Glaucocalyxin A attenuates allergic responses by inhibiting mast cell degranulation through HMGB1/TLR4/NF-κB signaling pathways / 药学学报

The study is to investigate the effect of glaucocalyxin A (GLA) on mast cell-mediated anaphylaxis. The animal welfare and experimental process of this experiment followed the regulations of the Animal Ethics Committee of Yanbian University. BALB/c mice were used in the animal experiment and randomly divided into five groups, control group, model group, and GLA low, medium, and high dose groups (10, 20, and 40 mg·kg-1). Mice were sensitized by intradermal injection of anti-dinitrophenyl-immunoglobulin E (DNP-IgE) into the ears and challenged with a mixture of DNP-human serum albumin (HSA) and 4% evans blue into the tail veins to prepare an animal skin passive cutaneous anaphylaxis (PCA) model, which was collected from both ears for measurement of dye staining and histology. Rat peritoneal mast cells (RPMCs) were used in the cell experiment and divided into control, IgE + antigen (Ag), and IgE + Ag + GLA groups to determine histamine release as well as calcium influx levels. High-affinity IgE receptor (FcεRI)-mediated signaling pathway proteins and HMGB1/TLR4/NF-κB (high mobility group box 1/toll like receptor 4/nuclear transcription factor kappa B) signaling proteins were detected by Western blot. The results of animal experiments suggest that GLA inhibits PCA, reduces evans blue dye exudation, and reduces ear inflammation and ear thickness in mice. The results of cellular experiments suggested that GLA could reduce histamine release and calcium influx, and inhibit tumor necrosis factor-α (TNF-α), interleukin (IL)-4, IL-13, and IL-1β production; Western blot results showed that GLA inhibited FcεRI-mediated phosphorylation levels of spleen tyrosine kinase (Syk), Lck/Yes novel tyrosine kinase (Lyn), tyrosine kinase Fyn (Fyn), growth-factor receptor-bound protein 2 (Gab2), and phospholipase C (PLC) γ1, while GLA inhibited HMGB1/TLR4 signaling pathway to limit NF-κB p65 nuclear metastasis. The results indicate that GLA inhibits mast cell degranulation and attenuates allergic inflammation through the HMGB1/TLR4/NF-κB signaling pathway.

Polydatin attenuates airway inflammation in asthmatic mouse model via p38 MAPK/Nrf2/HO-1 pathway / 中国药理学通报

Aim To investigate whether polydatin re-duces airway inflammation in asthmatic mouse model and explore whether this pathway is related to p38 MAPK/Nrf2/HO-1 . Methods After the establish-ment of the OVA-induced asthmatic mouse model, the animals were injected with 30 mg·kg-1 and 45 mg· kg-1 of polydatin diluted in 0. 2 mL normal saline, while the control group was replaced by normal saline. HE, PAS and Masson staining were used to observe the pathological changes of lung tissue. Diff-Quick staining was used to classify and count the number of inflamma-tory cells in BALF. ELISA was used to detect IgE ex-pressions in BALF. The content of ROS in BALF cells was detected by DHR-123 . The activities of antioxidant enzymes SOD, CAT and MDA in BALF were detected by the enzyme-linked immunosorbent assay kit. The expression of HO-1 in lung tissue was detected by im-munohistochemistry. The protein and mRNA expres-sions of Nrf2 and HO-1 in lung tissue of mice were de-tected by Western blot and RT-PCR. Results Poly-datin treatment significantly reduced inflammatory cell infiltration mucosal secretion, goblet cell proliferation and collagen deposition in the lung tissue of mice, and decreased the number of inflammatory cells and the ex-pression of total IgE and ROS in BALF. It also in-creased the levels of antioxidant enzymes such as SOD and CAT, and lowered the level of MDA. Polydatin re-duced the phosphorylation of p38 MAPK in the lung tissue of mice, enhanced the levels of mRNA and pro-tein expressions of Nrf2 and HO-1 and promoted the nuclear transfer of Nrf2 . The above effects of polydatin were dose-dependent. Conclusions Polydatin exerts anti-oxidative effects in OVA-induced asthmatic mouse model via anti-oxidant pathway. The mechanism may be achieved through the p38 MAPK/Nrf2/HO-1 path-way.

Sesamin suppresses mast cell activation through inhibition of PKCα/NF-κB signaling pathway / 中国免疫学杂志

Objective:To investigate the effect of sesamin on mast cell activation and its inflammatory mediator release,as well as its possible mechanisms of action.Methods:HCM-1 cells were activation by stimulation with 10 μg/ml anti-DNP IgE for 6 h and challenge with 100 ng/ml DNP-HAS for 10 min.Sesamin was administration at the concentration of 25,50 and 100 μg/L prior to DNP-HAS challenge,subsequently the effect of sesamin on mast cell degranulation was investigated by light microscope,and histamine release and expression of cytokines such as TNF-α IL-6,IL-1β,IL-8 of mast cells after sesamin treatment were investigated by ELISA.Western blot was used to determine the effect of sesamin on FcεRI downstream signaling including Lyn,Syk and PKCα activation,and IκBα phosphorylation and NF-κB activation.Results:DNP-HAS significantly increased mast cell degranulation,histamine release and those cytokines expression,enhanced Lyn,Syk,PKCα,IκBα phosphorylation and NF-κB activation(P<0.05). Sesamin(50,100 μg/L) significantly decreased mast cell degranulation,histamine release and cytokines expression (TNF-α,IL-4,IL-1β,and IL-8),reduced activity of Lyn,Syk,kinases and PKCα and IκBα phosphorylation,and inhibited NF-κB activation(P<0.05).Conclusion: Sesamin suppresses mast cell activation and inflammatory mediators release through inhibition of PKCα/NF-κB signaling pathway.

Forskolin inhibits spontaneous contraction of gastric antral smooth muscle in rats / 生理学报

The aim of the present study was to investigate the effects of cyclic adenosine monophosphate (cAMP) on rat gastric antral circular smooth muscle function. Forskolin, a direct activator of adenylyl cyclase (AC), was used to observe the influences of cAMP. Multi-channel physiological recorder was used to record spontaneous contraction activity of gastric antral circular muscle from Wistar rats. And ELISA method was used to detect the change of cAMP production in perfusate. The results showed that forskolin concentration-dependently suppressed the amplitude and frequency of the spontaneous contraction of the gastric antral muscle, and lowered the baseline of contraction movement significantly. Forskolin concentration-dependently increased the production of cAMP in the perfusate, which showed a significant negative correlation with the contraction amplitude of gastric antral ring muscle. The inhibitory effect of forskolin on spontaneous contraction activity of rat gastric antral circular muscle could be blocked by cAMP-dependent protein kinase (PKA) inhibitor H-89. These results suggest forskolin increases cAMP production and then activates PKA pathway, resulting in the inhibition of the spontaneous contraction activity of rat gastric antral circular smooth muscle.