Interleukin-33 exerts pleiotropic immunoregulatory effects in response to Plasmodium berghei ANKA(PbA)infection in mice

Objective:To determine the involvement and the modulatory effects of IL-33 during Plasmodium berghei ANKA(PbA)infection.Methods:PbA infection in male ICR mice was utilized as a model of malaria.Systemically circulating IL-33 levels were determined in blood plasma by enzyme-linked immunosorbent assay(ELISA).After 24 hours post-inoculation of PbA,recombinant IL-33 and ST2,and antibodies against IL-33 and IgG treatments were administered daily for 3 days.Tissue expression and localization of IL-33 were assessed in organs generally affected by malaria via immunohistochemistry.Moreover,histopathological examination was performed to assess the effects of the treatments.Results:The levels of systemic IL-33 were elevated at the critical phase of PbA infection.Likewise,immunohistochemical analysis revealed a significant upregulation of IL-33 expression at the critical phase in the brain,lungs,and spleen of PbA-infected mice as compared to healthy controls.Treatment with IL-33 protected against experimental cerebral malaria development and reduced pathological features in the brain and lungs of the PbA-infected mice.Conclusions:A potential critical role and involvement of IL-33 in PbA infection may hint at the resolution of immunopathological sequelae associated with malaria.

Antimalarial potential of kolaviron,a biflavonoid from Garcinia kola seeds,against Plasmodium berghei infection in Swiss albino mice

Objective:To investigate the antimalarial potential of kolaviron(KV),a biflavonoid fraction from Garcinia kola seeds,against Plasmodium berghei(P.berghei)infection in Swiss albino mice.Methods:The study consists of seven groups of ten mice each.Groups I,II and III were normal mice that received com oil.KV1 and chloroquine(CQ),respectively.Groups IV,V,ⅥandⅦwere infected mice that received corn oil.CQ,KYI and KV2.respectively.CQ.KY1 and KV2were given at 10-,100-and 200-mg/kg daily,respectively for three consecutive days.Results:Administration of KV1 and KV2 significantly(P<0.05)suppressed P.berghei-infection in the mice by 85%and 90%.respectively,while CQ produced 87%suppression relative to untreated infected group after the fifth day of treatment.Also,KV2 significantly(P<0.05)increased the mean survival time of the infected mice by 175%.The biflavonoid prevented a drastic reduction in HCV from day4 of treatment,indicating its efficacy in ameliorating anaemia.Significant(P<0.05)oxidative stress assessed by the elevation of serum and hepatic malondialdehydewere observed in unlrealed P.berghei-infected mice.Specifically,senum and hepatic malondialdehyde levels increased by93%and 78%,resjiectively in the unlrealed infecled mice.Furlhennore,antioxidant indices,viz;superoxide dismutase.catalase,glutathione-s-transferasc.glualhione peroxidase and reduced gluathione decreased significantly(P<0.05)in the tissues of untreated P.berghei-infected mice.KV significantly(P<0.05)ameliorated the P.berghei-induced decrease in antioxidant status of the infected mice.Conclusions:This study shows that kolaviron,especially at 200 mg/kg,has high antimalarial activities in P.berghei-infected mice,in addition to its known antioxidant properties.

Nauclea latifolia aqueous leaf extract eliminates hepatic and cerebral Plasmodium berghei parasite in experimental mice

Objective: To assess the effects of hot water leaf extract of Nauclea latifolia(N. latifolia) on antioxidant status, lipid peroxidation values and parasite levels in hepatic and brain tissue of experimental mice(BALB/c) infected with Plasmodium berghei(P. berghei) malaria.Methods: Forty nine mice were divided into seven groups(n = 7) and used for the study. Group A(control) were given 0.2 m L/kg phosphate buffer saline; Group B mice were infected with P. berghei and treated with phosphate buffer saline. Groups C and D mice were also infected but treated with 200 and 300 mg/kg body weight of leaf extract respectively. Groups E and F mice were not infected, but received 200 and 300 mg/kg of leaf extract respectively. Group G mice were infected and treated with chloroquine(5 mg/kg). Liver and brain tissues of mice were prepared for both biochemical assay and microscopic examination. Results: Results showed that P. berghei malaria infection induced oxidative stress in both liver and brain tissues as evidenced by the significant(P < 0.05) decrease in antioxidants: superoxide dismutase, reduced glutathione and catalase. These reductions perhaps caused compromise in membrane integrity as indicated by the significant increase in lipid peroxidation product malondialdhyde. Malaria parasites were also identified in these tissues. However, N. latifolia treatment eliminated the parasites in tissues and protected them from oxidative damage even better than chloroquine treatment did, whose anti-malarial potency also cleared tissue parasites. The measurement of protection by N. latifolia against damage was strengthened by the insignificant micro structural alterations.Conclusions: The bioactive phytochemical(s) in N. latifolia should be structured and the mechanism(s) of its antimalarial tendency should be further investigated.

