ournal o J. Trace Elements Med. Biol. 14, pp. 205 - 209 April 2001 n Medicine and Biolog! Element concentrations and cataract: an experimental animal model © 2000 Urban & Fischer L. Ciaralli, R. Giordano 1, S. Costantini, A. Sepe, R Cruciani*, A. Moramarco*, B. Antonelli* and C. Balacco-Gabrieli* Istituto Super±ore di San±t±,Applied Toxicology Department, Viale Regina Elena 299, 00161 Rome, Italy *11 Divisione Clinica Oculist±ca, Institute of Ophtalmology, University "La Sapienza", Viale del Policlinico, 00161 Rome, Italy Summary The determination of inorganic ions in cataractous human lenses has been the subject of several investigations; neverthe- less, few studies have been concerned with trace element con- tents in lenses, and data are sometimes contradictory. An animal experimental model of induced cataract is here proposed with the aim of evaluating the changes of Ca, Na, K, Cu and Zn concen- trations. The cataract was produced by an Nd: YAG Laser treat- ment of the right eye of sexteen male rabbits. The determination of the elements was performed by atomic absorption spectrome- try (both flame and flameless methods) after an acid digestion of samples. Compared with the results obtained in left lenses used as a control (Ca 14.4,+5.7 mg/kg d.w.; Na 1.3_+0.5g/kg d.w.; K 9.9,+1.1 g/kg d.w.; Cu 0.24-+0.09 mg/kg d.w.; Zn 24.8_+2.3 mg/kg d.w.), the mean concentration values of opaque lenses showed some significant changes for Ca, Na, and Cu (Ca 123.7_+106,6 mg/kg d.w.; Na 4.5_+4.3g/kg d.w; Cu 0.43_+0.21 mg/kg d.w.). Po- tassium showed a tendency to decrease, and zinc to increase. Positive correlations were found between calcium and sodium both in controls (r= 0.73, p<0.001 ) and in treated lenses (r= 0.87, p< 0.0001). An inverse correlation between Ca and K confirmed the tendency of potassium to decrease. Keywords: Human lenses, cataract, trace elements. (Received December i998/October 1999) Introduction The determination of inorganic ions such as Ca, K, Mg and Na in clear and cataractous lenses has been the subject of sever- 1To whom correspondence should be addressed, al studies (1-3) carried out with the aim of evaluating the role these ions have in the mechanism of cataractogenesis. The data showed that the formation of senile cataract is strictly associat- ed with the impairment of the permeability of the eye lens mem- brane, resulting from the accumulation of calcium and sodium ions, and the loss of potassium (4-5). These observations have been also confirmed in a previous study by the present authors (6). The information reported in literature regarding the levels of trace elements in cataractous lenses are in part contradictory and the effective role of inorganic elements still needs to be clarified. For this reason, the involvement of various metals in cataract formation is currently an area of intensive research. The aim of the present work was to evaluate whether an an- imal model of induced cataract would cause changes in the min- eral content of lenses. This would represent a good way of stud- ing the behaviour of the elements in cataractous lens, overcom- ing at the same time ethical aspects and the difficulty of obtain- ing normal human lenses to be used as controls. Therefore, treatment with a laser was used to produce a lenticular photof- ragmentation and, consequently, large lens opacities; the right eye of each rabbit was treated, while the left eye was preserved clear as control. The concentration of Ca, Na, K, Cn and Zn was measured both in clear and cataractous eye lenses by flame (Ca, Na, K, Zn) and graphite furnace (Cu) atomic absorption spec- trometry (FAAS and GFAAS, respectively). The elements in- vestigated were chosen because of their role in ocular tissues. Role of Ca, Na, K, Cu and Zn in the eye Calcium plays an important role in muscular contraction, participating in mechanisms which involve numerous substanc- es, such as myosin and aetin (7). These two compounds have