[Analysis on the effect of secondary mutations on Leber's hereditary optic neuropathy].

OBJECTIVE: To investigate the effect of secondary mutations on Leber's hereditary optic neuropathy (LHON). METHODS: Three primary and 24 secondary mutations were identified in 4 Chinese families which included male offspring. RESULTS: All of the four pedigrees carried classic LHON mutations at nucleotide (nt) 11778, and did not carry any point of 24 secondary mutations. Nevertheless many polymorphic points were found in the nearby fragments of these pedigrees, such as 5178, 5108, 3705, 3721, 13734, etc. CONCLUSION: Male offspring sequences should be analyzed in pedigrees with LHON to avoid the influence of familial inheritance characteristic which mitochondrial DNA polymorphism carried. Existence of the "repair genes" may affect the development of LHON.

Role of Caspase-3 in acute light damage to retina of rats.

OBJECTIVE: To investigate the role of Caspase-3 in retinal damage caused by light exposure in rats. METHODS: Light injury to retina was induced by persistent exposure to illumination (intensity: 30 000 +/- 50 lux) of operating microscope for 30 minutes in the right eyes of Sprague-Dawley rats. The pathological changes of retina were observed under optical and electron microscopies at different time points, which were 6 hours, 1, 3, 7, and 15 days after the light exposure. Apoptosis of retinal cells was analyzed by flow cytometry. The activity of Caspase-3 was evaluated by using the Caspase-3 assay kit. At the same time, the expression of Caspase-3 protease was determined with Western blot analysis. RESULTS: The examination results of optical and transmission electron microscopes showed that edema of inner and outer segments of the retina, especially the chondriosome inside the inner segment, became obvious 6 hours after the light exposure. The change was deteriorated along with the increasing time. The structures of the discoidal valve dissociated in the outer segment simultaneously. Disorderly arranged nuclei, karyopycnosis, and thinning in the outer nuclear layer were observed. The retinal pigment epithelium almost disappeared during the later stage. The staining results of Annexin-V combined with PI demonstrated that the proportion of apoptotic cells increased with time. The proportion between 7th day (82.7%) and 15th day (80.4%), however, showed no significant difference. Caspase-3 became remarkably active with the lapse of time, which increased from 0.02 at 6th hour to the peak of 9.8 at 7th day before it started to descend. The Western blot detected a expression of the active form of Caspase-3 at 7th day and 15th day. CONCLUSION: Apoptosis of photoreceptor cells is markedly involved in the light damage and Caspase-3 protease may play an important role in the apoptotic process of the retina after light exposure in rats.

[Changes of NF-kappaB/I kappa B alpha in N-methyl-N-nitrosourea-induced retinal damage in rats].

OBJECTIVE: To observe the changes of nuclear factor-kappa B (NF-kappaB) in the course of N-methyl-N-nitrosourea (MNU)-induced apoptosis of rat retinal photoreceptor cells and investigate the mechanism of MNU-induced retinal damage. METHODS: A single intraperitoneal injection of 60 mg/kg MNU was given to 50-day-old female rats, which were sacrificed at different intervals after MNU treatment. The retinal damage was examined with optical microscopy and photoreceptor cell apoptosis detected by TUNEL assay. Western blotting was performed to analyze the changes in NF-kappaB. RESULTS: Pyknosis of the photoreceptor cell nuclei and disorientation of the outer segment of the photoreceptor layer was observed 24 h after MNU treatment, and the outer nuclear layer and photoreceptor layer were almost completely lost on day 7. Photoreceptor cell apoptosis peaked at 24 h, and in the apoptotic cascade, NF-kappaB p65 protein was only detected 12 and 24 h after MNU treatment, whereas the amount of I kappa B alpha, in contrast, markedly increased in the cytoplasm as well as in the nuclei. CONCLUSION: MNU-induced retinal damage might be mediated through the signaling pathway of NF-kappaB/I kappa B alpha.

[Citation characterization of the ophthalmological journals in Chinese in 2001].