Immunogenicity and immunizing protection effect of GAMA gene DNA vaccine on Plasmodium berghei

Objective: To explore the effect of immunogenicity and immunizing protection of GAMA gene DNA vaccine, which was related with merozoite, ookinete and sporozoite invasion. Methods:Gene fragments were obtained using PCR technique and eukaryotic expression vector(containing immunostimulatory sequence) was built. BALB/c mice were divided into PBS control group, empty vector control group and study group and were immunized at week 0, 3 and 6 respectively. Blood was collected 2 weeks after each immunization and serum was separated to detect the Ig G, Ig G1 and Ig G2 a levels. Spleen of mice was obtained for preparation of splenic mononuclear cell and the cytokine IL-4 and IFN-αlevels were detected. Indirect immunofluorescence and western blot were employed to verify the specificity of antiserum. Sporozoite and merozoite invasion were used respectively to detect the immune protective effect 2 weeks after the third immunization. Ookinete conversion rate in vitro and oocyst numbers of mosquito stomach were observed to evaluate the transmission-blocking levels. Results: In GAMA DNA vaccine group: antiserum could be combined with recombinant protein specifically and green fluorescence signals of merozoite, ookinete and sporozoite were observable, while specific fragments and fluorescence signals were not observable in empty vector group. Compared with control group, specific Ig G in DNA vaccine immunity group significantly increased(P<0.01), and Ig G1 and Ig G2 a all increased(P<0.01). IL-4, IFN-αcontent in study group significantly increased, compared with control group(P<0.01). GAMA DNA vaccine immunity could not obviously block the erythrocyte-stage infection(caused by sporozoite invasion); compared with control group, liver worm load was slightly reduced(P<0.05), and antiserum ookinete numbers(cultured in vitro) had no significant difference with oocyst numbers of mosquito stomach in DNA vaccine group. Conclusions:GAMA has good antigenicity, which could stimulate the body to produce specific immune responses; while DNA vaccine immunity could not play a good protective effect, the effect of which is only limited to the slight reduction of liver worm load, and has no obvious erythrocytestage protective effect and transmission-blocking effect. Therefore, trying other immunization strategies for further research on the value of GAMA(as multi-stage antigen vaccine and multistage combined vaccine components of the life-cycle of plasmodium) is necessary.

Gut Microbiota Reconstruction Following Host Infection with Bloodstage Plasmodium berghei ANKA Strain in a Murine Model

Malaria remains a global health problem.The relationship between Plasmodium spp.and the gut microbiota as well as the impact of Plasmodium spp.on the gut microbiota in vertebrate hosts is unclear.The aim of the current study was to evaluate the effect of blood-stage Plasmodium parasites on the gut microbiota of mice.The gut microbiota was analyzed by 16S rRNA sequencing and bioinformatic analyses at three stages.The gut microbiota changed during the three phases:the healthy stage,the infection stage,and the cure stage(on the 9th day after malarial elimination).Moreover,the gut microbiota of these infected animals did not recover after malaria infection.There were 254 operational taxonomic units(OTUs)across all three stages,and there were unique strains or OTUs at each stage of the experiment.The percentages of community abundance of 8 OTUs changed significantly(P<0.05).The dominant OTU in both the healthy mice and the mice with malaria was OTU265,while that in the cured mice was OTU234.In addition,the changes in OTU147 were the most noteworthy.Its percentage of community abundance varied greatly,with higher values during malaria than before malaria infection and after malaria elimination.These results indicated that the external environment influenced the gut microbiota after host C57BL/6 mice were infected with blood-stage P.berghei ANKA and that the same was true during and after elimination of blood-stage P.berghei ANKA.In addition,we could not isolate OTU147 for further study.This study identified gut microbiota components that were reconstructed after infection by and elimination of blood-stage P.berghei ANKA in host C57BL/6 mice,and this process was affected by P.berghei ANKA and the external environment of the host.

