Spirulina (SP) (Arthrospira platensis; previously Spirulina platensis) is a filamentous blue-green microalga (cyanobacterium) with potent dietary phytoantioxidant and anticancerous properties. We investigated the chemopreventive effect of SP against 7,12-dimethylbenz[a]anthracene (DMBA)-induced rat breast carcinogenesis, and further studied its underlying mechanisms of action in vitro. Remarkably, SP cleared DMBA-induced rat mammary tumors, which was clearly confirmed by morphological and histological methods. SP supplementation reduced the incidence of breast tumors from 87% to 13%. At the molecular level, immunohistochemical analysis revealed that SP supplementation reduced expression of both Ki-67 and estrogen α. More interestingly, molecular analysis in the in vitro experiments indicated that SP treatment inhibited cell proliferation by 24 hours, which was accompanied by increased p53 expression, followed by increased expression of its downstream target gene, Cdkn1a (alias p21 or p21(Waf1/Cip1)). In addition, SP increased Bax and decreased Bcl-2 expression, indicating induction of apoptosis by 48 hours after SP treatment. To our knowledge, this is the first report of in vivo chemopreventive effect of SP against DMBA-induced breast carcinogenesis in rat, supporting its potential use in chemoprevention of cancer.
Although the current treatment of schistosomiasis relies largely on praziquantel (PZQ), it has not been successful in significantly reducing the overall rate of disease cases, one of the suggested reasons being the inevitable resistance to PZQ. Previous studies showed that radiation-attenuated vaccine provides protection against Schistosoma mansoni in a host of various species. In the present study, we evaluated the effect of various vaccination strategies in C57BL/6 mice, including single or multiple vaccination strategy, subcurative dose (20 mg/kg) of PZQ, and a combination of single vaccination with subcurative dose of PZQ. Treatment either with subcurative dose of PZQ or with a single vaccination of attenuated cercariae (500 per mouse), caused significant reduction in total worm burden, hepatic, and intestinal ova counts of 43.03, 73.2, and 59.5 and 37.97, 52.02, and 26.3%, respectively. Furthermore, tegumental changes were observed. In multiple vaccinated group, there was an extensive lysis in tegumental layers. High deformations in gastrodermis, testis cells, vitelline cells, and oocytes were recorded. Also, this study is to explore the role of humoral immunity using highly resistant rabbits that had been exposed to three immunizations with ultraviolet (UV)-irradiated cercariae (8000 per rabbit in each immunization), and their sera were tested for their ability to transfer protection. The reduction in challenge worm burden had reached 32.76-43.64% when compared with recipients of normal serum or no serum. The reduction in hepatic and intestinal ova counts reached to 74.4 and 71.08% in group immunized with vaccinated rabbit sera. Swelling and extensive lysis of tegumental layers, gastrodermis lumen, spermatocytes, and deformation of oocytes were recorded with more severity than that recorded in normal rabbit sera group. Our findings recorded that multiple vaccination strategy is the most effective strategy then passive transfer of vaccinated rabbit. This gives guiding in the design the appropriate therapeutic strategy.
Although the current treatment of schistosomiasis relies largely on praziquantel (PZQ), it has not significantly reduced the overall number of disease cases, perhaps due to inevitable resistance to PZQ. Previous studies showed that radiation-attenuated vaccine gives protection levels for Schistosoma mansoni in host various species. In the present study, we evaluated the effect of various vaccination strategies in C57BL/6 mice, including single or multiple vaccination strategy, subcurative dose (20 mg/kg) of PZQ, and a combination of single vaccination with subcurative dose of PZQ. Groups of five mice were sacrificed postinfection in 42 days and schistosomes were collected by perfusion and examined by scanning electron microscopy. Treatment either with subcurative dose of PZQ or with a single vaccination of attenuated cercariae (500 per mouse), caused significant reduction in total worm burden, hepatic and intestinal ova counts 43.03%, 73.2%, 59.5% and 37.97%, 52.02%, 26.3%, respectively. Furthermore, tegumental changes were observed, including severe swelling, fusion of tegumental folds, vesicle formation, and loss or shortening of the spines on the tubercles. However, multiple vaccination strategy resulted in much higher reduction in total worm burden, hepatic and intestinal ova count. However, multiple vaccination strategy resulted in high reduction of worm burden, hepatic and intestinal ova counts 72.5%, 90.7%, 65.79%, respectively, and further causing swollen, disruption of tubercles teguments and erosion, extensive peeling, fusion of tegumental folds. Our findings suggest that multiple vaccination strategy is the most effective strategy to clear schistosomal infection, indicating its potential in guiding the design of appropriate therapeutic strategy against schistosomes.
