Effect of estrogen on electroretinographic responses in streptozotocin-induced diabetic female rats.
The aim of this study is to investigate the effects of estrogen on functional changes in the retinas of streptozotocin (STZ)-induced diabetic rats by using an electroretinography. Female rats were randomly divided into four treatment groups: (1) Control (sham operation and vehicle administration); (2) STZ (sham operation and STZ administration); (3) OVX (ovariectomy and vehicle administration); and (4) OVX + STZ (ovariectomy and STZ administration). Full-field electroretinograms (ERGs) were recorded before OVX and STZ administration and 4 and 12 weeks after STZ administration. At 4 weeks after STZ administration, although there were no differences in the STZ and OVX groups compared with the Control group, the amplitude of the cone-response was significantly lower in the OVX + STZ group than in the Control group (P = 0.013). At 12 weeks after STZ administration, this response showed a similar tendency in the STZ and the OVX + STZ groups. At 12 weeks after STZ administration, the implicit times of OP3 and OP4 and of the cone-response were significantly delayed in the STZ and OVX + STZ groups (OP3: P = 0.030 and 0.050, OP4: P = 0.0060 and 0.0053, cone-response: P = 0.014 and 0.039), compared with in the Control group. Thus, the retinal functions in STZ-induced diabetic female rats were aggravated by OVX. OVX-induced estrogen deficiency resulted in earlier changes in the amplitudes of cone-response, especially in the diabetes, although this is a transient effect and it is difficult to explain. Recognizing the early neurosensory change would enable a better understanding of the effect of estrogen in the retina.
Drug Safety Laboratory, Drug Safety and Pharmacokinetics Laboratories, Taisho Pharmaceutical Co., Ltd., 403 Yoshino-cho 1, Kita-ku, Saitama-shi, Saitama 331-9530, Japan. h.yamashita@po.rd.taisho.co.jp
Haruhiro
H
Yamashita
Kazunari
K
Sugihara
Chiaki
C
Yamada
Shunsuke
S
Tsutsumi
Yoshinobu
Y
Iwaki
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001835:Body Weight; D002386:Cataract / Q000503:physiopathology; D003316:Corneal Diseases / Q000503:physiopathology; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D004596:Electroretinography; D004967:Estrogens / Q000502:physiology*; D005260:Female; D010052:Ovariectomy; D010053:Ovary / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D012160:Retina / Q000503:physiopathology*
D001786:Blood Glucose; D004967:Estrogens