Objective Application of Case-based teaching method (CTM) in the class of Experimental Animal Quality Control aims to break the traditional teacher-centered and textbookcentered teaching model,to invoke students' interest and creativity by integrating practice and theory,and to cultivate their capacity in identifying,analyzing and solving problems.Methods According to different requirements of teaching contents,students were organized to discuss practical cases about quality control of experimental animals through problem-centered learning style.Results Students' capacity was enhanced in terms of problem solving with acquired knowledge,and the ability to pursue new knowledge,the intriguing and vivid cases stimulated students' interest,activated classroom atmosphere,and helped improve teaching efficiency.Conclusion Experimental animal quality control is a complicated system; Case-based teaching method leads to higher efficacy of the course of Experimental Animal Quality Control.

In recent years,many kinds of animal models of human diseases with different genetic background were developed.Some were established in China,others were imported from abroad.Precious were these animal models,their biological features could be lost for various reasons,for instance,reverse from mutation,lost of modified or constructed gene,etc.This study provided some suggestions for scientific management of the animal models to in terms of quarantine inspection,specific feeding method and methods to maintain gene stability,so as to preserve their biological features.

Objective:To evaluate the effects of exposure of fine particle matter (PM 2.5) and ozone (O 3) in Beijing as the main pollutants on olfaction of SD rats. Methods:In October 16, 2018, twenty 8-week-old SD rats were randomly divided into two groups, 10 rats in the exposure group and 10 rats in the control group. They were fed in air pollutant exposure system and clean experimental environment respectively, and the concentrations of PM 2.5 and O 3 in each system were measured. The degree of olfaction damage of SD rats at different feeding time was assessed by using the buried food test (BFT). The difference of BFT time between the two groups was analyzed by performing the repeated measures analysis of variance. Results:The results showed that the concentrations of PM 2.5 and O 3 in the exposure group were (22.65±11.47) μg/m 3 and (12.36±5.87) μg/m 3, respectively, while those in the control group were both 0 μg/m 3. The repeated measures analysis of variance showed that the time of BFT in the exposure group was longer than that in the control group ( F=6.49, P=0.031). With the increase of feeding time, the time of BFT was prolonged ( F=61.69, P<0.001). Conclusion:Exposure to PM 2.5 and O 3in the atmosphere might lead to olfaction damage in rats.

Objective:To evaluate the effects of exposure of fine particle matter (PM 2.5) and ozone (O 3) in Beijing as the main pollutants on olfaction of SD rats. Methods:In October 16, 2018, twenty 8-week-old SD rats were randomly divided into two groups, 10 rats in the exposure group and 10 rats in the control group. They were fed in air pollutant exposure system and clean experimental environment respectively, and the concentrations of PM 2.5 and O 3 in each system were measured. The degree of olfaction damage of SD rats at different feeding time was assessed by using the buried food test (BFT). The difference of BFT time between the two groups was analyzed by performing the repeated measures analysis of variance. Results:The results showed that the concentrations of PM 2.5 and O 3 in the exposure group were (22.65±11.47) μg/m 3 and (12.36±5.87) μg/m 3, respectively, while those in the control group were both 0 μg/m 3. The repeated measures analysis of variance showed that the time of BFT in the exposure group was longer than that in the control group ( F=6.49, P=0.031). With the increase of feeding time, the time of BFT was prolonged ( F=61.69, P<0.001). Conclusion:Exposure to PM 2.5 and O 3in the atmosphere might lead to olfaction damage in rats.

Objective:To evaluate the effects of fine particle matter(PM2.5)and ozone(O3)com-bined exposure on adenosine triphosphate(ATP)amount and ATPase activities in nasal mucosa of Spra-gue Dawley(SD)rats.Methods:Twenty male SD rats were divided into control group(n=10)and exposure group(n=10)by random number table method.The rats were fed in the conventional clean environment and the air pollutant exposure system established by our team,respectively,and exposed for 208 d.During the exposure period,the concentrations of PM2 5 and O3 in the exposure system were moni-tored,and a comprehensive assessment of PM2 5 and O3 in the exposure system was conducted by combi-ning self-measurement and site data.On the 208 d of exposure,the core,liver,spleen,kidney,testis and other major organs and nasal mucosal tissues of the rats were harvested.Each organ was weighed and the organ coefficient calculated.The total amount of ATP was measured by bioluminescence,and the ac-tivities of Na+-K+-ATPase and Ca2+-ATPase were detected by spectrophotometry.The t test of two inde-pendent samples was used to compare the differences among the indicator groups.Results:From the 3rd week to the end of exposure duration,the body weight of the rats in the exposure group was higher than that in the control group(P＜0.05),and there was no significant difference in organ coefficients be-tween the two groups.The average daily PM2 5 concentration in the exposure group was(30.68±19.23)μg/m3,and the maximum 8 h ozone concentration(O3-8 h)was(82.45±35.81)μg/m3.The chemi-luminescence value(792.4±274.1)IU/L of ATP in nasal mucosa of the rats in the exposure group was lower than that in the control group(1 126.8±218.1)IU/L.The Na+-K+-ATPase activity(1.53±0.85)U/mg in nasal mucosa of the rats in the exposure group was lower than that in the control group(4.31±1.60)U/mg(P＜0.05).The protein content of nasal mucosa in the control group and the exposure group were(302.14±52.51)mg/L and(234.58±53.49)mg/L,respectively,and the ac-tivity of Ca2+-ATPase was(0.81±0.27)U/mg and(0.99±0.73)U/mg,respectively.There was no significant difference between the groups.Conclusion:The ability of power capacity decreased in the rat nasal mucossa under the sub-chronic low-concentration exposure of PM2 5 and O3.