Tetramethylpyrazine protects mice retinas against sodium iodate-induced oxidative injury

To observe the effects of tetramethylpyrazine (TMP) on mice retinas injured by sodium iodate (NaIO₃).

Male mice (n = 45) were randomly divided into three groups: the control group (Group C), the NaIO₃-degenerated group (Group I), and the TMP-treated group (TMP group). The Group I mice were intraperitoneally injected with 35 mg/kg NaIO₃. The Group C mice were injected with similar volumes of PBS. The TMP group mice were intraperitoneally injected with 80 mg/kg TMP starting 24 h after NaIO₃ administration once a day for 14 days. Fundus photography, optical coherence tomography (OCT), electroretinography (ERG), hematoxylin and eosin (H&E) staining, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, and western blotting were used to assess the effects of TMP on mice retinas at day 3, 7, and 14 after NaIO₃ administration.

TMP effectively prevented the decrease in the thicknesses of the retinas and the outer nuclear layer (ONL), and effectively alleviated the functional decline in the retinas after NaIO₃ administration. TMP significantly decreased the number of TUNEL-positive cells in retinas. In addition, TMP rapidly increased the expression of Nrf2 and HO-1 and decreased BAX expression in mice retinas after NaIO₃ injection.

TMP alleviates morphological and functional retinal damage in mice exposed to NaIO₃ and reduces retinal apoptosis.