醋酸甲羟孕酮和复方庚酸炔诺酮对 BALB/c小鼠下生殖道感染沙眼衣原体敏感性的影响

Effects of medroxyprogesterone acetate and compound norethisterone enanthate on the susceptibility of BABL/c mice to lower reproductive tract infection with Chlamydia trachomatis

目的：比较醋酸甲羟孕酮和复方庚酸炔诺酮对小鼠下生殖道感染沙眼衣原体敏感性的影响。方法60只雌性 BALB/c 小鼠随机分为6组，分别为空白对照组、醋酸甲羟孕酮对照组、复方庚酸炔诺酮对照组、无性激素处理感染组、醋酸甲羟孕酮感染组、复方庚酸炔诺酮感染组。其中，空白对照组、醋酸甲羟孕酮对照组和复方庚酸炔诺酮对照组小鼠在接受相应的激素单次处理后第5天通过阴道接种 MyCoy 细胞悬液；无性激素处理感染组、醋酸甲羟孕酮处理感染组和复方庚酸炔诺酮处理感染组小鼠在接受相应的激素单次处理后第5天通过阴道感染接种含1×10^7 E 型沙眼衣原体包涵体形成单位（ifu）的悬液。接种后第4、7、14天，采集小鼠的阴道冲洗液进行细胞培养，并在每个时间点每组随机选取3只小鼠处死，取阴道、子宫标本固定，HE 染色镜检。采用χ2检验比较不同组别的感染率。结果接种后对照组均无沙眼衣原体生长，无性激素处理感染组和复方庚酸炔诺酮感染组在接种沙眼衣原体后第4天培养阳性率均为1/10，第7天和14天均无沙眼衣原体生长；醋酸甲羟孕酮感染组在接种后第4天培养阳性率为7/10，第7天为2/7，第14天无沙眼衣原体生长。Fisher 精确概率计算显示，醋酸甲羟孕酮感染组接种后，第4天感染率高于无性激素处理组和复方庚酸炔诺酮感染组（P =0.03）；而第7天醋酸甲羟孕酮感染组感染率与其他两个组差异无统计学意义（P =0.23）。醋酸甲羟孕酮处理的两组在接种后第4天、第7天和第14天阴道内黏液增多，阴道复层鳞状上皮变薄，上皮细胞黏液化，管腔有分泌物，黏膜下层少量炎症细胞浸润，接种沙眼衣原体后第4天阴道发生病理变化，即管腔出现大量炎性分泌物，组织轻度水肿，黏膜下层少量炎症细胞浸润。复方庚酸炔诺酮处理的两组在各时间点阴道表现均正常，而子宫在接种后7 d，出现组织轻度水肿，腺腔扩张，分泌物潴留，散在炎细胞浸润。结论小鼠经醋酸甲羟孕酮处理后动情周期固定在动情间期，阴道上皮黏液化，可能有助于增加小鼠沙眼衣原体在阴道内感染的敏感性。经复方庚酸炔诺酮处理后小鼠动情期没有明显改变，子宫有改变，而这不能改变沙眼衣原体在阴道内感染的敏感性。

Objective To compare the effects of medroxyprogesterone acetate （MPA） and compound norethisterone enanthate （CNE） on the susceptibility of BABL/c mice to lower reproductive tract infection with chlamydia trachomatis （Ct）. Methods A total of 60 BALB/c mice were randomly and equally divided into 6 groups：MPA-pretreated control group and CNE-pretreated control group inoculated with MyCoy cell suspensions in the vagina on the 5th day after single treatment with MPA and CNE respectively, blank control group receiving no treatment, MPA-pretreated infected group and CNE-pretreated infected group inoculated with 1 × 10^7 inclusion-forming units（IFU）of Ct serovar E in the vagina on the 5th day after single treatment with MPA and CNE respectively, control infected group inoculated with the same quantity of IFU of Ct serovar E in the vagina but receiving no pretreatment. On day 4, 7 and 14 after inoculation, vaginal irrigation fluid was obtained from all the mice for cell culture of Ct. Three mice were randomly selected from each of these groups at the above three time points and sacrificed, and vaginal and uterine tissue specimens were obtained for hematoxylin-eosin（HE）staining and microscopic examination. Chi-square test and Fisher＇s exact test were conducted to compare infection rate among different groups. Results No growth of Ct was observed in the three control groups at the above time points. The culture-positive rate of Ct was 1/10 on day 4 but 0 on day 7 and 14 in both the CNE-pretreated infected group and control infected group, 7/10 on day 4, 2/7 on day 7 but 0 on day 14 in the MPA-pretreated infected group. Fisher＇s exact test revealed that the culture-positive rate of Ct was significantly higher in the MPA-pretreated infected group than in the control infected group and CNE-pretreated infected group on day 4 （both P =0.03）, but similar among the three infected groups on day 7 （P = 0.23）. Both the MPA-pretreated control group and infected group showed an increase in endovaginal mucus, thinning of vaginal stratified squamous epithelium, mucification of vaginal epithelium, presence of secretions in vaginal lumen and submucosal infiltration of a few inflammatory cells on day 4, 7 and 14, as well as appearance of pathological changes （including the presence of large quantities of purulent secretions in lumen, mild tissue edema and submucosal infiltration of a few inflammatory cells） in the vagina on day 4. Vaginal tissues were normal in both the CNE-pretreated infected group and control group at the above three time points, but mild tissue edema, lumen expansion, secretion retention and infiltration of scattered inflammatory cells were observed in the uterus on day 4 after inoculation. Conclusions MPA can arrest the estrous cycle of mice at diestrus with the mucification of vaginal epithelium, which may increase the susceptibility to Ct vaginal infection in mice. In contrast, CNE has no obvious effect on the estrous cycle and susceptibility to Ct vaginal infection despite of the appearance of pathological changes in the uterus.