharide (LPS), and three inflammatory factors (TNF-α, IL-1 β and IL-6) were measured to evaluate the anti-diabetic activity of BK. Moreover, pseudo-germ-free animals were prepared by oral administration of an antibiotic mixture (100 mg/kg neomycin, 100 mg/kg ampicillin and 50 mg/kg metronidazole) twice per day for 6 days to assess the role of gut microbiota. Gut microbiota analysis was performed through 16S rRNA high-throughput sequencing method.

RESULTS

After 30 days of administration, BK extract could significantly decrease the levels of body weight, FBG, GSP, HOMA-IR, LPS, TNF-α, IL-1β and IL-6, and increase ISI levels in T2D rats. However, when the gut microbiota of T2D rats was disturbed by antibiotics, BK could not improve HOMA-IR and ISI levels in T2D rats. The results indicated that the anti-diabetic effect of BK might depend on the gut microbiota. Moreover, sequencing of 16S rRNA genes demonstrated that BK could significantly improve the gut microbiota disorder of T2D rats. Specifically, BK increased the abundance of phyla Bacteroidetes and genera Akkermansia and the ratio of Bacteroides/Firmicutes, while reducing the abundance of phyla Proteobacteria and genera Collinella, [Ruminococcus]_gauvreauii_Group, Escherichia Shigella, Enterococcus, Fusobacterium, Holdemanella, and Prevotella_9 in T2D rats. Additionally, correlation analysis revealed that Akkermansia was positively correlated with ISI, while [Ruminococcus]_gauvreauii_Group, Collinella, Escherichia Shigella, Enterococcus, Fusobacterium, Holdemanella and Prevotella_9 were positively correlated with FBG, GSP, LPS, HOMA-IR, TNF-α, IL-1β, and IL-6.

CONCLUSION

BK extract has a good anti-diabetic effect on T2D rats. The mechanism by which this extract exerts its action is, at least partly, related to its regulation of gut microbiota.

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 7^th, 14^th, 21^st 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.

Protective effects of Gαq-RGS2 signalling inhibitor in aminophylline induced cardiac arrhythmia

An over activation of GPCR mediated Gαq dependent signalling pathway is widely associated with the development of cardiovascular abnormalities. The objective of study was to evaluate the effects of (1-(5-chloro-2-hydroxyphenyl)-3-(4-(trifluoromethyl)phenyl)-1H-1,2,4-triazol-5(4H)-one) Gαq-RGS2 signalling inhibitor on aminophylline induced cardiac arrhythmia in rats. Rats were divided into four groups; normal rats, disease control (DC, aminophylline treated 100 mg/kg/d, i.p., 7 days), Gαq-RGS2 signalling inhibitor (1 and 10 mg/kg/d, p.o., 7 days) treated arrhythmic rats. Gαq-RGS2 signalling inhibitor was administered 1 hour prior to the administration of aminophylline from 1st day. At the end of study, heart rate (HR), QRS complex, QT and RR interval were measured by electrocardiogram (ECG) of anesthetized rats. Systolic and diastolic blood pressure (SBP, DBP) by invasive method, cardiac damage markers (CK-MB, LDH) in the serum, antioxidant enzymes (SOD, catalase, glutathione) and cAMP level were measured. The treatment of Gαq-RGS2 signalling inhibitor (10 mg/kg) significantly abolished the aminophylline induced increase of heart rate, prolongation of RR and QT interval as compared to DC rats. Gαq-RGS2 signalling inhibitor (1 and 10 mg/kg) significantly attenuated the prolongation in QRS complex, increase of SBP, DBP and cardiac damage markers as compared to DC. Gαq-RGS2 signalling inhibitor treatment (10 mg/kg) significantly reduced the cAMP level and increased the antioxidant enzyme level as compared to DC. Gαq-RGS2 signalling inhibitor (10 mg/kg) showed the protective effect against the aminophylline induced cardiac arrhythmia and it might be due to improvement in cAMP level and antioxidant enzymes.

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.