Purpose To establish orthotopic heterotransplanted model of retinoblastoma(RB)into the vitreous cavity of nude mice for experimental studies of gene therapies in vivo. Methods To prepare the concentrated cell suspensions of human RB cell line HXO-Rb44 and inject them into the vitreous cavities of 10 nude mice(20 eyes).The experimental mice were randomly divided into 2 groups:the first group,5 mice (10 eyes) were injected with 5 mu;l of the cell suspensions,and the second group,5 mice (10 eyes)with 10 mu;l．The transplanted RB was observed by inspection and ophthalmoscopy,and graded semi-quantitatively in vivo.Light and electrone microscopes were used for histopathological examination,ABC immunohistochemical methods for NSE and GFAP,and flow cytometric investigations for DNA index(DI) and s-phase fraction (SPF). Results All of the models of RB were successfully established by injecting the cell suspensions of human RB cell line into the mice vitreous cavities.The immunohistochemical reaction of the transplanted tumor cells to NSE was positive,and negative to GFAP．The DNA index was found to be more than 1.1,and the determination of SPF indicated the presence of proliferative ability of the transplanted RB cells. Conclusion The above findings reveal that the transplanted tumor cells were similar to those of the parent cells,hence the orthotopic heterotransplantation of RB via nude mice vitreous cavity injection is a superior method in establishing the animal model for the further experimental studies of gene therapies in vivo. (Chin J Ocul Fundus Dis,1998,14:144-148)
One of the major clinical characteristics of congenital stationary night blindness(CSNB)is dysfunction of rod photoreceptors of the retina.Rhodopsin,the photosensitive pigment of the rods,is essential for maintaining the normal function of rod photoreceptors.It is resonable to hypothesize that mutations or deletions of rhodopsin gene may be involved in the molecular defect of CSNB.To test this hypothesis,we are searching for rhodopsin gene mutations in patients with autosomal dominant CSNB.In this study,DNA fragments containing the coding sequences in exon 5 of rhodopsin gene were amplified by polymerase chain reaction(PCR)in 15 patients and 5 unaffected members from a large family with autosomal dominant CSNB.RFLP analysis of these DNA fragments demonstrated that in comparison with a control group of 12 normal persons,there is no obvious deletion in exon 5 of rhodopsin gene,and that mutations or deletions do not exist in codon 314,codon 347,and the third base of codon 313 as well as the first base of codon 348 of the rhodopsin gene in these CSNB patients,which suggest the molecular pathogenesis of autosomal dominant CSNB not involve mutations or deletions of these codons of the rhodopsin gene. （Chin J Ocul Fundus Dis,1993,9:66-69）
Eighteen SD rats with streptozotocin-induced diabetes were observed for the influence of magnesium in glycolytic pathway in their retinal tissue.The diabetic rats were divided into 3 groups:6 of them drank 0.5% Mgso4 solution every day,6 received intramuscular Mgso4 (0.05/kg)in half month interval,and the another 6 drank tape water every day.Six normal rats were employed as employed as nondiabetic control.The activity of the three crucial rate-limiting enzymes ralating to glycolytic pathway-hexokinase,phosphofructokinase and pyruvate kinase in retinal tissue of the rats was investigated after a period of 30days.The results revealed that the levels of the enzymes were significantly depressed in diabetic rats not taking magnesium,while the enzyme levels maintained nearly the same in diabetic rats taking magnesium,while the enzyme levels maintained nearly the same in diabetic rats taking magnesium as in the control group.This suggested that the glycolytic pathway in retinal tissue was disturbed in early stage of diabtes,and magnesium might play an important role in maintaining the normal metabolism of glucose. （Chin J Ocul Fundus Dis,1993,9:81-83）
Tweenty-one SD rats with streptozotocin-induced diabetes were investigated for the influence of magnesium in cAMP level in the retina of the diabetic rats. The diabetic rats were divided into 3 groups: group 1, drinking tap hehwater; group 2, drinking 0.5% MgSO4 solution and group 3, receiving intramuscular MgSO4(0.1g/kg) once a month. In addition, group 4, a controlgroup of normal nondiabetic rats fed with tap water. In aperiod of 5 months examination, the growth and health conditions of diabetic rats were found to be nearly normal in group 2, 3 and 4, manifested by gaining weight and soft, smooth hairs on the skin, in contrast with loss in weight, rough hairs and even dying of infection in 2 of the diabetic rats in group 1. furthermore, the level of cAMP content in retina was found significantly higher in the diabetic rats taking Mg++ in spite of the route of administration(group 2, 3), as well as in the control group(group 4) than that of the diabetic rats which were fed with tap water. These results demonstrated that Mg++ might play an important role in improving the metabolism of diabetic rats including the retinal tissue by influencing the level of cAMP content, which is necessary in nuclear acid metabolism, protein synthesis, proliferation and differentiation, and other intracellular metabolic processes. （Chin J Ocul Fundus Dis,1992,8:141-143）
The retina of SD rats was incubated in four types of the Eagle solution respectively. The results showed the cAMP level of retinas was the lowest in the hGnMg(high glucose with normal magnesium) solution but the cAMP level was significantly increased in the hGhMg(high glucose with high magnesium) and higher than that of normal control group. The cAMP level was the highest in the nGhMg(normal glucose with high magnesium). The results suggested that magnesium might play an important role in maintaining the normal metabolism of glucose of the retinal tissue. （Chin J Ocul Fundus Dis,1992,8:138-140）