Changes of the Inducible Heat Shock Protein 70 mRNA Level in Rat Retina After Ischemia and Reperfusion

Abstract

The heat shock protein 70 (HSP-70) mRNA level was evaluated in Long Evans rat retinas after ischemia and after reperfusion following ischemia. Retinal ischemia was induced by ligation of the optic nerve and vessels. Rats were sacrificed after 90 min of ischemia or 120 min of reperfusion following ischemia. Retinas were dissected. Total mRNA was extracted and inducible HSP-70 (iHSP-70) gene expression was analyzed by quantification of transcripts using an RT-PCR assay. Results were expressed in arbitrary units as a ratio of the optical density of iHSP-70/β-actin electrophoretic bands. iHSP-70 gene expression was 0.220 ± 0.027 (n = 5), 0.502 ± 0.045 (n = 5) and 0.468 ± 0.032 (n = 5) for the sham-operated, ischemia only and ischemia and reperfusion groups, respectively. There was a statistically significant difference between the control and ischemia groups, and between the control and ischemia and reperfusion groups (p < 0.001), suggesting a rapid HSP-70 mRNA expression of the retina due to an ischemic injury.

Protective Effect ofHeat Shock Proteins 70.1and70.3on Retinal Photic Injury after Systemic Hyperthermia

“…[24][25][26] In ocular tissue, especially the retina, hsp70 is a major stress protein. Hsp70 in mice is composed of the end products of hsp70.1, 70.2, and 70.3 [18][19][20][21] and has retinal protective effects against various stresses.…”

“…29 However, mRNA expression is strong evidence of protein production. Because the hsp70s from hsp70.1 and hsp70.3 are highly homologous, [18][19][20][21] it is very difficult to distinguish between them at the protein level. Therefore, the production patterns of hsp70s from hsp70.1 and hsp70.3 were evaluated indirectly from the changes in mRNA expression.…”

Induction of heat shock proteins 27 and 72 in retinal ganglion cells after acute pressure‐induced ischaemia

“…HSPs 25/27 are controversial in the literature; HSP 25 is also reported to be highly specific for the rodent form and does not cross‐react with other HSPs, including primate HSP 27 31 . Many other laboratories have investigated HSP 27 in rats 18,20,22,27,32 . Lewden showed increased HSP 70 mRNA levels by quantification of transcripts using an RT‐PCR assay after 90–120 min ischaemia induced by ligation of the optic nerve, suggesting a rapid HSP‐70 mRNA expression in the retina 32 .…”

Heat Shock Protein 70 Expression Increased in Rabbit Müller Cells in the Ischemia-Reperfusion Model

“…In the retina, a protective role for HSPs against lightinduced retinal injury has been shown in vivo [18], and induced HSP70 increases tolerance to hypoxia and exocytotoxicity in cultured rat retinal ganglion cells [19]. Recently, it has been shown that the HSP70 mRNA level was increased in rat retinas by ischemia-reperfusion [20], but it was still unclear in which cells HSP70 is expressed in this model. Our data clearly demonstrated that HSP70 was significantly increased by ischemia-reperfusion in rabbit retinas and expressed mainly in the Müller cell.…”