Antimalarial activity of the aqueous extract of Euphorbia cordifolia Elliot in Plasmodium berghei-infected mice

Objective:To evaluate the antimalarial activity of the aqueous extract of Euphorbia(E.)cordifolia Elliot against Plasmodium(P.)berghei-infected mice.Methods:Thirty healthy Swiss mice were intraperitoneally inoculated with 200μL of P.berghei parasitized-erythrocytes and divided into five groups,and then daily treated for 5 d with single dose of 10 mL/kg of distilled water for malaria control,10 mg/kg of chloroquine for the chloroquine control and 100,200 and 400 mg/kg of the aqueous extract of E.cordifolia for the three test groups.Parasitaemia was monitored by Giemsa-staining.At the end of the treatment,animals were sacrificed,and blood was collected for haematological and biochemical analyses.Organs were collected for biochemical and histopathological analyses.Statistical significance(P<0.05)was evaluated by analysis of variance followed by the Tukey post-test using Graphpad prism 7.0.Results:E.cordifolia extract decreased the parasite load to 2.46%,with an effective dose(ED50)of 113.07 mg/kg compared to the malaria group where the parasite load increased to(46.46±10.28)%.E.cordifolia extract prevented hypoglycaemia,anaemia,leucocytosis and thrombocytopenia,attenuated the increase of transaminases activities,bilirubin and creatinine rate,and improved catalase and superoxide dismutase activities,while reducing malondialdehyde contents in the liver and kidney.E.cordifolia extract significantly prevented histological damages observed in the malaria control group.No acute toxicity sign was observed in mice with plant extract at the dose up to 5000 mg/kg.Conclusions:E.cordifolia extract at 200 and 400 mg/kg showed significant antimalarial effects.This results support its traditional use in the treatment of malaria.

Nano chloroquine delivery against Plasmodium berghei NK65 induced programmed cell death in spleen

Objective:To compare the protective effects of chitosan-trypolyphosphate(CS-TPP) nanoparticle conjugated chloroquine(CQ) with effect of CQ alone on the reversal of splenic damages and induction of apoptosis.Methods:Different researches have been carried out to explore the potential role of chitosan based drug delivery system against parasitic diseases.After successive Plasmodium berghei NK65 parasiste infection by intraperitoneal injection in Swiss mice and subsequent parasite development,the ROS generation,anti-apoptotic and pro apoptotic protein levels in spleen were measured.To analyze caspases,flow cytometry study was performed with annexin 桋-FITC and with PI staining.Results:The results revealed that ROS mediated caspase 3 and 9 activation and the induction of apoptosis occurred during the parasitic infection.However,CS-TPP conjugated CQ was relatively better in reversing the splenic damage compared with similar effects of CQ alone.Conclusions:This study indicates that Plasmodium berghei NK65 induces apoptosis in the spleen.The study further shows that CS-TPP nanoparticles conjugation with CQ have positive influence on the recovery of damaged host's system towards maintenance of normal homeostasis,and this is shown to be selective to CS-TPP conjugated CQ treated animals only.

Effects of the methanolic seeds extract of Carica Papaya on plasmodium Berghei infected mice

