母鼠牙周炎与早产及仔鼠出生体质量关系的实验研究

An Experimental Study on Periodontal Diseases as a Possible Risk Factor for Preterm Low-birth Weight

目的探讨母鼠牙周炎与早产及仔鼠出生体质量之间的关系。方法将45只雌性SD大鼠随机分为3组(n=15):单侧或双侧结扎下颌第一磨牙并向龈沟内注射牙龈卟啉单胞菌(Pg)建立轻度牙周炎模型组(A组)和重度牙周炎模型组(B组);另外一组为空白组(C组),不结扎,不注射Pg。8周后,3组雌性大鼠均与雄性大鼠交配受孕,观察3组大鼠的怀孕周期、新生仔鼠的数量、体质量和窝质量,同时检测产后大鼠外周血中的肿瘤坏死因子-α(TNF-α)、前列腺素E2(PGE2)和基质金属蛋白酶-9(MMP-9)的水平。结果 (1)3组大鼠孕周期和新生仔鼠的体质量差别无统计学意义(P>0.05);A、B组各出现1、2只死胎,B组出现1例早产,新生仔鼠的数量和窝质量均低于C组(P<0.05)。(2)A、B组大鼠外周血中的TNF-α和PGE2水平均高于C组(P<0.05),且B组的TNF-α水平高于A组(P<0.05),但3组大鼠的MMP-9水平无明显差别(P>0.05)。(3)3组大鼠新生仔鼠数量和窝质量与大鼠外周血中TNF-α及PGE2水平呈负相关(P<0.05),但与MMP-9无明显相关(P=0.0518)。结论孕鼠分娩仔鼠数量的减少和窝质量的减轻(即疑似低出生体质量)可能与牙周感染有关,且牙周感染越严重新生仔鼠的数量越少,窝质量也越轻。

Objective To evaluate the effect of periodontal condition on preterm low-birth weight.Methods Forty-five female SD rats were randomly divided into 3 groups.The periodontitis model was established by ligating one of the mandibular first molars（Group A） or both（Group B） with orthodontic steel-wires（0.25 in diamater） and injected with Porphyromonas gingivalis into the gingival grooves;in Group C,the teeth were unligated.After 8 weeks,all the rats were sacrificed.The cycle of pregnancy and body weight of the newborn rats were recorded.The specimens were routinely processed.Histological examination and serum levels of TNF-α,PGE2 and MMP-9 were assessed.Results There was no significant difference in weight of the newborn rats and gestation time.There was one preterm birth in both Group A and B,and one dead fetus in group B.The number and total weight of the newborn rats of both Group A and B were lower than those of Group C（P0.05）.Compared with Group C,Group A and B showed higher serum levels of TNF-α and PGE2;TNF-α level of Group B was higher than that of Group A（P0.05）;serum levels of MMP-9 were not significantly different among three groups（P0.05）.The number and total weight of the newborn rats were negatively correlated with the serum levels of TNF-α and PGE2（P0.05）,but not with the serum levels of MMP-9（P=0.0518）.Conclusion The findings suggest that periodontal diseases may be a possible risk factor for preterm low-birth weight of rats.