To examine the morphological changes, all the mice were weighed every two weeks. As shown in Figure 2A, the average BW gain of the 1000 mg nCu/l-treated mouse group was not only elevated, but also significantly declined as compared to control group during the 8 weeks treatment, whereas changes in BW gain of the other four mouse groups including nCu-20, nCu-1000, and 2 mg nCu/l-treated mice as well as control were similar to each other (data not shown). Consequently, nCu treatment at dose of 1000 mg/l resulted in average weight loss of mice.