Objective:The leaves extract of Carica Papaya（C.Papaya）papaya has been shown to possess antimalarial activity, thus this work aims at finding out if the plants antimalarial activity is present in or extended to the seeds.Methods:The seeds of C.papaya were collected from its fruit,air dried for 5 days and ground into fine powder.80.65 g of the powder was then soaked for 48hours in 300 mL of methanol.Filtration was carried out using Whatman No.1 filter paper.The filtrate was evaporated to dryness by a three-day continuous heating on a hot plate of 30℃.The dry extract yield was scraped out of the Petri dish weighed and refrigerated until required. The percentage extract yield was calculated out from the initial powder weight.A preliminary phytochemical study was done by re-dissolving the appropriate amount of the dry extract in distilled water and appropriate test reagent added.The LD50 of the seeds of C.papaya was carried out using arithmetic method.Swiss albino Mice of both sexes and of average weight of 18-25 g were used as animals for antimalarial activity.They were housed in standard animal house,fed on Rats/Mice pellets and had non restricted excess to both feed and water throughout the 60day study period.While the non pregnant female Mice were used as test animals,the male animals were used as malaria parasite donors.Precautions were taken to ensure that all animals in the study groups were free from infection with Eperythrozoon coocoides.The female animals were then divided into three main groups（A-C） of 25 animals per group.Group A was used for malaria suppressive study（early infection -day 0-3） and was further subdivided to 5 subgroups（a-e） of 5animals per group.Group B was used for malaria curative study（established malaria infection-day 3-7） and was further subdivided to 5subgroups（a-e） of 5animals per group.Group C was used for malaria prophylactic study（repository-4days treatment prior to malaria parasite infection） and was also further subdivided into 5subgroups（a-e） of 5animals per group.At the appropriate time,50 mg/kg/day,100 mg/kg/day and 200 mg/kg/day of crude extract of C.papaya were administered orally to the different subgroups（b-d） within the three main groups.One subgroup（a） in each main group also received orally,5 mg/kg/day of chloroquine phosphate as positive control while one subgroup （e） in each main group also received orally,0.2 mL/kg/day of distilled water as negative control.Malaria parasites infected red blood cells numbering 1×10 and suspended in 0.2 mL of physiological saline was inoculated intraperitoneally,to each animal of the subgroups（a-d） in each of the three main groups at the appropriate time.Blood smears were made from animals’tail,stained with Lieshman and examined microscopically at 100×for the presence of malaria parasite.Percentage malaria parastaemia was calculated as well as average percentage malaria parasitaemia suppression.Results:Extraction yield of 25.29%was obtained while the LD50 was 620 mg/kg.The phytochemistry showed the richly presence of alkaloids,as well as glycosides,carbohydrates, resins,fats and fixed oils.The suppressive study at doses of 200,100 and 50mg/kg/day showed 53.02%,43.43%and 19.83%suppressive activity against Plasmodium berghei respectively.This activity compared to that of chloroquine,a standard antimalaria drug that gave 95.95%suppressive anti-parasitaemia. The prophylactic study at doses of 200,100 and 50 mg/kg/day showed 63.85%,61.12%and 48.08%prevention to malaria parasitaemia respectively as against 94.78%showed by chloroquine.The curative study however,at doses of 200,100 and 50 mg/kg/day failed to suppress malaria parasitaemia with a mean survival range of 6-8days as against 27.2 days showed by chloroquine.The seeds extract of C.papaya showed a significant malaria parasitaemia suppressive activity（P≤0.05）.These activities are dose dependent and comparable to those of Chloroquine phosphate.Conclusion:The results above suggest that the seeds extracts of C.papaya possess antimalarial activity like the leaf extracts.The antimalarial activity may be attributable to the richly presence of alkaloids and or the presence of its proteolytic enzyme（Papain）.The present finding justifies the inclusion of the seeds of C.papaya in the treatment of malaria by local herbalists.The seeds extracts therefore,if well purified and characterized may be used in treatment of very early plasmodiasis as well as a good prophylactic drug in human.This work at the moment is limited to animals,thus clinical trials in humans is be recommended particularly,when C.papaya seeds are non harmful/non toxic.

Effect of pre-existing Schistosoma haematobium infection on Plasmodium berghei multiplications in imprinting control region mice

Objective: To investigate the effect of pre-existing Schistosoma haematobium(S. haematobium) infection on malaria disease severity.Methods: The study involved the use of twenty-i ve imprinting control region mice, i fteen of which were initially infected with S. haematobium. Five of the remaining ten schistouninfected mice together with i ve schisto-infected mice were infected with Plasmodium berghei(P. berghei) after four weeks(acute stage) of schistosoma infection. The remaining i ve schisto-uninfected mice together with i ve schisto-infected mice were also infected with P. berghei after seven weeks(chronic stage) of schistosoma infection. The last i ve schistoinfected mice were used as control group. They were then monitored for changes in P. berghei parasitaemia on Days 3, 5, 7, 9 and 11 post-infection. Records on their survivability were also taken.Results: The co-infected mice had signii cantly higher malaria parasitaemia, compared with the mono-infected mice during acute S. haematobium infection. In contrast, the co-infected mice had signii cantly lower malaria parasitaemia during chronic S. haematobium infection and a higher survival rate.Conclusions: Co-infection of mice with P. berghei during acute S. haematobium infection resulted in rapid P. berghei development and increased malaria parasitaemia. However, the co-infection resulted in slower P. berghei development and decreased malaria parasitaemia with enhanced survivability of the mice during chronic S. haematobium infection. Therefore, pre-existing chronic S. haematobium infection may provide some protection to the host by reducing parasitaemia.

