妊娠晚期腹腔注射酸性磷酸缓冲液对两个近交系小鼠繁育生理影响的对比分析

目的对比分析妊娠晚期腹腔注射缓冲液对近交系SPF级C57BL/6J（B6）和BALB/c（B/c）小鼠繁育生理的影响。方法 B6和B/c小鼠随机、全同胞兄妹2∶1/1∶1（♀/♂）过夜同居交配,观察交配方式、阴栓与受孕率的关系;受孕鼠在妊娠的第17.5天（妊娠0d=交配后当天）接受腹腔注射酸性磷酸缓冲液,观察注射对母鼠及胚胎的作用及子鼠从离乳到8周的早期生长发育情况。结果 B6较B/c雌鼠的受孕率高（29.4%vs.21.1%[2∶1],33.2%vs.29.7%[1∶1]）;交配后10 d～14 d,根据雌鼠增大的腹部、结合体重来判断受孕较观察阴栓更为准确;比较而言,妊娠晚期腹腔注射对B6母鼠及胚胎的影响较大,表现在离乳子鼠数量减少（4.7±3.1 vs.6.1±2.1,P=0.231）,离乳时两性别的子鼠体重（g,雌性：11.7±1.1 vs.12.7±1.5;雄性：12.8±1.3 vs.13.6±1.5）显著降低（P均〈0.05）及两品系子鼠早期生长发育的方式显著不同（P=0.000）。结论近交系小鼠繁殖生理存在品系差异;两品系受孕鼠对妊娠晚期腹腔注射的耐受不同,并可能影响实验动物产后的哺乳过程及子鼠的早期生长发育。

Comparative Analysis of the Impact of Intraperitoneal Injection of Acidic Phosphate Buffer Solution at the Late Stage of Gestation on the Reproductive Physiology in Two Inbred Mouse Strains

Objective To comparatively analyze the impact of intraperitoneal injection of acidic phosphate buffer solution at a late stage of gestation on the reproductive physiology in two inbred strains of C57BL/6J（B6） and BALB/c（B/c） mice.Methods One or two sisters were randomly mated with one brother in the same strain overnight,starting at the age of 10 weeks.The correlation of mating mode（1∶1 or 2∶1） and vaginal plug with pregnancy rate was observed.The pregnant dams were intraperitoneally injected with acidic phosphate buffer solution at 17.5th day of their gestation（day 0=day post mating）.The observation was carried out to detect the impact of the injection of acidic buffer on pregnant dams and their fetuses,and also the growth of the offspring from weaning to 8 weeks.Results The pregnancy rate was higher in B6 than in B/c females regardless of mating mode（29.4% vs.21.1% ,33.2% vs.29.7% ）.The better way to accurately determine pregnancy was to examine the expanded belly combined with increased body weight from day 10 to 14 post-mating.Compared with the dams of B/c strain,the impact of the peritoneal injection on those of B6 strain was stronger.It manifested a reduction in number of weaned offspring（4.7±3.1 vs.6.1±2.1）,a significant decrease（P0.05 in both genders） of the offspring＇s body weight at the time of weaning in both genders（g,female：11.7±1.1 vs.12.7±1.5;male： 12.8±1.3 vs.13.6±1.5）,and a significantly different growth pattern of the offsprings（P=0.000）.Conclusions There is a strain-dependent difference in some aspects of reproductive physiology in inbred mice.The tolerance to the intraperitoneal injection of acidic phosphate buffer solution at a late stage of gestation varied in the two strains.The procedure may produce some effect on dams＇ breeding after baby-delivery,which may continue to influence the early developmental growth of the offspring.