Non-enzymatic antioxidant defences
Changes in the concentration of uric acid, its oxidized form (allantoin) and GSH are shown in Fig.1B–D.
The three studied organs showed a significant increase of uric acid concentration during estivation, but a significant decrease after arousal was only observed in the kidney (Fig.1B). Uric acid levels in the midgut gland of active controls were higher than those in other organs, which may be correlated with the occurrence of urate tissue in the midgut gland. However, a strikingly large increase in uric acid concentration occurred in the kidney during estivation, so that the kidney levels became not statistically different from the midgut gland (Fig.1B). This was surprising, since the kidney is devoid of specialized urate tissues.
The large increase in renal uric acid concentrations during estivation was further studied by histological examination of the kidney. The epithelium lining the renal chamber in active animals (Fig.2A) shows small basophilic or brown urinary concretions within large apical vesicles of renal epithelial cells. Estivating animals showed a marked increase in epithelial cell size, while the number, size and density of the urinary concretions, and of the concretion-containing vesicles, also increased. These urinary concretions were mostly basophilic structures within the apical vesicles, often with dark brown cores (Fig.2B). In some estivating animals, cryptal enlargement and disorganization occurred and large and dark brown concretions were contained within vesicles of many cells (Fig.2C). Also, hemocyte islets were interspersed between the epithelial crypts (Cueto, 2011); they appeared reduced in size and occasionally disorganized during estivation.
A large and statistically significant increase of allantoin concentration (indicative of uric acid oxidation) also occurred in kidney and foot after 24h of arousal (compared with active control and estivating animals; Fig.1C). Also, the allantoin concentration was higher in the kidney than in the midgut gland and foot, in both active control animals and those 24h after arousal. In addition, midgut gland concentrations were higher than those in the foot during the activity–estivation cycle (Fig.1C).
GSH concentrations in the kidney drop significantly in estivating versus active control animals, and they rose significantly at 20min after arousal (Fig.1D). Furthermore, GSH levels in kidney and midgut gland decreased significantly between active control and aroused 24h snails. No significant differences between experimental groups occurred in the foot (Fig.1D).
The midgut gland showed GSH levels higher than those of the foot, at all times during the activity–estivation cycle. Likewise, levels of GSH in the midgut gland were higher than those found in the kidney during estivation (Fig.1D).
เอนไซม์เป็นสารต้านอนุมูลอิสระป้องกันการเปลี่ยนแปลงในความเข้มข้นของกรดยูริก ตัวออกซิไดซ์ฟอร์ม (allantoin) และ GSH แสดงใน Fig.1B–Dศึกษาอวัยวะสามแสดงให้เห็นว่าเพิ่มความเข้มข้นกรดยูริกระหว่าง estivation แต่การลดลงอย่างมีนัยสำคัญหลังจากอารมณ์พบว่า เฉพาะในไต (Fig.1B) ระดับกรดยูริกในต่อม midgut ของตัวควบคุมที่ใช้งานได้สูงกว่าผู้ที่อยู่ในอวัยวะอื่น ๆ ซึ่งอาจมีความสัมพันธ์กับการเกิดขึ้นของเนื้อเยื่อของเกลือยูเรตในต่อม midgut อย่างไรก็ตาม เพิ่มขนาดใหญ่อันโดดเด่นในความเข้มข้นของกรดยูริกเกิดขึ้นในไตระหว่าง estivation ที่ระดับไตก็ไม่แตกต่างทางสถิติจาก midgut ต่อม (Fig.1B) นี้เป็นน่าแปลกใจ ไตเป็นไร้เนื้อเยื่อเฉพาะเกลือยูเรตThe large increase in renal uric acid concentrations during estivation was further studied by histological examination of the kidney. The epithelium lining the renal chamber in active animals (Fig.2A) shows small basophilic or brown urinary concretions within large apical vesicles of renal epithelial cells. Estivating animals showed a marked increase in epithelial cell size, while the number, size and density of the urinary concretions, and of the concretion-containing vesicles, also increased. These urinary concretions were mostly basophilic structures within the apical vesicles, often with dark brown cores (Fig.2B). In some estivating animals, cryptal enlargement and disorganization occurred and large and dark brown concretions were contained within vesicles of many cells (Fig.2C). Also, hemocyte islets were interspersed between the epithelial crypts (Cueto, 2011); they appeared reduced in size and occasionally disorganized during estivation.A large and statistically significant increase of allantoin concentration (indicative of uric acid oxidation) also occurred in kidney and foot after 24h of arousal (compared with active control and estivating animals; Fig.1C). Also, the allantoin concentration was higher in the kidney than in the midgut gland and foot, in both active control animals and those 24h after arousal. In addition, midgut gland concentrations were higher than those in the foot during the activity–estivation cycle (Fig.1C).ความเข้มข้นของ GSH ในไตลดลงอย่างมากใน estivating เมื่อเทียบกับการใช้งานควบคุมสัตว์ และพวกเขาเพิ่มขึ้นอย่างมีนัยสำคัญที่ 20min หลังจากอารมณ์ (Fig.1D) นอกจากนี้ GSH ระดับในต่อมไตและ midgut ลดลงอย่างมีนัยสำคัญระหว่างการใช้งานควบคุมและกระตุ้น 24h หอยทาก ไม่มีความแตกต่างอย่างมีนัยสำคัญระหว่างกลุ่มทดลองที่เกิดขึ้นในการเดินเท้า (Fig.1D)ต่อม midgut พบรอบสูงกว่าเท้า ตลอดเวลาระหว่างกิจกรรม – estivation ระดับ GSH ทำนองเดียวกัน ระดับของ GSH ในต่อม midgut ได้สูงกว่าที่พบในไตระหว่าง estivation (Fig.1D)
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