Protective effect of excretory-secretory proteins from Trichinella spiralis muscle larvae against myocardial injury in septic mice / 南方医科大学学报

OBJECTIVE@#To evaluate the protective effect of excretory-secretory proteins from Trichinella spiralis muscle larvae (Ts-MES) on sepsis-induced myocardial injury in mice.@*METHODS@#Eighty male BALB/C mice were randomized equally into sham-operated group, myocardial injury group, Ts-MES treatment group and dexamethasone treatment group. In the latter 3 groups, sepsis-induced myocardial injury models were established by cecal ligation and perforation; the sham operation was performed by exposure of the cecum without ligation or perforation. Forty minutes after the operation, the mice were given intraperitoneal injections 150 μL PBS, 20 μg TS-MES or 0.3 mg/kg dexamethasone as indicated. At 12 h after the operation, 6 mice were randomly selected from each group for echocardiography, and 8 mice were used for observing the survival rate within 72 h. The remaining 6 mice were examined for myocardial pathologies with HE staining and serum levels of NTPro-BNP and cTnI with ELISA; the expressions of TNF-α, IL-6, IL-10 and TGF-β in the serum and myocardial tissue were detected using ELISA and qRT-PCR.@*RESULTS@#Compared with the sham-operated mice, the septic mice showed significantly decreased cardiac function indexes (LVEF, LVFS, and E/A) with lowered survival rate within 72 h (P < 0.001) and significantly higher myocardial injury scores and serum levels of NTPro-BNP and cTnI (P < 0.01). Treatment with TS-MES significantly improved the cardiac function and 72-h survival rate (P < 0.05) and lowered the myocardial injury scores and serum levels of NTPro-BNP and cTnI (P < 0.05) in the septic mice. Compared with the sham-operated mice, the septic mice had obviously increased TNF-α and IL-6 levels in the serum and myocardial tissue (P < 0.001), which were significantly lowered by treatment with TS-MES (P < 0.05). TS-MES and dexamethasone both increased the levels of IL-10 and TGF-β in the septic mice, but the changes were significant only in TS-MES-treated mice (P < 0.05).@*CONCLUSION@#Ts-MES are capable of protecting against myocardial injury in septic mice by reducing the production of pro-inflammatory cytokines and enhancing the levels of regulatory cytokines.

Protective effect of excretory-secretory protein from adult Trichinella spiralis on ovalbumin-induced allergic rhinitis in mice / 中国血吸虫病防治杂志

Objective To investigate the protective effect of excretory-secretory protein (AES) from adult Trichinella spiralis on ovalbumin (OVA)-induced allergic rhinitis in mice. Methods Eighteen female BALB/c mice were randomly divided into three groups, including the blank control group (Group A), OVA-induced rhinitis group (Group B) and AES treatment group (Group C). Mice in Group A were given PBS. Mice in Group B were intraperitoneally injected with antigen adjuvant suspension for systemic sensitization, once every other day for seven times; then, local excitation was intranasally induced with 5% OVA solution once a day for seven times to establish a mouse model of allergic rhinitis. In addition to induction of allergic rhinitis, mice in Group C were given 25 μg AES at baseline sensitization and local excitation. Following the final challenge, mice were observed for 30 min in each group, and the behavioral score was evaluated. The serum levels of IFN-γ, IL-4, IL-5, IL-10 and TGF-β were determined using an enzyme-linked immunosorbent assay in mice, and the pathological changes of mouse nasal mucosa were observed under a microscope. Results There was a significant difference in the mouse behavioral scores among the three groups (F = 110.12, P < 0.01). The mouse behavioral score was significantly higher in Group B than in Group A (7.17 ± 0.75 vs. 1.33 ± 0.52, P < 0.01), and more remarkable pathological damages of mouse nasal mucosa were seen in Group B than in Group A, while the mouse behavioral score was significantly decreased in Group C than in Group B (P < 0.01), and the pathological damages of mouse nasal mucosa remarkably alleviated in Group C relative to Group B. There was a significant difference in serum IFN-γ level among the three groups (F = 7.50, P < 0.01) and the serum IFN-γ level in Group B was significantly lower than in group A and C (both P < 0.05). There were significant differences in serum IL-4 (F = 470.81, P < 0.01) and IL-5 levels (F =68.20, P < 0.01) among the three groups, and significantly greater serum IL-4 and IL-5 levels were detected in Group B than in Group A (P < 0.01), while significantly lower serum IL-4 and IL-5 levels were detected in Group C than in Group B (P < 0.01). There were significant differences in serum IL-10 (F = 174.91, P < 0.01) and TGF-β levels (F = 9.39, P < 0.01) among the three groups, and significantly greater serum IL-10 and TGF-β levels were seen in Group C than in Group B (both P < 0.05). Conclusion T. spiralis AES has a remarkable protective activity against OVA-induced allergic rhinitis in mice.