OBJECTIVE: To investigate the utilization and the requirement of literatures by the researchers through analyzing and valuing citation of the ophthalmological journals in Chinese. METHODS: There were 13 journals, of which five were core journals, to publish the results of primary study in ophthalmology in 2001. The citation amount and type, language category, self-citing rate of 13 journals were calculated. Meanwhile, the time distribution of citation, the Price index, the half-citing life and the cited situation of 5 core ophthalmological journals were investigated. RESULTS: In 2001, total amount of citations of 13 journals were 16,429. The mean citations per article were 5.13, and the mean citation rate 77.42%, self-citing rate 23.49%, other-citing rate 76.51%. The major language of citation was English (59.17%), and the major citation was from journals (89.25%). In 5 core ophthalmological journals, the time distribution of foreign language and Chinese references ranked at highest was the fourth and third year, respectively, after they were published. The total Price index of citations was 35.22%, the half-citing life of the Chinese and English references was 5.12 and 7.52 years, respectively. CONCLUSIONS: The main citations of 13 ophthalmological journals came from the English journals. There was a short half-citing life for Chinese literatures. Cited-papers in Chinese were mainly from five core ophthalmological journals.

[Protective effects of ligustrazine against photoreceptor cell injury induced by N-methyl-N-nitrosourea and its mechanism].

AIM: To study the protective effect of ligustrazine against photoreceptor cell injury induced by N-methyl-N-nitrosourea (MNU) in Sprague-Dawley (SD) rats. METHODS: Ligustrazine injections of different doses were injected intraperitoneally into 47-day female SD rats once a day and a single intraperitoneal injection of MNU 60 mg x kg(-1) was given to 50-day rats. At different intervals after MNU treatment,the animals were sacrificed. The apoptotic index of photoreceptor cells was calculated by TUNEL labeling at 24 h following MNU treatment; peripheral retinal damage was evaluated based on retinal thickness at the d 7 after MNU treatment, and the expression of c-jun and c-fos genes was detected by RT-PCR technique. RESULTS: Ligustrazine injection could remarkably increase total thickness of peripheral retina and decrease apoptotic index of photoreceptor cells induced by MNU in a dose-dependent manner. Compared with MNU-treated rats, the gene expression of c-jun and c-fos was time-dependently down-regulated in ligustrazine-treated group. CONCLUSION: Ligustrazine injection partially protects against MNU-induced retinal damage by down-modulating the expression of c-jun and c-fos genes to inhibit apoptosis of photoreceptor cells.

N-methyl-N-nitrosourea-induced apoptosis of photoreceptor cells in Sprague-Dawley rats via nuclear factor-kappaB.

BACKGROUND: Previous studies have showed that photooxidative stress can lead to down-modulation of nuclear factor-kappa B (NF-kappaB) activity causing apoptosis of cultured photoreceptor cells. This study aimed at investigating whether NF-kappaB was involved in photoreceptor cells apoptosis induced by N-methyl-N-nitrosourea (MNU) in rats. METHODS: A single intraperitoneal injection of 60 mg/kg MNU was given to 50-day-old female rats. At different intervals after MNU treatment, the animals were sacrificed. Retinal damage was examined by a light microscope. The apoptotic index of the photoreceptor cells was detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL). NF-kappaB was analysed by Western blot and Transcriptin Factor Assay Kits. RESULTS: The pyknosis of the photoreceptor nuclei and the disorientation of the outer segment of the photoreceptor layer was seen after MNU treatment for 24 hours. The outer nuclear layer and photoreceptor layer were almost completely lost at 7 days. Photoreceptor cells apoptosis reached the peaked value at 24 hours. In apoptotic cascade, the protein levels of NF-kappaB p65 were only detected after MNU treatment for 12 and 24 hours in the nucleus. Conversely, the amounts of IkappaBalpha were markedly increased in the cytoplasm as well as in the nucleus. The activity of NF-kappaB p65 in the nucleus was down-modulated in the end. CONCLUSIONS: MNU-induced photoreceptor cell destruction was attributed to the apoptotic process by down-regulating the activation of NF-kappaB p65.

Tetramethylpyrazine protected photoreceptor cells of rats by modulating nuclear translocation of NF-kappaB.

