[Apoptosis of retinal capillary cells in diabetic rats and expression of apoptosis-related genes].
OBJECTIVE
To determine the apoptosis of retinal capillary cells in early diabetic rats and observe the expression of apoptosis-related genes (bcl-2, Bax) in retinas of early diabetic rats.


METHODS
40 healthy adult Wistar rats were chosen and randomly divided into four groups: normal control (CON), diabetes mellitus one month (DM1), three months (DM3) and six months (DM6). Diabetic mellitus in rats was induced by streptozotocin (STZ) intraperitoneally. Retinal preparations of blood vessels and paraffin sections were stained by TdT-mediated dUTP nick end labeling (TUNEL) and immunohistochemical (ABC) method respectively and analyzed by computer-picture analytic system on the results of ABC method.


RESULTS
Positive pericyte nuclei labeled by TUNEL were emerged in DM3 and DM6, but positive endothelial cell nuclei only in DM6. No positive reaction was seen in CON and DM1. Chromatin of TUNEL positive nuclei was distributed unequally, showing apoptotic characteristics of ring-like and crescent nuclei. In ABC staining method, two genes' (bcl-2, Bax) proteins were expressed in retinal vessels. Along with the progression of diabetes, the intensity of positive reaction was increased in degrees. Moreover, pigment epithelial cells in DM3 showed Bcl-2 positive reaction that again extended further to inner rod segments and ganglion cells in DM6, while in DM6, Bax was expressed in ganglion cells.


CONCLUSIONS
The nature of pericyte dropout in early diabetic rats is apoptosis that also exists in endothelial cells; the expression of Bax and bcl-2 in retinas of early diabetic rats is enhancing.
Liu
X
X
Department of Anatomy, Jinzhou Medical College, Jinzhou 121001, China.
Xiao
H
H
Qu
W
W
D000818:Animals; D017209:Apoptosis; D002196:Capillaries / Q000737:chemistry* / Q000166:cytology; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism* / Q000503:physiopathology; D005260:Female; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D008297:Male; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D012171:Retinal Vessels / Q000737:chemistry / Q000166:cytology; D051028:bcl-2-Associated X Protein
C494828:Bax protein, rat; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein