Sheldon I M, Noakes D E, Rycroft A N, Dobson H
Department of Veterinary Clinical Science, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK.
Anim Reprod Sci. 2004 Mar;81(1-2):13-23. doi: 10.1016/j.anireprosci.2003.08.010.
After parturition fewer first dominant follicles are selected in the ovary ipsilateral to the previously gravid uterine horn in cattle. However, the presence of a large oestradiol-secreting follicle in the ipsilateral ovary is a predictor of fertility, possibly due to a localised effect of oestradiol which increases the rate of elimination of the ubiquitous uterine bacterial contamination that occurs after calving. The present study tested the hypothesis that oestradiol reduces uterine bacterial contamination when administered into the uterine lumen around the expected time for selection of the first postpartum dominant follicle. Animals were infused with saline (n=15) or 10mg oestradiol benzoate (n=15) into the previously gravid uterine horn on Days 7 and 10 postpartum. Peripheral coccygeal blood samples were collected daily and oestradiol concentrations measured by radioimmunoassay (RIA). Uterine lumen swabs were collected 7, 14 and 21 days postpartum for aerobic and anaerobic culture, bacteria were identified and growth scored semi-quantitatively. Plasma oestradiol concentrations were higher for treated animals between Days 7 and 14 (1.4+/-0.1 versus 2.0+/-0.2 pg/ml, P<0.05). Control animals had a similar bacterial growth score on Days 7 and 14, with a lower value on Day 21 (5.7+/-1.0 and 6.1+/-0.7 versus 0.3+/-0.1, P<0.05). However, treated animals had a surprising higher bacterial load on Day 14, than on Days 7 or 21 (7.1+/-0.9 versus 4.0+/-0.6 or 3.6+/-0.6, P<0.05). The increased score was attributable to more pathogens associated with endometritis on Day 14 than Day 7 (5.1+/-1.0 versus 2.5+/-0.5, P<0.05), in particular Prevotella melaninogenicus (1.5+/-0.5 versus 0.7+/-0.2, P<0.05) and Fusobacterium necrophorum (1.5+/-0.4 versus 0.3+/-0.2, P<0.05). In conclusion, administration of oestradiol into the uterine lumen surprisingly increased uterine pathogenic anaerobic bacterial contamination. Thus, it is unlikely that increased fertility associated with a first dominant follicle in the ipsilateral ovary is a consequence of the elimination of bacterial contamination by ovarian oestradiol.
分娩后，牛的先前妊娠子宫角同侧卵巢中被选择的初始优势卵泡数量减少。然而，同侧卵巢中存在一个分泌大量雌二醇的卵泡是生育能力的一个预测指标，这可能是由于雌二醇的局部作用，它提高了产后普遍存在的子宫细菌污染的清除率。本研究检验了这样一个假设：在首次产后优势卵泡选择的预期时间前后，将雌二醇注入子宫腔时，它会减少子宫细菌污染。在产后第7天和第10天，给动物的先前妊娠子宫角注入生理盐水（n = 15）或10mg苯甲酸雌二醇（n = 15）。每天采集外周尾静脉血样，通过放射免疫分析（RIA）测定雌二醇浓度。在产后第7、14和21天采集子宫腔拭子进行需氧和厌氧培养，鉴定细菌并进行半定量生长评分。在第7天至第14天期间，治疗组动物的血浆雌二醇浓度较高（1.4±0.1对2.0±0.2 pg/ml，P<0.05）。对照组动物在第7天和第14天的细菌生长评分相似，在第21天较低（5.7±1.0和6.1±0.7对0.3±0.1，P<0.05）。然而，治疗组动物在第14天的细菌载量出人意料地高于第7天或第21天（7.1±0.9对4.0±0.6或3.6±0.6，P<0.05）。评分增加归因于第14天与子宫内膜炎相关的病原体比第7天更多（5.1±1.0对2.5±0.5，P<0.05），特别是产黑色素普雷沃菌（1.5±0.5对0.7±0.2，P<0.05）和坏死梭杆菌（1.5±0.4对0.3±0.2，P<0.05）。总之，将雌二醇注入子宫腔出人意料地增加了子宫致病性厌氧菌污染。因此，同侧卵巢中首个优势卵泡相关的生育能力增加不太可能是卵巢雌二醇清除细菌污染的结果。
