邹振兴等
摘要[目的] 探究奶水牛子宫脱垂的病因。[方法] 选取53头奶水牛进行产前血浆钙、磷、丙二醛(MDA)和总抗(TAC)水平检测,根据分娩后是否发生子宫脱垂分为子宫脱垂组(M)和健康对照组(UM),并分析血浆中钙、磷及氧化/抗氧化水平与奶水牛子宫脱垂发生的关系。[结果] M组奶水牛产前1周和分娩当天的血浆钙、磷含量和氧化/抗氧化水平显著低于UM组。M组奶水牛TAC水平从产前3周到分娩当天均显著低于UM组,而MDA水平显著高于UM组。[结論] 奶水牛产后子宫脱垂的发生与产前体内钙、磷水平不足和总抗氧化能力下降、过氧化产物积聚有关。
关键词奶水牛;子宫脱垂;钙;磷;抗氧化
中图分类号S823.8+3文献标识码A文章编号0517-6611(2014)06-01702-02
Abstract[Objective] The research aimed to study the metroptosis etology of dairy buffalo. [Method] 53 dairy buffaloes were selected to detect the serum calcium, phosphorus, malondialdehyde (MDA) and the total antioxidant capacity (TAC) levels. Dairy buffaloes were divided into metroptosis group (M) and healthy control group (UM) according to the metroptosis situations of buffalo. The correlation between the content of calcium and phosphorus, oxidation/antioxidation level in plasma and the occurrence of metroptosis of buffalo was analyzed. [Result] The contents of calcium, phosphorus and oxidation/antioxidation level of dairy buffalo at the prenatal week and the delivering day in M group were significantly lower than that in UM group. TAC level of dairy buffalo in M group from the first three weeks to the delivering day was significantly lower than that in UM group. MDA level in M group was significantly higher than that in UM group. [Conclusion] The occurrence of postpartum metroptosis in buffalo was related with insufficient levels of calcium and phosphorus in prepartum buffalo, declined total antioxidant capacity and the accumulation of peroxide product.
Key wordsDairy buffalo; Uterine prolapse; Calcium; Phosphorus; Antioxidant
子宫脱垂(Metroptosis)在奶水牛中是一种较为常见的产科疾病,其临床症状为子宫角、子宫体和子宫颈甚至部分阴道翻转脱出于阴门之外,称为子宫脱垂。Samad等调查表明巴基斯坦奶水牛养殖业中生殖器脱垂占产科疾病的42.9%,其中生殖器脱垂疾病中子宫脱垂、产前阴道脱出和产后阴道脱出分别占11%、67.3%和21.7%[1]。在印度的奶水牛养殖业中阴道脱出和子宫脱垂在奶水牛分娩时同时发生的概率为13.4%[2]。在我国规模化高产奶水牛养殖中,奶水牛子宫脱垂的发病率一般为5%~10%,在广西个别牛场发病率高达13.74%,尤其是在炎热的夏季发病率甚至高达30%以上,且其发病率有逐年上升的趋势[3-4],已成为影响我国部分奶水牛养殖业发展的突出问题。
奶水牛子宫脱垂的发病原因至今尚未完全确定,不少报道认为该疾病的病因复杂且归因于多个方面,国外学者认为它主要包括营养因素、激素因素[5]、季节因素[6]、管理因素[7]、遗传因素[8]和矿物元素以及微量元素等[9]方面,而国内对其病因学研究相对较少。笔者对奶水牛血浆中钙、磷、氧化与抗氧化指标进行产前动态监测,以期为探究它们与奶水牛发生子宫脱垂的关系提供科学依据。
1材料与方法
1.1实验动物
随机选取广西某规模化奶水牛场1~6胎、体重相近、体况良好的健康怀孕后期奶水牛53头,其中尼里拉菲23头、摩拉21头以及杂交牛9头。根据产后是否发生子宫脱垂,1.2血样采集
对所有试验奶水牛从产前6周开始采集血样,每周采集1次,直至分娩当天,共7个时间点,即产前6周、产前5周、产前4周、产前3周、产前2周、产前1周和产犊当天,清晨空腹进行颈静脉采血,产犊当天在奶水牛分娩后8 h内采集血样,将血样置于肝素钠抗凝的离心管中,现场迅速离心分离出血浆,置于低温冰盒内及时送至实验室检测。
3讨论
关于奶水牛子宫脱垂发生的病因研究报道非常有限。笔者通过临床与实验室检测分析初步确定血浆钙、磷含量、氧化/抗氧化水平与奶水牛子宫脱垂的发生有一定关系,为今后深入研究和临床预防提供了科学依据。
该试验表明子宫脱垂组奶水牛产前和分娩当天血浆钙、磷含量显著降低,与M.S.Akhtar[10]等和 Ahmed [11]等报道的生殖器官脱出奶水牛血浆钙、磷水平降低的结果相一致,但国外报道中未对被检奶水牛进行产前连续采血。笔者首次对子宫脱垂奶水牛进行了钙和磷水平的连续监测,发现分娩当天的血钙含量[(2.08±0.08) mmol/L]和血磷的含量[(1.30±0.15)mmol/L]与Pandit R.K.[12]等报道的印度产后子宫脱垂奶水牛血钙的含量[(1.81±0.05)mmol/L]和血磷的含量[(1.22±0.03)mmol/L]相比,该试验中血钙含量相对略高,这可能与地域因素有关。血钙对于维持神经肌肉的兴奋性、细胞膜的通透性、肌肉的收缩以及神经冲动的传导具有重要作用,血钙的降低将导致阴道和子宫支持肌肉的紧张性降低,致使子宫脱垂的发生[13]。Jacono和Robertson[14]报道血浆钙、磷含量与体内雌激素含量呈显著的负相关关系,产前奶水牛体内雌激素含量的不断升高将导致骨盆支持结构的松弛,同时也加重了血浆中钙、磷的水平的降低,从而导致子宫脱垂的发生。
关于奶水牛子宫脱垂与机体抗氧化能力的关系的研究国内尚未见报道。该试验结果表明与UM组相比,M组奶水牛产前机体抗氧化水平显著降低,而氧化产物显著升高。在发病奶水牛中,氧化/抗氧化水平与疾病严重程度有关,子宫脱垂最严重的1头牛产前1周和分娩当天血浆中TAC值在试验牛中最低、MDA值在试验牛中最高。该研究中氧化/抗氧化水平检测结果与Kas H[15]等研究报道的女性因氧化应激和抗氧化水平降低导致生殖器官脱出的结果相一致,产前机体抗氧化水平的降低将导致氧化应激的产生,体内自由基含量增高,对机体的脂肪、蛋白质和DNA造成破坏,引起分娩时各种疾病的发生。Eun Jae Kim[16]等通过对骨盆器官脱垂女性的子宫骶骨韧带进行氧化应激的生物标记,采用免疫组化对线粒体的凋亡进行观察,结果表明氧化应激和线粒体的凋亡将导致骨盆器官脱垂的发生。
从发病情况来看,试验奶水牛的子宫脱垂发病率为13.2%,各品种间发病率相似,且试验组牛都在分娩后6 h内发生子宫脱垂,发病時间很快,需要及时进行处理。
该研究表明子宫脱垂组奶水牛产前血浆中钙、磷和TAC含量显著低于对照组,而MDA含量显著高于对照组,说明奶水牛产前血浆中钙、磷和TAC水平的降低以及MDA含量的升高与子宫脱垂的发生显著相关,为临床上奶水牛子宫脱垂的监控和预防提供了理论基础和科学依据。
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