The timing of re-institution of good blood glucose control affects apoptosis and expression of Bax and Bcl-2 in the retina of diabetic rats.
Hyperglycemia initiates a sequence of events that leads to the development of diabetic retinopathy. We explored the effect of re-institution of good blood glucose control on apoptosis and apoptosis related genes (Bax and Bcl-2) in the retina of diabetic rats. Fifty male Wistar rats randomly divided into five groups : normal control group (CON), diabetic rats with high blood glucose levels for 8 months group (DM) ,diabetic rats with good blood glucose control for 8 months group (DM(1)),diabetic rats with poor blood glucose control for 2 month followed by good blood glucose control for six additional months group (DM(2)), rats with poor blood glucose control for 4 months followed by good blood glucose levels for four additional months group (DM(3)). Expression of Bax and Bcl-2 in the retina was studied by immunohistochemistry and the apoptotic cells were stained using the TUNEL method. The apoptotic cell, expression of Bax and Bcl-2 and the ratio of Bax to Bcl-2 in the retina was increased in DM group compared with normal rats' (P < 0.01). There was no significant difference in apoptotic cells and the ratio of Bax to Bcl-2 between DM(1) group and CON group. The number of TUNEL positive cells and Bax to Bcl-2 ratio was partially reversed in DM(2) group. But glucose control had no effect on the apoptotic cells and the expression of Bax and Bcl-2 in DM(3) group. There was a positive correlation between apoptotic cells and Bax/Bcl-2 ratio in the retina (r = 0.808, P < 0.01). Good blood glucose control at early stage can decrease the number of apoptotic cells in the retina; the decreased apoptosis is correlated with the down-regulation of Bax to Bcl-2 ratio.
Gao
Xin-Yuan
XY
Department of Endocrinology, The First Clinical Hospital of Harbin Medical University, Harbin, China.
Kuang
Hong-Yu
HY
Zou
Wei
W
Liu
Xiao-Min
XM
Lin
Hong-Bin
HB
Yang
Yi
Y
D000818:Animals; D017209:Apoptosis; D001786:Blood Glucose / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000097:blood* / Q000473:pathology*; D006442:Glycated Hemoglobin / Q000378:metabolism; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000378:metabolism* / Q000473:pathology*; D013997:Time Factors; D051028:bcl-2-Associated X Protein / Q000378:metabolism*
D001786:Blood Glucose; D006442:Glycated Hemoglobin; D051028:bcl-2-Associated X Protein