Pharmacodynamic evaluation for antiplasmodial activity of Holarrhena antidysentrica(Kutaja) and Azadirachta indica(Neemb) in Plasmodium berghei infected mice model

Objective:To investigate in-vivo anti-plasmodial activity of aqueous extracts of plants selected based on the symptomology mentioned in Ayurveda.Methods:The aqueous extracts of Holarrhena antidysentrica(H.antidysentrica)(Kutaja) and Azadirachta indica(A.indica)(Neemb) for their antiplasmodial potential in Plasmodium berghei(P.berghei) infected mice was assessed using Peters four day suppressive test.Both the extracts were administered at 2 dose levels,full dose(1 000 mg/d) and minimized dose(200 mg/d).10~6 P.berghei infected RBCs were injected on day ’0’ and treated from day ’0’ till day ’3’ post-infection,Tail blood smears were collected, giemsa stained and analyzed.The mice were observed for survival and parasitemia was assessed till 50%of mice in control survived.Results:It was observed that the percentage of parasitemia increased gradually in all the groups,with maximum in control group(Day 3-35,Day 9-46.98) and minimum in Chloroquine arm(Day 3-14.06.Day 9-19.92).The percentage of parasitemia was compared using Mann-Whitney U test depicting that all test groups exhibited reduction in parasitemia as compared to control(P-value【0.002 for all groups).These groups showed similar percentage of survival as Chloroquine.Conclusions:The present investigation demonstrated the anti-plasmodial effects of H.antidysentrica and A.indica.which are two most commonly used medicinal plants in Ayurved for treatment of fever.

Antioxidant Activities of Ethanoilc Extracts of Spilanthes uliginosa, Ocimum basilicum, Hyptis spicigera and Cymbopogon citratus against Swiss Mice Exposed to Plasmodium berghei Anka 65

Malaria infection is associated with increased generation of free radicals. This study investigated the antioxidant activity of ethanolic leaf extracts of Spilanthes uliginosa, Ocimum basilicum, Hyptis spicigera and Cymbopogon citratus. Seventy two (72) swiss mice of both sexes were used. All the mice were treated intraperitoneally with 0.2 ml parasitized blood suspension and parasitemia assessed by thin blood films stained with Geimsa stain after seventy two hours. The mice were divided into six groups namely;A, B, C, D, E, and F of twelve mice each. Groups B, C, D and E were subdivided into three (3): B1, B2, B3, C1, C2, C3, D1, D2, D3, E1, E2 and E3, four in each subgroup. The subgroups were treated with the extracts of Spilanthes uliginosa (Sw), Ocimum basilicum, Hyptis spiligera and Cymbopogon citratus each for five (5) consecutive days with 200, 400 and 800 mg/kg body weight respectively via oral intubation. Two control groups, A and F were used. The negative control (A) was treated daily with 5 ml/kg normal saline while positive control group (F) was treated with 5 mg/kg body weight of chloroquine. The results indicated a general significant (P < 0.05) decrease in the lipid peroxidation concentrations of the parasitized treated mice when compared to parasitized untreated mice on the last day. A general significant dose dependent increase (P < 0.05) was observed in superoxide dismutase (SOD), catalase and glutathione perioxidase activities as well as reduced glutathione concentrations in the treated mice except at a dosage of 200 mg/kg body weight for all the plants. The effects of the extracts were significantly higher (P < 0.05) than that of chloroquine. These results suggest that the ethanolic extracts of these plants may contribute to the protection of malaria infected mice against oxidative damage by improving antioxidant status in a dose dependent manner.

