Morphological, biochemical, and histopathological postmortem ocular indices following subchronic exposure to cadmium and/or lead in a rabbit model

Abstract

Cadmium (Cd) and lead (Pb) are ubiquitous environmental pollutants. There is a dearth of information on the mutual interaction between the antemortem metal intoxication and the postmortem changes of the eye. Thus, this study aimed to follow the morphological, biochemical, histopathological ocular perturbations and the retinal DNA damage up to 8 h postmortem (PM) in Cd and/or Pb intoxicated rabbits. The animals orally received 5 mg Cd Cl₂/kg bw and/or 12.5 mg lead acetate/kg bw for 30 consecutive days. At time of death, eye pupil of different groups had a normal diameter except Pb-intoxicated group had marked myosis. After 8 h of death, different rabbit's eye corneas appeared wrinkled and covered with thin white cloud while the pupils were in the mydriatic stage. Up to 8 h PM, the individual exposure to Cd or Pb resulted in a significant elevation in GGT, urea, K, DNA damage and obvious retinal lesions. However, their co-exposure evoked an antagonistic outcome. The eye of Cd and/or Pb intoxicated rabbit showed mildly degenerated tissue of cornea and sclera and the presence of irregular eosinophilic droplets of variably size in the lens with a gradual degeneration and vacuolization in the different cell layers of retina especially ganglion up to 8 h PM. Also, by increasing post mortem interval (PMI), retinal DNA damage in Cd and/or Pb intoxicated group significantly decreased. It is concluded that Cd and/or Pb intoxication induced ocular alterations which retain the same trend in correlation with PMI as natural deaths except for the retinal DNA damage. Also, the simultaneous exposure to Cd and Pb evoked an antagonistic outcome in the eye. The findings of the current study should be taken into consideration when estimating PMI in areas with high Cd and/or Pb contamination.