The Morphological Studies On The Müller Cells Of Retina In Normal And Diabetic Rat

Objective: 1. To observe the morphology of the Müller cells of retina in normal rat and the difference between Müller cells and the neurons in the different layers of the retina.To explore the function of the Müller cells by means of morphology. 2.To study the morphological changes and the malfunction of the Müller cell in streptozotocin (STZ) diabetic rats. To investigate the pathological mechanism of the Müller cell in the effect on the course of diabetic retinopathy.Method: 1. To observe the fundus by ophthalmoscopy, and to study the morphology of the Müller cell of the normal retina by means of light microscopy and transmission electron microscope(TEM), respectively. 2,Diabetes was induced in rats by intraperitoneal injection of 75 mg/kg of streptozotocin (STZ). Age-matched rats raised under similar conditions served as control. By the 4 weeks,8 weeks,12 weeks,24 weeks of diabetes, we observed the morphological changes of the retina.,especially the Müller cell, through the technique of ophthalmoscopy , light microscopy and transmission electron microscope(TEM).Result: 1,Ophthalmoscopy: At the end of 12 weeks, we couldn't find the diabetic retinopathy such as the microaneurysm,bleeding point,hardness effusion or cottonwool patches and so on . The fundus couldn't be observe because of the catract by the 24 weekend of diabetes. 2,Light microscopy:Changes,such as nerve fiber swelling and loose structure in the nerve fiber layer,inner plexiform layer,external plexiform layer,occurred in the STZ-induced diabetic rats. We found vacuolization in the inner nuclear layer at the end of 12 weeks of the diabetic rats.Retinal vascular injury couldn't be found even at the end of 24th week of the diabetic rats. 3,TEM: Several mitochondria of the Müller cell became swelling,crest shorting or disappearing by the 4 weeks of diabetes.There are increasing mitochondria which is swelling with the development of the diabetic especiallly in the nerve fiber layer and ganglion cell layer; secondly , inner plexiform layer and external plexiform layer. We did not found the typical changes of the retinal vascular,such as clausura or narrow. vascular endothelial cell and perithelial cell didn't appear obviously abnormal within the 24 weeks.Conclusion: 1,Most of müller cell cytoplasm is in the nerve fiber layer and ganglion cell layer .2,The ultrastructral changes of müller cells are earlier than the the ultrastructral changes of vascular endothelial cells and perithelial cells in the diabetic ratina. 3,The ultrastructral changes of müller cells are most obvious in the nerve fiber layer and ganglion cell layer . 4,The morphological changes of Müller cells become more obvious with the development of the diabetes.