ABSTRACT
BACKGROUND: The transgenic plant anti-caries vaccine has gradually demonstrated its unique advantages due to its simple production process, low price, good immunogenicity, safety and effectiveness, and has become a research focus in recent years. OBJECTIVE: To immunize the Sprague-Dawley rats with transgenic tomatoes carrying chimeric protein of PAcA/CTB by gavage and to observe the immunogenicity and immunoreactivity in the rats. METHODS: Male Sprague-Dawley rats were randomly divided into a positive control group, an experimental group and a negative control group, in which the rats were given deactivated Streptococcus mutans, transgenic tomatoes carrying PAcA/CTB, and normal tomatoes by gavage, respectively, at 1 week after establishment of dental caries models in animals. The intragastric administration was done once a week for 4 continuous weeks. Blood and saliva samples of rats were collected before immunization and 1, 2, 3, and 4 weeks after immunization to detect the levels of IgG and sIgA antibodies against Streptococcus mutans PAcA by ELISA. The upper and lower molars of the rats at the age of 57 days were scored for dental caries. The study protocol was approved by the Laboratory Animal Ethics Committee of Zunyi Medical University. RESULTS AND CONCLUSION: Compared with the negative control group, positive control and experimental groups had a significant increase in the levels of anti-PAcA sIgA in saliva at 1, 2, 3, and 4 weeks after immunization (P < 0.01). Compared with the negative control group, the positive control group showed a significant increased level of anti-PAcA IgG in serum at 1-4 weeks after immunization (P < 0.05), while the experimental group had a significantly increased level of anti-PAcA IgG in serum at 2-4 weeks after immunization (P < 0.01). Tooth damage was minimized, only a few of caries reached the superficial dentin layer, and the number of caries was the least in the positive control group, followed by the experimental group and the negative control group in turn. To conclude, the transgenic tomatoes expressing PAcA/CTB has certain immunogenicity and immunoreactivity which can effectively immunize the rats by gavage and reduce the incidence of dental caries.
ABSTRACT
Objective To increase the mechanic characteristic of bovine jugular veins conduit (BJVC) by combined knitted stent outside made of nylon fiber. Methods Get rid of the cells of BJVC by enzymolysis, then combined a fabric stent with a acellular bovine jugular vein conduit that cross-linked dealed by photooxidation method to improve the mechanic function of BJVC. To compare the mechanical function and histology change of BJVC combined with fiber stent outside with that of BJVC only without stent. BJVC combined with fiber stent outside was divided into experiment group and the latter into control group. Two roller pumps on cardiopulmonary bypass unit were designed to simulate the pulmonary circulation. One produce the stream, and the other assist to bring a certain pressure by regulating a degree of tightness. The pressure of forward stream was used in messuring extension rate and leakage volume of two BJVC groups, and the pressure of backward stream was used in messuring the regurgitation volume. Results Set the formula to calculate the rate of variation of BJVC diameter under a certain pressure or not. The experiment group extension rate was zero under pressure of 10-20 mm Hg, about ( 7.7 ± 2.3 ) % under pressure of 40 mm Hg, until 60 mm Hg to ( 11.4 ± 3.1 ) %. While the control group reached about ( 14.8 ± 4.7 ) % at 20mm Hg already. There was no regurgitation volume of the experiment group under pressure of 30 mm Hg vs. the control group' s reached 34ml/min at 30 mm Hg while the two groups were same under pressure that lower than 20 mm Hg. When the pressure higher, the difference between the two groups more notable. There was no leakage of the BJVCs with fabric stent till pressure from 40 mmHg to 60mmHg, vs. the control group 1,5, 13 ml/min at pressure 30, 40, 60 mm Hg. Except the regurgitation and leakage volumes under pressure at 10 -20 mm Hg, as the two numerical values were both zero that can not be caculated by the statistic software, the differences of the two groups above had statistics significance. In vivo, 9 dogs received bovine jugular vein conduit transplant procedure to observe the mechanic fnction and tissue reaction. Five adopted B.JVC with stent and four just BJVC only. Six month later after the transplant procedure, there was no significant difference between the two groups but more inflaming cells than the former group, especially at the location round the nylon fibers. Through the observation in HE stain, that was considered as foreign body reaction. Conclusion Fabric stent can improve the mechanical function of BJVC and relatively easy to get.