RESUMO
The extracellular superoxide dismutases (ecSODs) secreted by Microplitis bicoloratus reduce the reactive oxygen species (ROS) stimulated by the Microplitis bicoloratus bracovirus. Here, we demonstrate that the bacterial transferase hexapeptide (hexapep) motif and bacterial-immunoglobulin-like (BIg-like) domain of ecSODs bind to the cell membrane and transiently open hemichannels, facilitating ROS reductions. RNAi-mediated ecSOD silencing in vivo elevated ROS in host hemocytes, impairing parasitoid larva development. In vitro, the ecSOD-monopolymer needed to be membrane bound to open hemichannels. Furthermore, the hexapep motif in the beta-sandwich of ecSOD49 and ecSOD58, and BIg-like domain in the signal peptides of ecSOD67 were required for cell membrane binding. Hexapep motif and BIg-like domain deletions induced ecSODs loss of adhesion and ROS reduction failure. The hexapep motif and BIg-like domain mediated ecSOD binding via upregulating innexins and stabilizing the opened hemichannels. Our findings reveal a mechanism through which ecSOD reduces ROS, which may aid in developing anti-redox therapy.
RESUMO
The aim of the study was to explore the effect of birdpecking and revolving moxibustion on twelve back shenshu points on the bone metabolism and bone histomorphometry of osteoporosis rats. The 50 female rats of 8 months old that did not pregnant were collected and randomly divided into sham-operation group, model group, moxibustion group, moxibustion and estrogen group, and estrogen group. All the rats, except for the rats in the sham-operation group, received ovarian surgery to establish the models. After 10 days postoperatively (healing), the rats received moxibustion and estrogen therapy. According to the different groups, the rats received rat femur in vivo bone mineral density assessment at 90 days after surgery. After that, the rats were sacrificed, and then the left femoral bones were collected for bone histomorphometry test; blood was taken for bone alkaline phosphatase (BALP) testing, and urine was collected for hydroxyproline testing. The urine hydroxyproline was tested once at 24 h after ovarian surgery. At 24 h after ovarian surgery, the urine hydroxyproline in the ovariectomy group was significantly higher than that in the sham-operation group (P < 0.05), indicating that after ovarian surgery, the collagen broke down which accelerated the process of osteoporosis. After the intervention therapy with moxibustion and estrogen, the BALP, urinary hydroxyproline and femoral bone histomorphometry were comparatively analyzed, and the results showed that the intervention groups were higher than the model group (P < 0.05). But when compared with the sham-operation group, the indexes in the intervention groups were decreased, and the differences were significant (P < 0.05), indicating that intervention could only delay the incidence of osteoporosis. The Chinese traditional measure of "birdpecking and revolving moxibustion on twelve back-shu points" can effectively prevent the recession of bone metabolism of osteoporosis rats, and slow down the degeneration of bone morphology, which can be used to delay the incidence of osteoporosis.
