Effect of Lycium barbarum Polysaccharides on the expression of endothelin-1 and its receptors in an ocular hypertension model of rat glaucoma

Lycium barbarum, a traditional Chinese anti-aging herb, has been shown to protect retinal ganglion cells (RGCs) in a rat chronic ocular hypertension (COH) model. Here, we investigated the expression of endothelin-1 (ET-1), a strong vasoconstrictor, and its receptors, ETA and ETB, in the COH model and assessed the effects of Lycium barbarum on the ET-1 axis. Elevated intraocular pressure (IOP) was induced in the right eye of SD rats using argon laser photocoagulation. (1) The expression of ET-1, ETA and ETB in normal and COH retinas was studied. (2) Some COH rats were fed daily with Lycium barbarum Polysaccharides (LBP) using 1 mg/kg or phosphate-buffered saline (PBS) for 3 weeks (started 1 week before photocoagulation). The effects of LBP on the expression of ET-1 and its receptors, ETA and ETB, in COH retina were evaluated. A semi-quantitative analysis of staining intensity was used to evaluate the expression levels of ET-1, ETA and ETB in retinal vasculature. We found that (1) Under COH condition, the immunoreactivity of ET-1 was increased in retina associated with an increase of ETB receptor immunoreactivity and a decrease of ETA receptor immunoreactivity. (2) After feeding COH rats with LBP, the expression of ET-1 was decreased with an increase of ETA expression and a decrease of ETB expression in the retina, especially in RGCs. (3) By comparing the staining intensity in the vasculature of COH retina in LBP-fed group with PBS-fed group, there was a decrease in the expression of ET-1 and ETA and an increase in ETB. In summary, ET-1 expression was up-regulated in the retina in COH model. LBP could decrease the expression of ET-1 and modulate the expression of its receptors, ETA and ETB, under the condition of COH. The neuroprotective effect of LBP on RGCs might be related to its ability to regulate the ET-1-mediated biological effects on RGCs and retinal vasculature.     

Screening and identification of dietary oils and unsaturated fatty acids in inhibiting inflammatory prostaglandin E

ABSTRACT: BACKGROUND: The molecular mechanisms of dietary oils (such as fish oil) and unsaturated fatty acids, which are widely used by the public for anti-inflammation and vascular protection, have not been settled yet. In this study, prostaglandin E2 (PGE2)-mediated calcium signaling was used to screen dietary oils and eight unsaturated fatty acids for identification of their anti-inflammatory mechanisms. Isolated fat/stromal cells expressing endogenous PGE2 receptors and an HEK293 cell line specifically expressing the recombinant human PGE2 receptor subtype-1 (EP1) were cultured and used in live cell calcium signaling assays. The different dietary oils and unsaturated fatty acids were used to affect cell signaling under the specific stimulation of a pathological amount of inflammatory PGE2. RESULTS: It was identified that fish oil best inhibited the PGE2 signaling in the primary cultured stromal cells. Second, docosahexaenoic acid (DHA), found in abundance in fish oil, was identified as a key factor of inhibition of PGE2 signaling. Eicosapentaenoic acid (EPA), another major fatty acid found in fish oil and tested in this study was found to have small effect on EP1 signaling. The study suggested one of the four PGE2 subtype receptors, EP1 as the key target for the fish oil and DHA target. These findings were further confirmed by using the recombinant EP1 expressed in HEK293 cells as a target. CONCLUSION: This study demonstrated the new mechanism behind the positive effects of dietary fish oils in inhibiting inflammation originates from the rich concentration of DHA, which can directly inhibit the inflammatory EP1-mediated PGE2 receptor signaling, and that the inflammatory response stimulated by PGE2 in the fat stromal cells, which directly related to metabolic diseases, could be down regulated by fish oil and DHA. These findings also provided direct evidence to support the use of dietary oils and unsaturated fatty acids for protection against heart disease, pain, and cancer resulted from inflammatory PGE2.     

Isolation and characterisation of microsatellite loci in the tire track eel,Mastacembelus favus and cross-species amplification

Nine microsatellite loci were isolated and characterized in the tire track eel, Mastacembelus favus by using library enriched for microsatellite region. Among 47 specimens collected from Mekong River, the number of alleles ranged from 2 to 17 while levels of observed and expected heterozygosities ranged from 0.021 to 0.873 and from 0.021 to 0.893, respectively. The primers were successfully tested in six closely related species, hence valuable for investigating population genetics and other related aspects of M. favus and its congener species.