Ectoxicology Lab, Department of Environmental Science, The University of Burdwan, Burdwan, 713104, West Bengal, India.
Ectoxicology Lab, Department of Environmental Science, The University of Burdwan, Burdwan, 713104, West Bengal, India.
Ecotoxicol Environ Saf. 2020 Apr 1;192:110268. doi: 10.1016/j.ecoenv.2020.110268. Epub 2020 Feb 6.
Present study highlighted the ultramicroscopic (SEM) alterations of the skin, eye, barbel, and fins of spawn of an air-breathing teleost (Clarias batrachus, Linn. 1758) induced by UV-B radiation (280-320 nm) at a dose (@4.07 × 10J/photon/m) under the time-frame of 5, 10 and 15 min/d in the laboratory condition for the periods of 5 and 10 days. Limnological parameters revealed no significant changes throughout the period of experimentation which were measured by PCS Testr 35 Multi-Parameter. Morphometric analysis revealed that during the extended exposure period of 10 days the spawn size and weight were reduced as analysed through Specific Growth Rate (SGR). SGR values in terms of weight for 5 and 10 days under 3 time-frames were 17.12%, 12.52%, 11.46% and 9.09%, 6.43%, 6.09% respectively, which revealed a declined trend along with the exposure days. In the skin of C. batrachus, the compact regular orientation of the stratified epithelial cells and mucous cells became distorted and the microridges and double-ridged structures showed destruction and fragmentations. The body striations and microfolds became shrinked and swollen and finally degenerated to form a mass. The distribution of mucous cells throughout the epidermis was disorganised and releasing secretory contents on the surface through small pores. Appearance of huge quantity of biogenic semi-hexagonal plate like crystals (guanine platelets) on the skin surface of the body was the most significant observations during UV-B radiation. In the developmental phases the eyeball showed shrinkage loosing normal regular concave structure and to become a dome-shaped one. The supportive connective infoldings became loosened. The choroid coat displayed deformities and the iris deformed the pupil. The fibroblast on the epithelium and melanocytes depicted dispersed arrangement. The pairs of ventral barbels near the mouth depicted the presence of taste buds that became severely damaged exposing the sensory as well as neuroepithelial cells. Compact regular arrangement of the SECs was completely destroyed leaving long and deep channels inbetween them; the disintegrated concentric MRs also showed a mass.
本研究强调了在实验室条件下，用紫外线-B 辐射（280-320nm）照射呼吸空气的鲶鱼（Clarias batrachus，Linn. 1758）的卵，在 5、10 和 15 分钟/天的时间框架下，剂量为 4.07×10J/photon/m，持续 5 天和 10 天，对其皮肤、眼睛、触须和鳍的超微结构（SEM）变化进行了研究。在整个实验期间，通过 PCS Testr 35 多参数测量，水文学参数没有显示出显著变化。形态计量分析显示，在延长的 10 天暴露期内，卵的大小和重量由于特定生长率（SGR）而减少。在 3 个时间框架下，5 天和 10 天的体重 SGR 值分别为 17.12%、12.52%、11.46%和 9.09%、6.43%、6.09%，这表明随着暴露天数的增加呈下降趋势。在鲶鱼的皮肤中，分层上皮细胞和粘液细胞的紧密规则排列变得扭曲，微脊和双脊结构显示出破坏和碎裂。身体条纹和微褶皱收缩和肿胀，最终退化形成一团。整个表皮粘液细胞的分布变得杂乱无章，并通过小毛孔在表面释放分泌物。大量生物半六边形板状晶体（尿酸盐晶体）出现在身体表面是紫外线-B 辐射时最显著的观察结果。在发育阶段，眼球收缩，失去正常的规则凹面结构，变成穹顶状。支持性结缔组织内陷变得松弛。脉络膜层显示出畸形，虹膜使瞳孔变形。上皮细胞上的成纤维细胞和黑色素细胞呈现分散排列。靠近嘴的成对的腹须显示出味觉感受器严重受损，暴露了感觉和神经上皮细胞。SEC 的紧密规则排列完全被破坏，它们之间留下长长的深通道；解体的同心 MR 也显示出一团。
