The effects of caffeic acid phenethyl ester on retina in a diabetic rat model

Abstract

Purpose

We aimed to investigate the effect of caffeic acid phenethyl ester (CAPE) on retinal apoptosis and oxidative stress parameters in streptozotocin (STZ) induced diabetic rat model.

Methods

This study included 3 groups; control, STZ, and STZ + CAPE. The rats in STZ, and STZ + CAPE groups were injected with STZ (35 mg/kg, i.p.) for induction of diabetes. In the STZ + CAPE group, 10 µmol/kg of CAPE were intraperitoneally injected for 4 weeks. Control and STZ groups were given only intraperitoneal vehicle (saline). Rats were anaesthetized and sacrificed on the 4th week of the experiment. Total anti-oxidant status (TAS), and total oxidant status (TOS) were measured on the dissected retinal tissues. Oxidative stress index (OSI) was also calculated. Fellow eyes were used for histopathologic evaluation with caspase-3 and matrix metalloproteinase-2 (MMP-2) and MMP-9 evaluation.

Results

TAS levels were similar between groups (p = 0.71). However, CAPE treatment prevented the elevation of the TOS in the STZ + CAPE group compared to the STZ group (30.93 ± 9.97 vs 61.53 ± 24.7 nmol H₂O₂ Eq/mg protein, p = 0.007). OSI was also significantly lower in the STZ + CAPE group than that of the STZ group (20.01 ± 5.87 vs. 37.90 ± 14.32, respectively, p = 0.007). Retinal caspase-3 staining, MMP-2 and MMP-9 scores were not different between groups (p > 0.05 for all).

Conclusion

The present study demonstrated that CAPE treatment may decrease the oxidative stress in the retina in STZ induced diabetic rat model. However, apoptosis was not observed in the retina. The retinal apoptosis cannot be shown probably due to a shorter period of diabetes.

Keywords:

• Anti-oxidant capacity
• caffeic acid phenethyl ester
• caspase-3
• diabetes mellitus
• diabetic retinopathy
• oxidative stress
• streptozotocin

Disclosure statement

No potential conflict of interest was reported by the author(s).