Facultad de Odontología, Universidad Nacional de Córdoba, Argentina; Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina.
Arch Oral Biol. 2013 Nov;58(11):1643-51. doi: 10.1016/j.archoralbio.2013.08.003. Epub 2013 Aug 17.
Tooth eruption is a multifactorial process in which bone tissue plays a prevailing role. In this study we evaluated the bone overlying the developing tooth germ and the degree of tooth eruption of the first mandibular molar in pups born to mothers subjected to constant light during pregnancy.
Pregnant rats were divided into two groups: mothers chronically exposed to a 12:12 light/light cycle (LL) from day 10 to 20 of pregnancy and controls (C) maintained on a 12:12 h light/dark cycle. Pups from each group were euthanized at the age 3 or 15 days. Buccolingually oriented sections of mandibles were stained with haematoxylin-eosin or for histochemical detection of tartrate resistant acid phosphatase (TRAP). The histomorphometric parameters evaluated were bone volume, number of osteoclasts, TRAP+ bone surface, number of TRAP+ and TRAP- osteoclasts per mm(2) and degree of tooth eruption (mm).
It was found an increase in bone volume (LL: 58.14±4.24 vs. C: 32.31±2.16; p<0.01) and a decrease in the number of osteoclasts (LL: 3.5±0.65 vs. C: 8.03±1.31; p<0.01) and TRAP+ cells (LL: 0.84±0.53 vs. C: 8.59±1.26; p<0.01) in 3-day-old pups born to LL-exposed mothers. These observations are consistent with the decrease in the degree of tooth eruption observed in 15-day-old experimental pups (LL: -0.605±0.05 vs. C: -0.342±0.02; p<0.0001).
Our results suggest that chronic constant light applied as a pre-natal stressor impairs the resorptive capacity of osteoclasts involved in the formation of the eruption pathway and consequently the degree of tooth eruption.
牙齿萌出是一个多因素的过程，其中骨骼组织起着主要作用。在这项研究中，我们评估了覆盖发育中牙胚的骨组织和第一下颌磨牙萌出的程度，这些磨牙来自于孕期持续光照暴露的母鼠所生的幼崽。
将怀孕的大鼠分为两组：从妊娠第 10 天到第 20 天，母鼠持续暴露于 12:12 光照/光照周期（LL）（LL 组），而对照组（C）则保持 12:12 小时光照/黑暗周期。每组的幼崽在 3 或 15 天时被安乐死。将下颌骨的颊舌向切片用苏木精-伊红或抗酒石酸酸性磷酸酶（TRAP）的组织化学染色进行染色。评估的组织形态计量学参数包括骨体积、破骨细胞数量、TRAP+骨表面、每平方毫米的 TRAP+和 TRAP-破骨细胞数量以及牙齿萌出程度（mm）。
发现在来自 LL 暴露母鼠的 3 日龄幼崽中，骨体积增加（LL：58.14±4.24 vs. C：32.31±2.16；p<0.01），破骨细胞数量减少（LL：3.5±0.65 vs. C：8.03±1.31；p<0.01）和 TRAP+细胞减少（LL：0.84±0.53 vs. C：8.59±1.26；p<0.01）。这些观察结果与在来自 LL 暴露母鼠的 15 日龄实验幼崽中观察到的牙齿萌出程度下降一致（LL：-0.605±0.05 vs. C：-0.342±0.02；p<0.0001）。
我们的结果表明，作为产前应激源的慢性持续光照会损害参与萌出途径形成的破骨细胞的吸收能力，从而影响牙齿萌出的程度。
