Effects of pretreatment with EGTA on DNA fragmentation induced by Cd.

<p>DNA fragmentation was assayed in agarose gel electrophoresis. Crabs were pretreated with or without 5 mM EGTA for 4 h, and then exposed to 58 mg•L^-1 Cd for 48 h. The letters on the lanes represent: Con = H₂O (4 h) + H₂O (48 h); Cd = H₂O (4 h) + 58 mg•L^-1 CdCl₂ (48 h); E = 5 mM EGTA (4 h) + H₂O (48 h); and, E + Cd = 5 mM EGTA (4 h) + 58 mg•L^-1 CdCl₂ (48 h).</p

Effects of acute Cd exposure on [Ca²⁺]i in gill cells of <i>S</i>. <i>henanense</i>.

<p>Cells were loaded with 5 μM Fluo-3/AM for 30 min at 37°C in the dark, then treated with 5.8 mg•L^-1 CdCl₂ for the different times, followed by the images recording under a laser confocal microscope (LSM 510 META, Leica, Bensheim, Germany).</p

Effects of EGTA pretreatment on Cd-induced morphological variation of epithelial cells in the gill.

<p>(A) (×10000) normal epithelial cell with nucleus and a large of cytoplasmic organelles. (B) (×10000) apoptotic epithelial cell induced by 58 mg•L^-1 CdCl₂ with apoptotic characteristics, such as chromatin condensation and extremely irregular nuclear membrane in nucleus. (C) (×8000) epithelial cell treated by 5 mM EGTA alone; (D) (×6000) epithelial cell treated by 5 mM EGTA for 4 h, then exposed to Cd for 48 without apoptotic characteristics.</p

Effects of pretreatment with EGTA on the activities of caspase enzymes in the gill of crabs exposed to acute Cd treatment.

<p>The mean expression in each treated group is shown as a fold increase compared to the mean expression in the control, which had been ascribed an arbitrary value of 1. Using one-way analysis of variance and on comparing with the control, significance is shown by *<i>P</i><0.05, **<i>P</i><0.01; on comparing with Cd treatment group, ^#<i>P</i><0.05, ^##<i>P</i><0.01.</p

Effects of Cd exposure on CaM content and Ca²⁺-ATPase activity in gill cells.

<p>Results are presented as mean ± SE; n = 3. *<i>P</i><0.05, **<i>P</i><0.01 difference vs. control group.</p

Cd concentration analysis in water of freshwater crab (<i>S. henanense</i>) exposed. to Cd.

<p>Data are expressed as mean ± SD. Significance is shown by</p>*<p><i>P</i><0.05, on comparing with respective nominal exposure concentration.</p

Effects of Cd on subcellular structure of <i>S. henanense</i> gills.

<p>A–B: control. (A) normal epithelial cell with nucleus and a large number of cytoplasmic organelles; (B) normal hemocyte in the gill cavity. C–E: exposure to Group C for 48 h. (C) cytoplasm of epithelial cell with the vacuolar enlargement (black triangle) and organelles reduction; (D) nucleus of epithelial cell with chromatin condensation and extremely irregular nuclear membrane; (E) hemocytes in the gill cavity with apoptotic characteristic. F–H: exposure to Group C for 96 h. (F) cytoplasm of degenerative and necrotic epithelial cells with scare organelles and broken membrane (asterisks); (G) nucleus of necrotic epithelial cells with nuclear membrane collapses (asterisks); (H) hemocytes in the gill cavity with inflammatory response. A: 6000×; B: 8000×; C: 8000×; D: 10000×; E: 10000×; F: 8000×; G: 8000×; H: 5000×. N: nucleus; LG: large granules; SG: small granules; GC: gill cavity.</p

The effects of Cd on H₂O₂ content and lipid peroxidation in the gills of <i>S. henanense</i>.

<p>(A) H₂O₂ content; (B) MDA content. The mean expression in each treatment group is shown as a fold increase compared to the mean expression in the control, which had been ascribed an arbitrary value of 1. The values are the means ± S.D. (n = 3). Asterisks indicate a significant difference to the control (*<i>P</i><0.05).</p

The effects of Cd on antioxidant enzyme activities of SOD (A), CAT (B) and GPx (C) in the gills of <i>S. henanense</i>.

<p>The values are means ± S.D. (n = 3). *Different from respective control (<i>P</i><0.05).</p

TUNEL test of Cd-induced apoptosis in gills of <i>S. </i>henanense.

<p>Stained gill section 200×. (A) control; (B) Group A; (C) Group B; (D) Group C. The apoptotic cellular nucleus was brown (circle), non-apoptotic cellular nucleus was blue.</p