In vivo combination therapy of chloroquine and stigmasterol against Plasmodium berghei induced pathologies in mice

Objective:To investigate the effect of combination therapy of chloroquine and stigmasterol on Plasmodium berghei(thereafter referred to as P.berghei)malaria-induced organ pathologies.Methods:Thirty five mice weighing 20-30 g were placed into seven groups of five mice each and distributed as uninfected administered 100 mg/kg BW stigmasterol,uninfected administered only feed and water ad libitum,infected with P.berghei and-administered 50 mg/kg BW stigmasterol,100 mg/kg BW stigmasterol,100 mg/kg BW stigmasterol plus 5 mg/kg BW chloroquine,and 5 mg/kg BW chloroquine.The last group of mice served as P.berghei infected and not treated control.The levels of parasitemia,packed cell volume,and other biochemical parameters were measured.Results:Combination therapy of P.berghei infection with stigmasterol and chloroquine did not significantly(P>0.05)reduce parasitemia level while stigmasterol treatment alone significantly(P<0.05)reduced the parasitemia level.However,the P.berghei induced anemia was decreased significantly(P<0.05)upon treatment with a combination of chloroquine and stigmasterol as well as with stigmasterol alone.Furthermore,the combination of chloroquine and stigmasterol significantly(P<0.05)decreased the activities of serum alanine aminotransferase,aspartate aminotransferase,urea and spleen total proteins levels in P.berghei mice in comparison with the untreated group.Treatment of P.berghei infected mice with stigmasterol alone and in combination with chloroquine significantly(P<0.05)increased the level of serum creatinine while serum and spleen malondialdehyde levels were significantly(P<0.05)decreased.Levels of glutathione in spleen and kidney were insignificantly(P>0.05)altered upon treatment with both doses of stigmasterol as well as the combination therapy.Conclusions:This study concluded that the combination of stigmasterol and chloroquine could combat anemia and some organ pathologies associated with P.berghei infection.

Antiplasmodial Efficacy of Crude Cocoa Powder Extract on CD4+ T-Cell Counts of <i>Plasmodium berghei</i>Infected BALB/c Mice

Background: Drug resistance in malaria warrants the need for alternative therapy from plant food nutrients. The search for novel anti-malarial control spurred a great interest in cocoa which has been portrayed as immune booster against malaria. This study was geared towards estimation of CD4+ cells of P. berghei infected mice treated with cocoa powder extract (CPE) to provide substantive scientific evidence to authenticate the anecdotal report. Methods: Brine shrimp toxicity assay was done to determine LC50 of crude cocoa powder extract. The mice were infected with 1 × 107 of ANKA and NK65 strains of Plasmodium berghei intraperitoneally, while graded doses of the extract were administered by an intra-gastric intubation based on the body weight of mice. Blood samples were analyzed for microscopy and flow cytometry for CD4+ cell counts. Results: The onset of infection was delayed in the group treated before inoculations on day 3 and the level of P. berghei parasitemia was positively associated with induction of CD4+ cells while the negative control group that received normal saline had progressive increase of parasitemia. The mean survival time could not go beyond day14 in ANKA, though both strains responded to CPE in a similar way with chloroquine as a positive control. The CD4+ cells counted increased in both strains treated before and during inoculations and the episodes of malaria was suppressed compared with the control. Conclusion: This study has demonstrated that the antiplasmodial activity of CPE was associated with the level of CD4+ T-cells proliferation which initiated the protective immune response. This therefore calls for efforts to ensure adequate intake of cocoa powder to boost immunity against malaria.

In vivo combination therapy of chloroquine and stigmasterol against Plasmodium berghei induced pathologies in mice

Objective:To investigate the effect of combination therapy of chloroquine and stigmasterol on Plasmodium(P.)berghei malaria-induced organ pathologies.Methods:Totally 35 mice weighing 20-30g were placed into 7 groups of 5 mice each and distributed as uninfected administered 100 mg/kg BW stigmasterol,uninfected administered only feed and water ad libitum,infected with P.berghei and administered 50 mg/Kg BW stigmasterol,100 mg/kg BW stigmasterol,100 mg/kg BW stigmasterol plus 5 mg/kg BW chloroquine,and 5 mg/kg BW chloroquine.The last group of mice served as P.berghei infected and not treated control.The levels of parasitemia,packed cell volume,and other biochemical parameters were measured.Results:Combination therapy of P.berghei infection with stigmasterol and chloroquine did not significantly(P>0.05)reduce parasitemia level while stigmasterol treatment alone significantly(P<0.05)reduced the parasitemia level.However,the P.berghei induced anemia was decreased significantly(P<0.05)upon treatment with a combination of chloroquine and stigmasterol as well as with stigmasterol alone.Furthermore,the combination of chloroquine and stigmasterol significantly(P<0.05)decreased the activities of serum alanine aminotransferase,aspartate aminotransferase,urea and level of spleen total proteins in P.berghei infected mice in comparison with the untreated group.Treatment of P.berghei infected mice with stigmasterol alone and in combination with chloroquine significantly(P<0.05)increased the level of serum creatinine while serum and spleen malondialdehyde levels were significantly(P<0.05)decreased.Levels of glutathione in spleen and kidney were insignificantly(P>0.05)altered upon treatment with both doses of stigmasterol as well as the combination therapy.Conclusions:This study concluded that the combination of stigmasterol and chloroquine could combat anemia and some organ pathologies associated with P.berghei infection.

