犬子宮積膿之荷爾蒙、臨床病理學、子宮菌相與血漿中基質金屬蛋白酵素2與9的變化

Abstract

子宮積膿症是性荷爾蒙所誘發的一種母犬子宮常見疾病，而以黃體助孕素所扮演的角色最為重要，細菌感染的來源為發情期時子宮頸開張，處於陰道的常在菌伺機上行進入子宮內造成感染。此疾病的發生多伴隨有不同程度的腎功能異常，且常出現多渴多尿，而造成多尿的確切原因仍不明，部分犬隻於疾病後期甚至併發腎功能衰竭。基質金屬蛋白酵素（metrix metalloproteinase, MMP）為一種可分解細胞外基質成份的酵素，在正常組織重建或許多疾病發生炎症反應進行時，分泌量及活性皆上升。本研究為了解荷爾蒙對該疾病的影響與此疾病對腎功能影響的嚴重性，故以化學冷光免疫分析法（chemiluminescence immunoassay）測定患有子宮積膿犬隻及正常母犬之血漿中動情素、黃體助孕素濃度，並檢測血中尿素氮與肌酸酐濃度評估腎臟功能，再利用放射免疫分析法（radioimmunoassay）測定血漿中血管加壓素（vasopressin, VP）濃度，以了解是否與引起多尿症狀有關。在細菌的分離鑑定上抽取子宮內容物，依細菌型態與其生化反應進行細菌的分離鑑定，並使用Bauer-Kirby所改良的方法，自31個分離菌株進行抗生素敏感性試驗。另以6% SDS-PAGE含有0.2% gelatine進行電泳分析血漿中基質金屬蛋白酵素2與9的濃度變化，以了解此疾病之蛋白酵素的表現。結果患病族群之性荷爾蒙濃度與對照組間並無顯著差異，血清學檢查上患病犬隻有50%（25/50）出現氮血症（血中尿素氮>20 mg/dL），而有22%（11/50）的犬隻出現腎功能異常（肌酸酐>1.5 mg/dL）。在VP濃度變化上，患病犬隻並無分泌不足的現象，而併發腎功能異常的犬隻其濃度更顯著高於對照組（p=0.02）。而致病細菌方面以革蘭氏陰性菌占大多數（81%, 46/57），其中以E. coli為主（41%, 24/57）。抗生素敏感性試驗顯示抗藥性普遍偏高，以sulfamethoxazole的抵抗性最高（100%），gentamicin的抵抗性最低（29.0%）。而血漿及子宮組織中MMP-2及MMP-9濃度變化上，患有子宮積膿犬隻濃度顯著高於對照組犬隻。由本研究結果可知，子宮積膿疾病發生時腎功能的維持是相當重要的；而患有子宮積膿且併發腎功能異常犬隻可能由於腎臟抗利尿功能不足而引起腎因性多尿。在疾病治療時抗生素的選擇上須注意，應選用有效的抗生素，並避免濫用而導致抗藥性菌株產生。

Pyometra is one of the common reproductive system diseases associated with the estrus status in bitches. Among sex hormones, progesterone plays an important role in initiating the pathogenesis of cystic endometrial hyperplasia. The most likely source of the bacteria that establish a uterine infection is the resident bacteria of the vaginal vault. These bacteria have the potential of ascending through the relatively dilated cervix, into the uterus, during proestrous and estrus. Dogs with pyometra frequently have clinical signs of renal dysfunction, in which polyuria and polydipsia as prominent clinical signs. However, the actually mechanism of polyuria is still unknown. With further progression, renal failure in some bitches can subsequently develop in the later stage of pyometra. Metrix metalloproteinases (MMPs) are secreted by cells and are able to digest proteins of the extracellular matrix. These enzymes have been involved in many normal remodeling processes as well as in some disease. In order to realize the effect of hormones in pyometra, chemiluminescence immunoassay and radioimmunoassay were used to determine reproductive hormones (estrogen and progesterone) and vasopressin (VP) concentration in plasma, respectively. The seriousness of subsequent renal function disorder was studied by determining blood urea nitrogen (BUN) and creatinine value in pyometra dogs. The causative bacteria was isolated from uterine fluid and identified according to bacterial morphology and biochemical reaction. The identified bacteria proceed to test the antibiotics susceptibility. MMP-2 and MMP-9 expression in plasma were analyzed by 6% SDS-PAGE containing 0.2% gelatine. In results, the concentration of reproductive hormones in plasma was no significantly difference from control group. As the respect of renal function, there were 50% (25/50) of pyometra dogs with azotemia (BUN> 20 mg/dL), and 22% (11/50) of pyometra dogs had renal function disorder (creatinine> 1.5 mg/dL). VP secretory ability in pyometra dogs was not reduced, but the group of pyometra subsequent renal dysfunction had significantly higher VP concentration compared with control group (p=0.02). In identification of causative bacteria, gram-negative species is the major causative agent in this study (81%, 46/57), among which Escherichia coli was the predominant bacteria (41%, 24/57). In antibiotic susceptibility test, sulfamethoxazole had the highest resistance (100%), gentamicin was the lowest (29%). In MMPs expression in plasma, MMP-2 and MMP-9 were all expressed significantly higher in pyometra than in control dogs. According to this study, when pyometra was found, the most important thing was maintain renal function. Secondly, because of insufficient antidiuretic function, dogs with pyometra subsequent renal failure may have nephrogenic diabetes insipidus. In the end, when veterinary choose antibiotics in the therapy of dogs with pyometra needed further consideration before using to prevent the more bacteria have high antibiotic resistance.