Preparation And Toxicity Study Of Calcium Nanoparticles

Vaccine adjuvants for human have been the focus of attention in recently years. Aluminium compounds are the most extensively used adjuvants in licensed vaccines for humans. Although they effectively enhance humoral immune responses, there are several disadvantages associated with their use. The disadvantages of alum-based adjuvants include the severity of local tissue irritation, the longer duration of the inflammatory reaction at the injection site, minimal induction of cell-mediated immunity, and a propensity to elicit undesirable immunoglobulin E (IgE) responses.Nanoparticle technology has been one of the focuses in drug carrier systems. Nanoparticles carriers could be used to increase the availability of drug for oral uptake, targeted release drugs, controlled or sustained release drugs, across the physical barriers and so on. Nanoparticles carriers were used for enhanced therapeutic efficacy or reduced toxicity. There are several studies reported nanoparticles used as vaccine adjuvant for tumors or AIDS in foreign countries. Nanoparticles, used as vaccine adjuvant, could enhance the protective immunity of vaccine, prolong the protective immunity and alter the route of vaccination.Previous studies have demonstrated that anti-idiotypic antibody NP30 may represent a promising vaccine candidate for schistosomiasis japonica. Calcium(Ca) nanoparticles could enhance significantly the protective immunity of NP30 against infection of Schistosomajaponicum, CA-NP30 conjugate enhanced both humoral and cellular immune-4 -responses in mice. Ca nanoparticle could act as a vaccine adjuvant of anti-idiotypic antibody NP30 against schistosomiasis. In this study, Ca nanoparitcles were prepared and the acute and long-term toxicity of Ca nanoparitcles was also investigated to evaluate the safety of Ca nanoparitcles for humans. Objectives1. To prepare and identify Ca nanoparitcles.2. To observe the acute toxicity and death of the mice to which calcium nanoparticles were given in maximal dose and obtain the lethal dose 50(LD50) or the maximal tolerance dose (MTD).3. To investigate the toxic effects of the rats to which calcium nanoparticles were given twice per week, in order to offer reference of the safe dose for humans.Methods1. The Ca nanoparitcles were prepared by precipitation method at different temperatures, buffers or mixing orders.2. The structure, particle size, morphology and components of resulting nanoiparticles were characterized by transmission electron microscope (TEM), particle meter and X-ray photoelectron spectrometer (XPS).3. The acute toxicity test: Both sexes of ICR mice (weight 18-22g) were randomly divided into 2 groups. For one group, Ca nanoparitcles were administered by oral gavage to the mice at a total dose of 2.76g/kg (2 individual doses of 1.38g/kg), separated by 6-hour intervals. For the other, Ca nanoparitcles were administered by intraperitoneal injection in a single total dose of 1.15g/kg.4. The long-term toxicity test: Both sexes of sixty SD rats (weight70-90g) were randomly divided into 3 groups. Ca nanoparitcles were administered, by intraperitoneal injection in 100 mg/kg, 5mg/kg twice a week for three monthes, exposure to 2 separate groups (each containing 10 male and 10 female animals). A third group served as an control group administered by intraperitoneal injection with 0.5% sodium carboxymethylcellulose (CMC-Na). During the period of observation, the following indexes were concerned: exercise, signs per day, body weight food-eating quantity per week. After 3 months 10 rats( both sexes) of each group were sacrificed, hemogrotm, blodbiochemistry, organs facter were examined, heart liver, spleen, lungs, kidneys, brain, adrenal glands thymus glands stomach lymph nodes prostate, testicles, uterus and ovaries were extracted for pathologic examination, heart, liver, spleen lungs kidneys and brain for electron microscope examination and apoptosis study. Results1. It was indicated that granular nanop...