Comparative effects of parenteral antimalarials in Swiss albino mice after chronic exposure to Plasmodium berghei

Mice are considered to be a similar model to humans in the pathogenesis of malaria. This study evaluates the effect of parenteral antimalarials on the spleen and liver of Swiss albino mice after chronic exposure to Plasmodium berghei. After chronic exposure to P. berghei NK65 strain, the level of parasitemia was assessed.The mice were treated for 3 days using chloroquine(5 mg/kg), quinine(10 mg/kg),and artemether(2 mg/kg). The effect of chronic exposure and the pattern of recovery were evaluated. There was significant decrease in total body weight after chronic exposure to P. berghei(P < 0.05). An increase in total weight recovery was seen after day 15 of treatment with the antimalarials; this was more pronounced with artemether. A significant increase in liver and spleen weights due to P. berghei infection was seen. There was a recovery pattern due to decrease in liver and spleen weights following antimalarial administration, which was greatest with artemether(P < 0.05). Significant changes were more in parasitized, quinine and artemether groups(P < 0.05). There was a significant decrease in total spleen protein due to chloroquine but a decrease due to quinine and artemether(P < 0.05). No significant changes in liver and spleen albumin were observed after treatment. The highest parasite clearance was observed with artemether, followed by quinine. Five mice died after chronic exposure in all the groups prior to treatment. There was significant enlargement and discoloration of spleen and liver after chronic exposure. This study showed that artemether aided recovery of the liver and spleen better than quinine and chloroquine in albino mice after chronic exposure to P. berghei. This suggests there is potential for improvement in antimalarial therapy.

Apoptosis of erythrocytic stage parasites of Plasmodium berghei chloro-quine-resistant strain

Objective: To explore the characteristics of crisis state at erythrocytic stage of Plasmodium berghei chloroquine-resistant (RC) strain. Methods: Agarose electrophoresis, optical and transmission electron microscopes were used. Patterns of genomic DNA structures and ultra-structures of the erythrocytic parasites were observed in ICA mice (infected with the RC strain) during rising and declining of parasitemia. Results: During the declining parasitemia, the erythrocytic stage parasites of the RC strain showed round or oval appearance with intact plasma membrane and shrank nuclei with no metabolic window, mitochondria or other membranaceous structures. Their DNA electrophoretogram revealed a ladder pattern which evidently differed from the parasites of the RC strain in the rising parasitemia and the chloroquine-sensitive (N) strain.Conclusion: The crisis state of the erythrocytic stage parasites of the P. berghei chloroquine-resistant (RC)strain is characterized by apoptosis.

为从变形体 berghei 的氮的氧化物 synthase 和类似的蛋白质的结构和功能的生物信息学分析和预言

【正】Objective:To search and analyze nitric oxide synthase(NOS) and similar proteins from Plasmodium berghei(Pb).Methods:The structure and function of nitric oxide synthase and similar proteins from Plasmodium berghei were analyzed and predicted by bioinformatics. Results:P6NOS were not available,but nicotinamide adenine dinucleotide 2’-phosphate reduced tetrasodium(NADPH)-cytochrome p450 reductase(CPR) were gained.PiCPR was in the nucleus of Plasmodium berghei,while 134aa-229aa domain was localize in nucleolar organizer. The amino acids sequence of P6CPR had the closest genetic relationship with Plasmodium vivax showing a 73%homology.The tertiary structure of PbCPR displayed the forcep-shape with wings,but no wings existed in the tertiary structure of its’ host,Mus musculus(Mm).137aa-200aa, 201aa-218aa,220aa-230aa,232aa-248,269aa-323aa,478aa-501aa and 592aa-606aa domains of P6CPR showed no homology with MmCPRs’,and all domains were exposed on the surface of the protein.Conclusions:NOS can’t be found in Plasmodium berghei and other Plasmodium species.PbCPR may be a possible resistance site of antimalarial drug,and the targets of antimalarial drug and vaccine.It may be also one of the mechanisms of immune evasion.This study on Plasmodium berghei may be more suitable to Plasmodium vivax.And137aa-200aa, 201aa-218aa,220aa-230aa,232aa-248,269aa-323aa,478aa-501aa and 592aa-606aa domains of PbCPR are more ideal targets of antimalarial drug and vaccine.

