Neuroprotection of the P2X7 receptor antagonist A740003 on retinal ganglion cells in experimental glaucoma.

The aim of this study was to explore the neuroprotective effects of the P2X7 receptor antagonist A740003 on retinal ganglion cells (RGCs) in chronic intraocular hypertension (COH) experimental glaucoma mouse model. Bioinformatics was used to analyze the glaucoma-related genes. Western blot, real-time fluorescence quantitative PCR, and immunofluorescence staining techniques were employed to explore the mechanisms underlying the neuroprotective effects of A740003 on RGCs in COH retinas. Bioinformatic analysis revealed that oxidative stress, neuroinflammation, and cell apoptosis were highly related to the pathogenesis of glaucoma. In COH retinas, intraocular pressure elevation significantly increased the levels of translocator protein, a marker of microglial activation, which could be reversed by intravitreal preinjection of A740003. A740003 also suppressed the increased mRNA levels of proinflammatory cytokines interleukin (IL) 1ß and tumor necrosis factor α in COH retinas. In addition, although the mRNA levels of anti-inflammatory cytokine IL-4 and IL-10 were kept unchanged in COH retinas, administration of A740003 could increase their levels. The mRNA and protein levels of Bax and cleaved caspase-3 were increased in COH retinas, which could be partially reversed by A740003, while the levels of Bcl-2 kept unchanged in COH retinas with or without the injections of A740003. Furthermore, A740003 partially attenuated the reduction in the numbers of Brn-3a-positive RGCs in COH mice. A740003 could provide neuroprotective roles on RGCs by inhibiting the microglia activation, attenuating the retinal inflammatory response, reducing the apoptosis of RGCs, and enhancing the survival of RGCs in COH experimental glaucoma.

Development and characterization of an α-l-rhamnosidase mutant with improved thermostability and a higher efficiency for debittering orange juice.

The glycoside hydrolase, α-l-rhamnosidase, could remove the bitter taste of naringin from citrus juices. However, most α-l-rhamnosidases are easily deactivated at high temperatures, limiting the practice in debittering citrus juices. The V529A mutant of the α-l-rhamnosidase r-Rha1 from Aspergillus niger JMU-TS528 was developed with improved thermostability using directed evolution technology and site-directed mutagenesis. The enzyme mutant had a half-live of thermal inactivation T(1/2) of 1.92 h, 25.00 min, and 2 min at 60, 65, and 70 °C, respectively. In addition, it had improved substrate affinity and better resistance to the inhibition of glucose. The improved substrate affinity was related to its lowered binding energy. Most significantly, the naringin content was reduced to below the bitter taste threshold by treatment with 75 U/mL of the mutant during the preheating process of orange juice production. The comprehensive results indicate that thermostability improvement could promote the practical value of α-l-rhamnosidase in citrus juice processing.

[Human chorionic gonadotrophin on the expression of epidermal growth factor in rat renal tissues].

AIM: To investigate hCG on the expression of epidermal growth factor (EGF) in renal tissues. METHODS: 20 male SD rats weighed 300 - 350 g were injected hCG 200 IU/d for 7 days, and 20 male rats were injected sa-line at equal volume as a control. Kidney tissues were per-formed with immunohistochemical staining to evaluate the distribution of EGF and quantitative PCR (Q-PCR) was used to evaluate the EGF mRNA. RESULTS: Immunohistochemtry showed that the positive rate of EGF in experimental group was significantly higher than that in control group(P<0.01), but Q-PCR results showed no significant difference between two groups ( P > 0. 05). CONCLUSION: hCG increased the concentration of EGF by maturing pre-pro-EGF not expressing EGF from de novo synthesis.