AIM: To evaluate the effect of tetramethylpyrazine (TMP) injection on retinal damage induced by N-methyl-N-nitrosourea (MNU) in rats and on nuclear factor-kappa B (NF-kappaB) family members. METHODS: Female Sprague-Dawley (SD) rats were randomly divided into groups: (i), control group; (ii), model group; and (iii), TMP-injection groups, in which the rats were subdivided into 40 mg/kg, 80 mg/kg and 160 mg/kg groups. Drugs were injected ip into 47-day-old SD rats once a day. At 50 days of age, all rats in the model group and drug groups also received a single ip injection of 60 mg/kg MNU. Rats in group 1 received ip injection of physiological saline. All rats were killed at different times after MNU or physiological saline treatment. The apoptotic index of photoreceptor cells was calculated by TUNEL labeling; retinal damage was evaluated based on retinal thickness and the expression of NF-kappaB family members was detected by Western blot. RESULTS: TMP injections, in a dose-dependent manner, suppressed photoreceptor cell apoptosis and decreased its loss in the peripheral retina. As compared with the MNU-treated group, TMP injection at a dose of 160 mg/kg also time-dependently upregulated the NF-kappaB/p65 protein level in the nucleus and downregulated the IkappaBalpha protein level in the cytoplasm. However, no protective effect of TMP injection on MNU-induced central retinal damage was found. CONCLUSION: TMP injection partially protects against MNU-induced retinal damage by upregulating the nuclear translocation of p65 to inhibit photoreceptor cells apoptosis.

[Effect of argon laser photocoagulation on diabetic retinopathy].

OBJECTIVE: To observe the clinical effect of argon laser photocoagulation on diabetic retinopathy (DR) in different stages. METHODS: A total of 263 eyes in 170 patients with DR in different stages were photocoagulated using argon laser machine 2000. Thirty eyes in non-proliferative stage received focal photocoagulation, 156 pre-proliferative eyes received subtotal panretina photocoagulation, and 77 proliferative eyes were treated with panretinal photocoagulation. Additional focal or grid treatment was given for the eyes with localized or diffused macular edema. The visual acuity, eye fundus examination and retinal fluorescein angiography were carried out 3 months after the treatment and the results compared with the preoperative findings. RESULTS: Improvement of visual acuity by at least one row on the visual chart was achieved in 92 eyes (35%), 144 eyes (55%) exhibited no changes, and 27 eyes (10%) deteriorated. Microaneurysm, retinal edema, exudates and fluorescence leakage were reduced in 89% of the eyes, with the rest eyes requiring additional treatment in the non-proliferative and pre-proliferative stages. For the retina in proliferative stage, neovascularization on the disc resolved completely in 67% eyes, whereas partially in 33% eyes which needed additional photocoagulation. The eyes with partial and complete resolution of macular edema accounted for 91% of the total eyes. Postoperative pre-retinal hemorrhage and vitreous hemorrhage occurred at the rates of 8% and 1%, respectively. CONCLUSION: Argon laser therapy is effective for the eyes with DR in different stages, but produces better efficacy in non- and pre-proliferative stages than in proliferative stage. Follow-up and additional photocoagulation are necessary for the eyes in proliferative stage to ensure better outcome.

[Clinical study of argon laser photocoagulation for central serous chorioretinopathy].

OBJECTIVE: To evaluate the clinical effect of argon laser photocoagulation for central serous chorioretinopthy. METHODS: This study included 102 consecutive cases of central serous chorioretinopathy (102 eyes) with fluorescein dye leakage located 500 microm away from the central fovea of the macula lutea as defined by fundus fluorescein angiography (FFA). Argon laser photocoagulation of the leakage spots was performed once (98 eyes) or twice (4 eyes) with the spot diameter for exposure ranging from 100 to 200 microm and exposure time of 0.2 s that delivered energy of 80 to 150 mW. RESULTS: The visual acuity was improved in 95 cases by one row on the standard vision chart within 2 or 3 d after the laser treatment, while in the other 7 cases, the visual acuity remained unchanged. The symptoms of micropsia, metamorphopsia and blurred vision disappeared in 87 cases. Serous detachment of the sensory retina and the fovea light reflex recovered in 80 cases within two weeks after the treatment and no fovea injuries due to photocoagulation were recorded. During the follow-up lasting for 6 to 12 months no recurrence or long-term complications in relation with photocoagulation treatment were observed in these cases. CONCLUSION: Argon laser photocoagulation is effective for central serous choiroretinopathy, and strict control of the photocoagulation conditions is crucial for preventing complications in relation to laser coagulation.