Objective：To observe the expression of gene and protein l evel of unfolded protein, glucoseregulated protein 78 (GRP78), after retinal d etachment (RD); to find out the relationship between UPR and the cell damage after RD. Methods：Eightyeight Wistar rats were divided into 2 groups: con trol group (11 rats) and RD group (77 rats). In RD group, subretinal injection with 10 mg/ml hyaluronic acid sodium was performed on the left eyes of the rats t o set up RD model, and the left eyes and retinal tissue were collected 1/2 day, 1 day, 2, 4, 8, 1 6 and 32 days after RD; there were 11 rats in each subgroup. The expression of G RP78 mRNA in retina tissue was detected by semiquantitative reverse transcript i on polymerase chain reaction (RT－PCR), the expression of GRP78 protein level wa s detected by Western blotting, and the distribution of GRP78 in each retinal lay er was observed by immunofluorescence labeling method and confocal microscopy. Results：The expression of retinal GRP78 mRNA significantly in creased in 1/2 day , 1 day, 2, and 4 days subgroups after RD (Plt;0.05). The expression of GRP7 8 protein significantly increased in each subgroup after RD compared with which in the control group, and reached the peak in 8, 16, and 32 days subgroups. The expres sion of GRP78 protein was detected in all of the retinal layers after RD. Conclusion：The protection mechanism of UPR starts up after RD, and l eads the correc t pucker of the protein and reduces cellular injury by upregulating the expres s ion of GRP78, which provide the theoretic basis for reducing the cellular injury and improving the visual function in patients with RD.
Objective To investigate the effect of hypoxia on expressions of erythropoietin（EPO）mRNA and protein in retinal Muuml;ller cells cultured in vitro. Methods Retina tissues from the new-born Wistar rats were dissected into cell suspension after digested by pancreatin.Muuml;ller cells were separated and purified by mechanical concussion and blowing and striking method.The expression of EPO mRNA and protein under the condition of hypoxia was detected by semi-quantitative reverse transcriptase（RT）-polymerase chain reaction（PCR）and immunocytochemical method. Results Retinal Muuml;ller cells were cultured successfully，95% of which were positively stained by glial fibrillary acidic protein（GFAP）.Positively stained EPO protein was located in the cytoplasm and protuberance.The expression of EPO mRNA and protein was faint in the normal retinal Muuml;ller cells，but increased obviously and time-dependently after hypoxia. Conclusion Expression of EPO mRNA and protein increases in Muuml;ller cells after hypoxia，which may be one of the protective factors for the nerves in anoxic retinopathy. (Chin J Ocul Fundus Dis, 2006, 22: 196-199)
Objective To verify whetheriris pigment epithelial cells(IPECs)possess the similar potential of specific phagocytosis to retinal outer segments(ROS) with retinal pigment epithelialcells(RPECs). Methods IPESc were isolated from neonatal bovines with Hu's method,and were cultured.The cultured cells were identified by immunohistochemical methods with antibodies to cytokeratin and s-100.Total RNA of IPECs was extracted by Trizol.The specific primers for mannose-receptor andbeta;-actin were designed according to their sequence from Genbank.The mRNA expression of these proteins in the IPECs was analyzed by reverse transcription polymerase chain-reaction (RT-PCT).Results The Cultured IPECs have no contamination of other cells .The extracted RNA was ideal and had no degradation.RT-PCR analysis showed that mannose-receptor's mRNA was expressed in cultured IPECs in vitro.ConclusionCultured IPECs may express the mannose-receptor,and may have similar potential of phagocytosis to ROS with REPCs.
ObjectiveTo quantitatively determine the levels of type Ⅰ and type Ⅱ collagen mRNA in the intervertebral disc cartilage endplate of injured animal model, and to clarify the cytological function of intervertebral disc chondrocytes during fibrosis repair after intervertebral disc injury.MethodsForty healthy New Zealand rabbits were randomly divided into fibrosus puncture group, upper cartilage endplate single puncture group, upper and lower cartilage endplate multiple puncture group, and sham group. Two experimental animals were randomly selected from each group on the 2nd day, and the 2nd, 8th, 12th, and 24th week after the animal modeling operation to obtain intervertebral disc specimens. The levels of type Ⅰ collagen and type Ⅱ collagen in cartilage endplate cells of the intervertebral disc were determined by reverse transcriptase polymerase chain reaction (PCR). RNA was extracted from the endplate of the intervertebral disc, and the RNA concentration and the ratio of RNA concentration to protein concentration were determined by nucleic acid analyzer. Reverse transcription was performed by Revertaid M-Mulv reverse transcriptase, type Ⅰ and type Ⅱ collagen primers were designed to establish a PCR reaction system, 2% agarose gel electrophoresis (120 V, 40 min) was prepared by using 0.5×TBE electrophoresis buffer. The amplification results were observed under ultraviolet light, and the gray values of different electrophoresis bands were determined.ResultsThe level of type Ⅰ collagen mRNA in each operation group showed a progressive increase after 8 weeks, and the magnitude of the increase was related to the degree of injury. The level of type Ⅱ collagen mRNA showed a transient increase in the fibrosis puncture group and the upper endplate single-puncture group in the first two weeks after the endplate punctures were completed, and then began to decline progressively; in the multiple puncture group, it showed a downward trend from the beginning of the operation. ConclusionsThe synthesis of type Ⅰ collagen in chondrocytes of the injured nucleus pulposus tissue continues to increase with time, while the synthesis of type Ⅱ collagen begin to decrease progressively after a small increase. The formation and change of type Ⅰ and type Ⅱ collagen in injured intervertebral disc chondrocytes are different from natural degeneration.