The purpose of the study is to explore the role of humoral immunity against Schistosoma mansoni infection in C57BL/6 mice using highly resistant rabbits that had been exposed to three separate immunizations with ultraviolet (UV)-irradiated cercariae (8,000 attenuated cercariae/rabbit in each immunization), and their sera were tested for their ability to transfer protection against S. mansoni challenge. The present study showed the reduction in challenge worm burden had reached 32.76-43.64% when compared with recipients of normal serum or no serum. The surface topography of the worms collected from immunized mice with either normal rabbit sera (NRS) or vaccinated rabbit sera (VRS) revealed severe tegumental alterations, especially in the VRS group. Worms collected from groups that were immunized by NRS or VRS postinfection (200 normal cercariae/mouse) by day 42. Worms from group immunized with NRS showed damage in the tegument, characterized by severe swelling or erosion of tegumental folds, accompanied by changes in tubercles, swelling, shortening, and loss of spines in male worms. The alteration in female tegument was characterized by swelling of tegumental folds, atrophy of ventral sucker, damage of sensory papillae along all the body, severe peeling in some regions, and appearance of few small blebs. VRS induced more severe tegumental damage than NRS in both male and female worms. Severe shrunken vesicles were protruded from the surface between the two suckers. The tegument of the male showed a collapse of tubercles followed by the appearance of vesicles on their surfaces, fusion, erosion, and superficial focal peeling of tegumental folds. In the female worms, severe damage to the oral sucker, the surface between the two suckers, extensive peeling, severe swelling of the tegument, and damage of sensory papillae. In conclusion, the present study support the hypothesis that high levels of antibodies were developed in rabbit sera after multiple exposures to attenuated cercariae of S. mansoni. Furthermore, immunization might have transferred protection against the infection, indicated by severe morphological alterations, a sign of elimination of the worms. Further investigation is being carried out to reveal the molecular mechanisms underlying the transfer of protection.
Background: The utilization of stem cell trans-differentiation into insulin-producing cells (IPCs) would provide potential promising therapy for diabetes mellitus (DM). Objective: The study was aimed to investigate the differentiation potential of rabbit's bone marrowderived cells into insulin producing cells. Methods: Bone marrow-derived mesenchymal stem cells (MSCs) were obtained from three New-Zealand male white rabbits and propagated in a primary culture for 14 days in low glucose Dulbecco's Modified Eagle's Medium (DMEM), harvested and subjected to another three passages encompassing 21 days. After that, MSCs were functionally defined by their ability to differentiate into osteoblasts. This was achieved by incubation with the DMEM containing 10-7 M dexamethasone, 10 mM βglycerophosphate and 50 µl/ml of ascorbic acid. Osteogenic differentiation was followed up at days 2, 4, 7 and 9 by staining cells with alizarin red S and vonKossa. Results: It was found that the onset of differentiation was at day 7 and continued at day 9. On the other hand, another patch of MSCs were induced into insulin-producing cells by two step incubation. The first with high glucose serum-free DMEM containing 0.5 mmol/L β-mercaptoethanol for three days and the second follows by incubation with the same medium containing 10 mmol/L nicotinamideinstead of β-mercaptoethanolfor 18 days. Trans-differentiation was followed up at days 4, 9, 14 and 21. It was found that the cells have trans-differentiated into insulin-producing cells starting from day 14 and continued in the subsequent days as judged by their affinity to stain with diphenylthiocarbazone (dithizone or DTZ) at days 14 and 21. Conclusion: The results would provide some insights of using rabbit's bone marrow as a source of MSCs with their differentiation potentials. This might help for the development of a future stem cell therapy for diabetes as well as several other human diseases.
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