Agirdir Bülent V, Bilgen Ibrahim, Dinc Oktay, Ozçağlar Hasan U, Fişenk Firat, Turhan Murat, Oner Gülsen
Department of Otorhinolaryngology, Faculty of Medicine, Akdeniz University, Antalya, Turkey.
Biol Trace Elem Res. 2002 Aug;88(2):153-63. doi: 10.1385/BTER:88:2:153.
Cadmium, which has adverse effects on many physiological systems, is an important environmental pollutant. Our previous experimental study showed that cadmium also has a dose-dependent deleterious effect on the auditory system in rats. Because zinc reverses cadmium cytotoxicity in many systems, we investigated the possible preventive effect of a zinc-enriched diet given isochronally on cadmium-induced hearing loss in rats. Fifty-four male rats were divided into three equal groups. Control rats were fed normal rat food and tap water, whereas the cadmium group was subjected to 15 ppm cadmium-containing water as CdCl2. The third group received 15 ppm CdCl2 and food enriched with 200 ppm zinc as ZnSO4 for 30 d. On d 30, eight animals from each group were used for the measurement of kidney functions. In the remaining animals, hearing functions were measured by auditory brainstem response and distortion product otoacoustic emission. Blood cadmium increased from 1.87+/-1.69 to 6.08+/-2.62 microg/dL and elevated cadmium contents of ear ossicles and kidney cortex were associated with a decreased glomerular filtration rate in rats subjected to high cadmium. A zinc-enriched diet obviously reduced cadmium accumulation in the kidney and prevented the nephrotoxicity. Our data indicated that cadmium-induced ototoxicity seems to be partially zinc preventable and zinc addition to diet without altering cadmium content in ear ossicles may help to prevent cadmium-induced hearing loss.
镉是一种重要的环境污染物，对许多生理系统都有不良影响。我们之前的实验研究表明，镉对大鼠听觉系统也有剂量依赖性的有害作用。由于锌在许多系统中能逆转镉的细胞毒性，我们研究了同步给予富含锌的饮食对镉诱导的大鼠听力损失的可能预防作用。54只雄性大鼠被分成三组。对照组大鼠喂食正常大鼠食物和自来水，而镉组大鼠饮用含15 ppm氯化镉（CdCl2）的水。第三组大鼠饮用含15 ppm CdCl2的水，并喂食富含200 ppm锌（硫酸锌）的食物，持续30天。在第30天，每组选取8只动物测量肾功能。其余动物通过听性脑干反应和畸变产物耳声发射测量听力功能。高镉暴露大鼠的血镉从1.87±1.69微克/分升增加到6.08±2.62微克/分升，耳小骨和肾皮质中镉含量升高与肾小球滤过率降低有关。富含锌的饮食明显减少了肾脏中的镉蓄积，并预防了肾毒性。我们的数据表明，镉诱导的耳毒性似乎部分可被锌预防，在不改变耳小骨中镉含量的情况下在饮食中添加锌可能有助于预防镉诱导的听力损失。
