Pornpen Chaiworakul. Estrogenic effect of phytoestrogen (genistein and Pueraria Mirifica) on rat sciatic nerve regeneration mediated via extracellular signal-regulated kinase (ERK) signaling pathway. Master's Degree(Anatomy). Mahidol University. : Mahidol University, 2006.
Estrogenic effect of phytoestrogen (genistein and Pueraria Mirifica) on rat sciatic nerve regeneration mediated via extracellular signal-regulated kinase (ERK) signaling pathway
Abstract:
Although recovery after peripheral nerve injury is common, it is often slow or
incomplete. Therefore, there has been considerable interest in agents that might
enhance the speed or completeness of nerve regeneration. Current reports indicate that
estrogen (E2) shows neuroprotective and neuropromoting regeneration in the nervous
system. Because of their structural similarity to E2, phytoestrogens may have
therapeutic potential in peripheral nerve injuries which as previously reported to
enhance SFI following sciatic nerve crush in rats. The aim of this study was to
investigate the estrogenic activity of phytoestrogens, genistein and herbal extract
(Pueraria mirifica) on the expression of ERK1/2 and S-100 protein involved in
peripheral nerve regeneration using sciatic nerve crush and transection models in male
Sprague Dawley rats. Protein levels of phospho-ERK1/2 and S-100 protein in distal
segments of sciatic nerve at day 7 after nerve injury were determined by Western blot
analysis. The results demonstrated that genistein and Pueraria mirifica treatment,
similar to estrogen benzoate (E2), caused a significant decrease in the expression of
phospho-ERK1/2 levels in both sciatic nerve crush and transection injuries at day 7.
However, the transected nerves showed high and sustained levels of ERK1/2
phosphorylation. Following treatments, levels of S-100 protein were significantly
decreased both in crushed and transected nerves with respect to the control group
(p<0.05). Furthermore, the estrogenic effect of phytoestrogens was blocked by the ICI
182,780 (estrogen receptor (ER) antagonist). These results suggest that phytoestrogens
could enhance nerve regeneration by interfering with the injury-induced ERK
signaling pathway.