Asiatic acid-pectin hydrogel matrix patch transdermal delivery system influences parasitaemia suppression and inflammation reduction in P. berghei murine malaria infected Sprague-Dawley rats

Objective: To report the influence of transdermal delivery of asiatic acid(AA) in Plasmodium berghei-infected Sprague Dawley rats on physicochemical changes, %parasitaemia and associated pathophysiology. Methods: A topical once-off AA(5, 10, and 20 mg/kg)- or chloroquine(CHQ)-pectin patch was applied on the shaven dorsal neck region of Plasmodium berghei-infected Sprague Dawley rats(90-120 g) on day 7 after infection. Eating and drinking habits, weight changes, malaria effects and %parasitaemia were compared among animal groups over 21 d. Results: AA-pectin patch application preserved food and water intake together with %weight gain. All animals developed stable parasitaemia(15%-20%) by day 7. AA doses suppressed parasitaemia significantly. AA 5 mg/kg patch was most effective. AA and CHQ displayed bimodal time-spaced peaks. CHQ patch had a longer time course to clear parasitaemia. Conclusions: AA influences bio-physicochemical changes and parasitaemia suppression in dose dependent manner. In comparison by dose administered, AA has much better efficacy than CHQ. AA may be a useful antimalarial. AA and CHQ displays bimodal peaks suggesting possible synergism if used in combination therapy.

基于16S rDNA高通量测序探讨肠道菌群对疟原虫感染小鼠的保护性作用

目的探究Plasmodium berghei ANKA(P.bANKA)感染小鼠肠道菌群特异性改变及其保护性研究。方法C57BL/6小鼠随机分为正常对照组(NC组)和P.bANKA感染组(P.b A组),动态留取粪便进行16S rDNA高通量测序。建立益生菌预处理组(Pre-probiotics+P.b A组),伊文思蓝灌注评估血脑屏障(BBB)完整性,苏木精-伊红(HE)染色,观察脑组织病理学改变。结果16S rDNA高通量测序分析,P.bANKA感染小鼠后肠道菌群以乳酸杆菌和罗伊乳酸杆菌明显下降为主要变化趋势,且呈时间依赖性。动物验证实验发现,与P.b A组相比,Pre-probiotics+P.b A组原虫血症水平较低,小鼠于感染后第14 d开始出现死亡且未发生脑疟神经系统症状,BBB完整性较好,脑组织无明显损伤。结论P.bANKA感染可明显改变宿主肠道菌群的结构和功能,其中以乳酸杆菌数量减少最为明显。外源性补充乳酸杆菌后可明显降低ECM小鼠原虫血症水平,提高生存率。其作用机制可能与保护BBB完整性,改善小鼠脑组织病理损伤密切相关。

瑞香素杀疟原虫裂殖体的作用(英文)

[目的 ]研究中药瑞香素在体外和体内的杀裂殖体作用。 [方法 ]在恶性疟原虫FCCl株常规体外培养中测试瑞香素杀裂殖体活性 ,并按“四天抑制性试验”在感染伯氏疟原虫ANKA株的小鼠中测定不同剂量瑞香素的体内抗疟活性。 [结果 ]体外试验中瑞香素在 1～ 10 μmol L剂量范围内有明显杀灭裂殖体作用 ,而体内试验中按D4减虫率与感染鼠在 30d内的平均生存天数评价 ,5 0或 10 0mg kg .d- 1 × 4d瑞香素灌胃以及 10 ,5 0或 10 0mg kg.d- 1 × 4d瑞香素腹腔注射给药在伯氏鼠疟原虫ANKA株感染鼠中的抗疟作用与 10mg kg .d- 1 × 4d氯喹 (CQ)灌胃的疗效相似。 [结论 ]瑞香素在体外和体内均有一定的杀裂殖体作用。