Study On The Effect Of High Dose Vitamin C Combined With Chloroquine Or Artemisinin On Plasmodium

Malaria is a kind of parasite disease transmitted by female Anopheles mosquitoes,which seriously threatens the lives of people in developing countries,such as Africa,especially pregnant women and children.Plasmodium falciparum is the most epidemic species and causes the most severe malaria symptoms.However,the complete elimination of malaria has not been achieved because of the continuous emergence of anti-malarial drug resistant Plasmodium falciparum strains.Therefore,it is urgent for us to seek new anti-malaria drugs and new treatment strategy while blocking malaria transmission.It is reported that high-dose vitamin C inhibits the growth of tumor cells by disturbing the redox balance of tumor cells,reducing the ATP levels and finally leading to apoptosis.Like tumor cells,the blood-stage Plasmodium relies mainly on glycolysis for energy,so we speculate that high-dose vitamin C may also inhibit the growth of blood-stage parasites.In previous study,as the adjvant malaria therapy,the dose of vitamin C was below 180mg/kg,and had no effect on the parasitemia.We have shown that intraperitoneal injection of high-dose vitamin C(4g/kg)every day in infected mice could inhibit the parasite growth.The oxidized form of vitamin C(DHA)can enter the erythrocyte and parasite through the glucose transporter(GLUTs)on the plasma membrane of erythrocyte and the hexose transporter(HT)on the plasma membrane of the parasite,which disturbing the redox balance,and eventually leading to erythrocyte eryptosis and parasites apoptosis.Based on the above research basis,this study intends to further clarify the effect of high-dose vitamin C combined with antimalarial drugs in the treatment of malaria,especially for the drug-resistant P.falciparum.This study is mainly divided into two parts.In the first part,we used the drug-sensitive P.falciparum strain(Pf3D7),chloroquine-resistant strain(PfDd2)and artemisin-resistant strain(Pf803).These three strains were treated with different doses of vitamin C for 3 hours every day,and the parasitemia were detected.The results showed that the high-dose vitamin C was in a physiologically safe range and could inhibit the growth of these three strains significantly.Therefore,high-dose vitamin C also have an inhibiting effect on drug-resistant P.falciparum.Moreover,we applied high-dose vitamin C in combination with chloroquine or artemisinin to treat with two drug resistant strains.The results suggested that chloroquine or artemisinin does not affect the inhibitory effect of vitamin C on drug resistant P.falciparum.In the second part,we first constructed a mouse model of malaria using mice infected with P.berghei,and divided the infected mice into the control group,the single drug group and the drug combination group.Each group of mice was given different drug combinations: vitamin C,chloroquine,artemisinin,vitamin C plus chloroquine and vitamin C plus artemisinin,then the therapeutic effects were observed by monitoring parasitemia every day.The results displayed that the inhibition of P.berghei growth by the drug combination treatment was more obvious than that of the single drug group.To evaluate the therapeutic effect and the improvement of physiological function of the infected mice,we tested the biochemical indicators of liver function,liver and spleen weights,serum inflammatory factors levels,expression ER stress markers and apoptosis related proteins in liver and spleen.The results indicated that compared with the single drug group,the combination drug can significantly improve the liver and spleen function of the mice with malaria,inhibit the inflammation and ER stress of the liver and spleen cells,and inhibit the apoptosis of liver cells.Based on the above results,high-dose vitamin C can inhibit blood-stage chloroquine-resistant and artemisinin-resistant P.falciparum effectively in vitro,and it can play an anti-malaria role when combined with other anti-malarial drugs in vitro.When high-dose vitamin C combined with chloroquine or artemisinin is applied in infected mice in vivo,it is more effective than single drug treatment in inhibiting the growth of P.berghei and alleviating organs damage without serious side effects.Our research exploits a new direction of the anti-malarial study of vitamin C,and provides a new way to the discover advanced anti-malarial drugs and anti-malarial strategies.