Beneficial Effect of (‐)‐epigallocatechin‐3‐gallate (EGCG) on Sciatic Nerve Crush Injury: Stereological analysis

Abstract

The neuroprotective effect of EGCG on sciatic nerve crush injury is associated with significant neurobehavioral recovery (Renno et al. 2014). In this study, we examined the histological changes in the sciatic nerve after crush injury following EGCG treatment. The mean cross sectional area of the axon showed a significant increase in the EGCG treated group starting at week 4 and continued up to week 8 compared to CRUSH animals. However, axon area remained much smaller in CRUSH+EGCG and CRUSH groups compared to SHAM and NAIVE animals. The number of axons per unit area was significantly decreased in CRUSH+EGCG and CRUSH groups compared to control. The CRUSH group displayed a significant increase in total small and thinly myelinated axon number at week 6 and 8 post‐injury. ECGC treated animals showed a significant decrease in the total myelinated axon numbers. CRUSH+EGCG group showed a significant increase in myelin thickness in the distal sciatic nerve segment at week 4 till week 8 compared to CRUSH animals. EGCG treatment significantly increased the fiber diameter to axon diameter (F/A) ratio and the myelin thickness to axon diameter (M/A) ratio starting at week 2 post sciatic nerve injury compared to CRUSH animals. EGCG has profound positive effect on the myelinated axons; increase in the axon area, myelin thickness, F/A ratio and M/A ratio. In summary, quantitative stereological evaluation revealed significant histomorphological evidence of neuroregeneration in the sciatic nerve of CRUSH+EGCG rats compared to control groups between 2 and 4 weeks postoperatively. The morphometric data analysis supports our hypothesis that EGCG treatment stimulates regeneration of myelinated axons and minimizes histomorphological alterations caused by crush injury of sciatic nerve.This work was supported by Kuwait University Research Administration (grant No. MA01/11).