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Aim To establish and compare asthma models among different strains of obese mice. Methods Different strains of SPF female mice, namely Kunming ( KM ) , C57BL/6J and BALB/c mice, were randomly divided into four groups ( control group, asthma group, obesity group and obese asthma group). The mice were fed a high-fat diet or a normal diet for 12 weeks, following which they were sensitized and challenged with ovalbu-min ( OVA) or phosphate-buffered saline ( PBS) . Body weight, fat weight, liver weight, Lee′s index, OVA-specific IgE concen-tration in bronchoalveolar lavage fluid ( BALF) , serum total cho-lesterol ( TC) and triglyceride ( TG) levels, and lung and adi-pose morphologies were evaluated. The specific airway resistance ( sRaw) was measured using double-chamber plethysmography. Results The mice on a high-fat diet showed a more rapid in-crease in body weight compared with those on a normal diet. Af-ter 12 weeks of feeding, body, fat, and liver weights and Lee′s index were higher for the obese mice than for the lean mice. The adipocyte cross-sectional area was significantly greater in the obese BALB/c and KM mice than in their lean counterparts;the C57BL/6J groups showed no significant differences. The BALB/c mice demonstrated more significant symptoms of acute asthma, local inflammation and airway hyper-responsiveness ( AHR ) . Conclusion Compared with C57BL/6J and KM mice, BALB/c mice fed a high-fat diet and sensitized and challenged with OVA provide the most suitable model for evaluating the relationship between obesity and asthma.
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Objective To explore an optimal method of producing STZ-induced type 1 diabetic KM mice model by investigating the molded rate of single high dose and multiple low dose of STZ injection.Methods Sixty KM mice were randomly divided into 4 groups(n=15), two control groups and two model groups.In the two control groups, one was blank control and the other was negative control.Mice in the blank control group treated with no injection, but mice in the negative control group were treated with injection of citric acid salt buffer.For the two model groups, one was single high-dose group, 150 mg/kg STZ was injected only once.The other was multiple low-dose group, 50 mg/kg STZ was injected for 5 consecutive days.After the last injection, daily food and water intake were tested, blood glucose level and body weight were examined once a week for 4 consecutive weeks. Results Mice in the two model groups showed typical features of diabetes.The blood glucose levels in the two model groups were significantly higher than in the two control groups ( P <0.05 ) .For the two model groups, the molded rate of 150 mg/kg and 50 mg/kg group were 60% and 53.33%respectively at 1st week, but at the 4th week, they were 60% and 80% respectively.The mortality of these two groups at the 4th week was 33.33% and 20% respectively.Moreover, the blood glucose level in multiple low-dose group increased stably from the 2nd week to the 4th week.Conclusion The multiple low-dose STZ injection (50 mg/kg for 5 consecutive days) is an optimal method for producing KM mice model of type 1 diabetes mellitus.
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Objective To establish a rapid and accurate method, and to determine the density of mice and rats sperm with enzyme-labeled instrument.Methods ①The optimal wavelengths and the regression equation set up: After six Kunming mice and six Sprague-Dawley rats were sacrificed, the left epididymis was separated and fully cut up in phosphate buffer saline.With water bath, the sperm were fully dissociated.Using the enzyme-labeled instrument to detect the wavelength absorbance respectively under different wavelength and fitting absorbance curve.The best wavelength will be the most close to 1 of the correlation coefficient ( R2 ) and the standard deviation of minimum.After ten Kunming mice and ten Sprague-Dawley rats were sacrificed,the sperm suspension of different concentration gradient were got.The regression equation of the sperm density and absorbance was established by using enzyme-labeled instrument and haemocytometer.②The test of sperm absorbance stability: Mice and rats,six respectively,were used to make the sperm suspension.Samples were put in room temperature (25℃) or 37℃water bath continued,and after water bath about 0,20,30,40,50, 60 min,the change of absorbance was recorded.③The regression equation verification:The mice were administrated orally with 20% ethanol solution for 30 days to make oligospermia.In order to verify the new method, two different method were used to get the sample sperm.Results The optimal absorbancy-sperm density curve could be established at 380 nm.The means of KM mice sperm count ( x1 ) and absorbance ( y1 ) are showed to be the linear function,and the linear regression equation is y1 =2 ×10 -9 x1 +0.0648, R2 =0.9743.The means of SD rat sperm count ( x2 ) and absorbance (y2) are showed to be the linear function,and the linear regression equation is y2 =5 ×10 -9x2 +0.0621,R2 =0.9940.SD rat sperm suspension liquid after 60 min in water bath, absorbance value at 0 min significantly decreased(P<0.05), but at room temperature after 40 min significantly increased ( P<0.05); KM mice sperm suspension in the water bath and under the condition of normal temperature after 50 min, compared with the 0 min, absorbance value increased significantly(P<0.05).Compared with control group, sperm density of ethanol oligozoospermia group by enzyme standard detector and standard curve calculation were significantly decreased ( P <0.05 );compared with absorbancy-sperm density equation, determination of ethanol oligozoospermia group of sperm density by cell counting plate method had not significant difference.The results suggested absorbancy-sperm density equation could effectively detect the reduction of the mice sperm in oligospermia.Conclusion Using enzyme-labeled instrument to set up the curve of absorbancy-sperm density equation can estimate the sperm density of mice and rats rapidly and exactly.
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Objective To analyze and evaluate the population genetic quality of outbred KM mice from National Rodent Seed Center ( Shanghai ) .Methods A total of 30 outbred KM mice were randomly chosen.The genetic characteristics of the population were determined by PCR and STR scanning using 30 selected microsatellite loci. Popgen1.32 software was used to process the data.Results Thirty microsatellite loci shared 123 alleles in the KM mouse population.The average effective allele number and the average heterozygosity were 2.3989 and 0.5342, respectively.The average polymorphism information content ( PIC ) was 0.4735.Conclusions The outbred KM mouse population of Shanghai Seed Center has genetic stability and genetic diversity, and is satisfied with the genetic characteristics of closed colony laboratory animal.