Neuroprotective Effects of Garcinia kola and Curcumin on Diabetic Transected Sciatic Nerve

Abstract

The growing interest in peripheral nerve regeneration and developing post-traumatic repair methods under diabetes was the impetus for this study, which aims to investigate the effect of curcumin and Garcinia kola (GK) on the transected and diabetic sciatic nerves. Thirty-five male Wistar albino rats were used. The animals were divided into five groups; each consisted of seven rats. The sciatic nerve was transected in all groups of rats except the control (Cont) group, which underwent no treatment. In the transected animals, a 10 mm nerve stump was removed from the 2 cm distal to the sciatic notch. The external jugular vein was used as a conduit to repair the gap between the two ends of the sciatic nerve. Diabetes was induced in the transected + diabetes mellitus (T + DM), the transected + diabetes mellitus + GK (T + DM + GK), and the transected + diabetes mellitus + Curcumin (T + DM + Cur) groups except for the sham group. A dose of 300 mg kg-1 d-1 of curcumin dissolved in olive oil was administered to the T + DM + Cur group (via oral gavage every day for 28 d) and 200 mg kg-1 d-1 of GK to the T + DM + GK group (via oral gavage every day for 7 d). All animals were sacrificed after three months. Stereological analysis and functional and microscopic evaluations were done to evaluate the sciatic nerve regeneration and function. In the T + DM + GK and the sham groups, the number of axons increased. A slight improvement in the axonal area in the T + DM + Cur and the sham groups was also observed, and an increase in the myelin sheath thickness was found in the T + DM + GK and the sham group. When the SFI test results were evaluated, it was seen that GK had a stronger effect than curcumin in terms of functional regeneration. Additionally, no significant difference was observed between T + DM and Cont groups when the electrophysiological results were examined. The study showed GK's efficiency in treating diabetic peripheral nerve regeneration.