Protective effect of excretory-secretory protein from adult Trichinella spiralis on ovalbumin-induced allergic rhinitis in mice / 中国血吸虫病防治杂志

Objective To investigate the protective effect of excretory-secretory protein (AES) from adult Trichinella spiralis on ovalbumin (OVA)-induced allergic rhinitis in mice. Methods Eighteen female BALB/c mice were randomly divided into three groups, including the blank control group (Group A), OVA-induced rhinitis group (Group B) and AES treatment group (Group C). Mice in Group A were given PBS. Mice in Group B were intraperitoneally injected with antigen adjuvant suspension for systemic sensitization, once every other day for seven times; then, local excitation was intranasally induced with 5% OVA solution once a day for seven times to establish a mouse model of allergic rhinitis. In addition to induction of allergic rhinitis, mice in Group C were given 25 μg AES at baseline sensitization and local excitation. Following the final challenge, mice were observed for 30 min in each group, and the behavioral score was evaluated. The serum levels of IFN-γ, IL-4, IL-5, IL-10 and TGF-β were determined using an enzyme-linked immunosorbent assay in mice, and the pathological changes of mouse nasal mucosa were observed under a microscope. Results There was a significant difference in the mouse behavioral scores among the three groups (F = 110.12, P < 0.01). The mouse behavioral score was significantly higher in Group B than in Group A (7.17 ± 0.75 vs. 1.33 ± 0.52, P < 0.01), and more remarkable pathological damages of mouse nasal mucosa were seen in Group B than in Group A, while the mouse behavioral score was significantly decreased in Group C than in Group B (P < 0.01), and the pathological damages of mouse nasal mucosa remarkably alleviated in Group C relative to Group B. There was a significant difference in serum IFN-γ level among the three groups (F = 7.50, P < 0.01) and the serum IFN-γ level in Group B was significantly lower than in group A and C (both P < 0.05). There were significant differences in serum IL-4 (F = 470.81, P < 0.01) and IL-5 levels (F =68.20, P < 0.01) among the three groups, and significantly greater serum IL-4 and IL-5 levels were detected in Group B than in Group A (P < 0.01), while significantly lower serum IL-4 and IL-5 levels were detected in Group C than in Group B (P < 0.01). There were significant differences in serum IL-10 (F = 174.91, P < 0.01) and TGF-β levels (F = 9.39, P < 0.01) among the three groups, and significantly greater serum IL-10 and TGF-β levels were seen in Group C than in Group B (both P < 0.05). Conclusion T. spiralis AES has a remarkable protective activity against OVA-induced allergic rhinitis in mice.

Molecular cloning of a rhoptry protein (ROP6) secreted from Toxoplasma gondii

Monoclonal antibody (mAb) Tg786 against Toxoplasma gondii has been found to detect a 42-kDa rhoptry protein (ROP6) which showed protease activity and host cell binding characteristics after secretion. Using the mAb, a colony containing a 3'-UTR was probed in a T. gondii cDNA expression library. A full length cDNA sequence of the rhoptry protein was completed after 5'-RACE, which consisted of 1,908 bp with a 1,443 bp ORF. The deduced amino acid sequence of ROP6 consisted of a polypeptide of 480 amino acids without significant homology to any other known proteins. This sequence contains an amino terminal stop transfer sequence downstream of a short neutral sequence, hydrophilic middle sequence, and hydrophobic carboxy terminus. It is suggested that the ROP6 is inserted into the rhoptry membrane with both N- and C-termini.

Protease activity of 80 kDa protein secreted from the apicomplexan parasite Toxoplasma gondii

This study describes the characterization of 80 kDa protease showing gelationlytic property among three proteases in the excretory/secretory proteins (ESP) from Toxoplasma gondii. The protease activity was detected in the ESP but not in the somatic extract of RH tachyzoites. This protease was active only in the presence of calcium ion but not other divalent cationic ions such as Cu (2+), Zn (2+), Mg (2+), and Mn (2+), implying that Ca (2+) is critical factor for the activation of the protease. The 80 kDa protease was optimally active at pH 7.5. Its gelatinolytic activity was maximal at 37 degrees C, and significant level of enzyme activity of the protease remained after heat treatment at 56 degrees C for 30 min or 100 degrees C for 10 min. This thermostable enzyme was strongly inhibited by metal chelators, i.e., EDTA, EGTA, and 1, 10-phenanthroline. Thus, the 80 kDa protease in the ESP secreted by T. gondii was classified as a calcium dependent neutral metalloprotease.