バベシアビゲミナに自然感染した牛の酸化ストレス、微量元素、シアル酸、コリンエステラーゼ活性の状態

Status of oxidative stress, trace elements, sialic acid and cholinesterase activity in cattle naturally infected with Babesia bigemina.

• Bijan Esmaeilnejad
• Mousa Tavassoli
• Bahram Dalir-Naghadeh
• Awat Samiei
• Sepideh Rajabi
• Vahid Mohammadi
• Ehsan Anassori
• Shahin Ehteshamfar

抄録

バベシアビゲミナ感染症（テキサス熱とも呼ばれる）は、世界的に最も流行しているウシバベシア症の主な原因菌として報告されている。本研究では、B. bigemina に自然感染した牛を対象に、抗酸化酵素活性、総抗酸化能（TAC）、生体分子の酸化状態、血清微量元素レベルなどの酸化ストレスの指標、シアル酸（SA）含量、コリンエステラーゼ活性などの炎症の指標を評価した。20頭の交雑種ホルスタイン牛（3～4歳）からなる感染群は、顕微鏡検査と入れ子状PCR法の両方で陽性と診断された。感染牛は寄生率（<20％と>20％）に応じて2つのグループに分けた。さらに、10頭の健常牛をコントロールとして加えた。感染により、寄生虫の負担に依存して重度の貧血が発生した。カタラーゼとグルコース-6-リン酸デヒドロゲナーゼの活性、TAC、亜鉛、セレン、銅、マンガンのレベルは、寄生虫の増加に伴って有意に低下した。しかし、スーパーオキシドジスムターゼの活性は、マロンジアルデヒド、タンパク質のカルボニル化、DNA損傷、鉄のレベルと同様に、寄生虫の負担に依存した方法で有意に上昇した。また、グルタチオンペルオキシダーゼ活性は、寄生率が低いほど有意に上昇したが、寄生率が高いほど対照と比較して有意な影響はなかった。さらに、総量、タンパク質および脂質結合SA量は有意に増加したが、アセチルコリンエステラーゼおよびブチルコリンエステラーゼの活性は寄生率に依存して有意に低下した。結論として、感染は貧血、酸化ストレス、炎症の誘発と顕著に関連していた。

Babesia bigemina infection (also known as Texas fever) is reported as the most prevalent and main causative agent of bovine babesiosis, worldwide. The current study was undertaken to assess indicators of oxidative stress including activities of antioxidant enzymes and total antioxidant capacity (TAC), oxidation status of biomolecules and serum levels of trace elements as well as indicators of inflammation including sialic acid (SA) contents and cholinesterase activity in cattle naturally infected with B. bigemina. An infected group comprised of 20 crossbred Holstein cattle (3-4 years old) were diagnosed to be positive by both microscopy and nested PCR assay. The infected animals were subdivided into two groups according to their parasitemia rates (<20 % and>20 %). Furthermore, 10 healthy cattle were included as the control. The infection caused severe anemia in a parasitemia-burden dependent fashion. The activities of catalase and glucose-6-phosphate dehydrogenase as well as the levels of TAC, zinc, selenium, copper and manganese were significantly decreased as the parasitemia increased, accordingly. However, the activity of superoxide dismutase as well as the levels of malondialdehyde, protein carbonylation, DNA damage and iron, were significantly elevated in a parasitemeia-burden dependent manner. Additionally, glutathione peroxidase activity was significantly elevated with the lower rate of parasitemia, but the higher rate had no significant effect as compared to control. Moreover, total, protein and lipid binding SA contents were significantly increased but the activities of acetylcholinesterase and butyrylcholinesterase were significantly reduced, parasitemia dependently. Conclusively, the infection was remarkably associated with the induction of anemia, oxidative stress and inflammation.

Copyright © 2020. Published by Elsevier Ltd.