Fig 1.
(A). Chemical structure of ZD. (B). Adult C57 mice were fed with ZD-enriched wolfberry extract (ZDE) orally daily for two weeks, during which 40 mg/kg MNU was intraperitoneally injected at 1 week to induce retinal photoreceptor cell degeneration. Then the visual behavior and ERG were tested at 2 weeks after treatment before the animals were sacrificed and the retina collected for immunostaining.
Fig 2.
The ZDE product contains higher ZD than dry wolfberry.
The HPLC chromatograms show the peak of ZD from ZD standard (A), dry wolfberry (B), and the ZDE product (C). The peak time is 27.868, 28.011, and 28.161 mins for ZD standard, wolfberry, and ZDE respectively.
Fig 3.
ZDE improves photoreceptor survival in MNU-injured retina.
(A). Images of retinal sections in full length as C-cup from solvent treated and ZDE (at 9mg/kg) treated MNU-injured mice. Insets showed the enlarged region at 1mm away from the optic never center. (B). Average thickness of ONL of normal control retina and MNU-injured retina after treatment of solvent or ZDE at increasing doses. The number of animals tested is 4, 7, 4, 6, 6 and 3 for control, solvent and 1, 3, 9, 27 mg/kg ZDE respectively. (C). Average number of ONL cell layers (left) and thickness of ONL(right) of normal control retina and MNU-injured retina treated with solvent or 9 mg/kg ZDE at various distance away from the center of optic nerve. ONL, outer nuclei layer; INL, inner nuclei layer; GCL, ganglion cell layer. *, p<0.05, **, p<0.01, ***, p<0.001, one-way ANOVA followed by Dunnett’s multiple comparison test for B and two-way ANOVA test followed by Tukey’s multiple comparison test for C.
Fig 4.
ZDE enhances the retinal light responses of MNU-injured mice.
(A). Example traces of ERG recording from normal control, solvent and ZDE-treated MNU-injured mice. Values on the left show the flash intensity with the unit of cd.s/m2 under either scotopic (i.e. dark adaptation) or photopic (i.e. light adaptation) conditions. Peaks of a- and b-waves were shown in ZDE-treated animals. Note the different scales of control and MNU-injured groups. (B, C). Average amplitudes of a-wave (B) and b-wave (C) for all-flash conditions. *, p<0.05,**, p<0.01; ***, p<0.001, two-way ANOVA test of repetitive measurement followed by Tukey’s multiple comparison test.
Fig 5.
ZDE enhances the visual acuity of MNU-injured mice.
(A). Illustration of the dark-light-transition box. (B). Average percent of time spent in the dark chamber. (C). Illustration of the optomotor system. (D). Average visual acuity of normal mice, solvent and ZDE-treated MNU-injured mice. *, p<0.05, ***,p<0.001, one-way ANOVA test followed by Tukey’s multiple comparison test. N.S., no significant difference.