Protective effects of Chinese herbal medicine Zuogui Pill on retina ganglion cells after optical nerve clipping injury in rats

Abstract

To investigate the protective effects of Zuogui Pill (ZGP), a compound Chinese herbal medicine, on retina ganglion cells (RGCs) in rats after optical nerve clipping injury. Optic nerves in Sprague-Dawley rats were crushed intraorbitally at 2 mm behind eyeball by using a forceps with a 140-gram chucking power for 30 s to induce unilateral injured model. The injured rats were fed with ZGP (ZGP group, 4.0 g/kg body weight each day) and equal volume of normal saline (injury group) respectively. Morphological changes in the retina were observed and the RGCs were quantified in the specimens. Nestin and glial fibrillary acidic protein (GFAP) expressions in the retina were detected by immunohistochemical fluorescence staining at different time points after nerve injury. After optical never crushing, the thickness of retina and the number of RGCs were significantly decreased in injury group as compared with the normal group. Nearly 50% of the total RGCs were disappeared at the 4th week in the injury group. The expression levels of nestin and GFAP in the retina were markedly increased after optical never crushing at the 2nd week and this lasted to the 8th week, and gradually decreased to the normal level at the 16th week. In contrast, the arrangement of retinal cells was regular in the ZGP group, and the number of survival RGCs was greater than that of the injury group. Meanwhile, the nestin and GFAP expressions in retina were significantly enhanced as compared with the injury group at all time points. ZGP may have protective effects on rat optic nerve and RGCs after contusion by promoting the nestin and GFAP expressions in Müller cells of the retina.