Protective effect of hepatocyte growth factor against degeneration of the retinal pigment epithelium and photoreceptor in sodium iodate-injected rats.
OBJECTIVE
To investigate the possible protective effect of hepatocyte growth factor (HGF) against degeneration of photoreceptors and retinal pigment epithelium (RPE) in vivo.


METHODS
Sprague-Dawley (SD) rats received an intravitreal injection of HGF in the right eye. The left eye was injected with vehicle as a control. Two days after the intravitreal injections, rats were administered 40 mg/kg of sodium iodate (NaIO3) intravenously. Scotopic ERGs were elicited by different stimulus intensities with a maximum luminance of 0.84 log cds/m2. To evaluate RPE function, the azide response was evoked by intravenous injection of 0.1 mg sodium azide. These electrophysiological measurements were conducted on days 4, 7, 14, and 28 after the NaIO3 injections. After recording ERGs or azide response, animals were sacrificed for quantification of the histological change and immunohistochemical analysis using antibodies against RPE 65.


RESULTS
The threshold for the scotopic b-wave was significantly lower in HGF-treated eyes than in untreated control eyes (p < 0.005), and maximum b-wave amplitudes (Vbmax) were significantly larger in HGF-treated eyes (p < 0.05) across all experimental time points after NaIO3 injection. Azide response amplitudes were significantly larger in the HGF-treated eyes than in the untreated eyes (p < 0.05). The structure of the outer retina was preserved to a greater degree in the HGF-treated eyes than in the untreated eyes (p < 0.05). Immunohistochemical analysis demonstrated that irregular alignment of the outer nuclear layer was confined to the retinal area that was not stained with RPE 65.


CONCLUSIONS
Our results indicated that an intravitreal injection of HGF provided significant protection against degeneration of the photoreceptor and RPE induced by systemic administration of NaIO3. This suggests that HGF could be used as a therapeutic agent for degeneration of photoreceptors as well as RPE.
Ohtaka
Kouji
K
Department of Ophthalmology, Iwate Medical University School of Medicine, Iwate, Japan.
Machida
Shigeki
S
Ohzeki
Takayuki
T
Tanaka
Michiko
M
Kurosaka
Daijiro
D
Masuda
Tomoyuki
T
Ishii
Takehisa
T
D000818:Animals; D002352:Carrier Proteins; D004596:Electroretinography; D005136:Eye Proteins / Q000378:metabolism; D017228:Hepatocyte Growth Factor / Q000627:therapeutic use*; D007267:Injections; D007452:Iodates / Q000633:toxicity*; D008297:Male; D020419:Photoreceptor Cells, Vertebrate / Q000187:drug effects* / Q000502:physiology; D010857:Pigment Epithelium of Eye / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012162:Retinal Degeneration / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D019810:Sodium Azide / Q000633:toxicity; D014822:Vitreous Body; D019745:cis-trans-Isomerases; D000099178:Retinoid Isomerohydrolase
D002352:Carrier Proteins; D005136:Eye Proteins; D017228:Hepatocyte Growth Factor; D007452:Iodates; D019810:Sodium Azide; D019745:cis-trans-Isomerases; D000099178:Retinoid Isomerohydrolase; C032285:sodium iodate