Apoptosis and the changes of Na+ and K+ contents in retina of rats with diabetes mellitus

Liuping TANG; Jianfeng HE; Juan DU; Xiangrong LI; Yanxia HUANG

ABSTRACT

BACKGROUND:

Diabetic retinopathy is a commonly chronic-vascular complication in a course of diabetes mellitus (DM), and its relation with apoptosis and changes of ion level needs to be proved.

OBJECTIVE:

To observe apoptosis and changes of Na+ and K+ contents in retinal tissue of DM rats.

DESIGN:

Randomized controlled study.

SETTING:

Department of Ophthalmology, Liuzhou Municipal People's Hospital.MATERIALS The experiment was completed at the Department of Ophthalmology, Liuzhou Municipal People's Hospital. A total of forty adult male Wistar rats, aged 20 months, weighing 320-350 g, were provided by Animal Center of Medical College Affiliated to Sun Yat-sen University.

METHODS:

Forth Wistar rats were randomly divided into control group and experimental group with 20 in each group. Streptozotocin was used to induce DM in the experimental group. Apoptosis and changes of Na+ and K+ contents in retinal tissue were measured on the 4th, 6th, 12th and 16th weeks after DM onset. Rats in the control group were injected only with the same volume of citrate buffer solution. Then, correlations on the aspect of fasting blood glucose (FBG), hemoglobin glycosylation (HbAlc), Na+ and K+ contents and DM course were analyzed between the two groups.MAIN OUTCOME

MEASURES:

① Na+ and K+ contents; ② FBG concentra tion and HbAlc level; ③ changes of apoptosis; ④ correlations among markers.

RESULTS:

Apoptosis could be detected in retinal tissue in the experimental group at 4 weeks after DM onset, and with course elongating, level of apoptosis was aggravated gradually. Na+ concentration was increased in retinal tissue, but K+ concentration was decreased (P ＜ 0.01 or 0.05). Levels of apoptosis in retinal tissue in the experimental group were positive correlation with FBG concentration, HbAlc level, Na+ content and DM course (r=7.584, 7.844, 7.369, 6.246; P ＜ 0.01); however, they were negative correlation with K+ content in retinal tissue (r=7.658, P ＜ 0.01).

CONCLUSION:

There are apoptosis and abnormal Na+ and K+ contents in retinal tissue of DM rats. Moreover, these changes may be one of pathological bases of diabetic retinopathy.