miRNA-27b-3p/TPX2 Axis Regulates Clear Cell Renal Cell Carcinoma Cell Proliferation, Invasion and Migration.

There is a wide variety of cancer cells that can be linked to the presence of TPX2. However, there is not a lot of evidence regarding its role in the development and maintenance of clear cell renal cell carcinoma (ccRCC). In our study, bioinformatics analysis was performed to obtain differentially expressed mRNAs and miR-NAs in ccRCC. Survival curves predicted correlation of TPX2 expression with patient survival. The upstream regulatory miRNA of TPX2 was predicted to be miRNA-27b-3p through database, and dual luciferase assay verified the targeted relationship. qRT-PCR and Western blot were employed for examination of TPX2 mRNA and protein expression in ccRCC cells. Proliferation, invasion, migration and cell cycle were detected by CCK-8, colony formation, wound healing, Transwell, and flow cytometry assays. The results showed that TPX2 showed very high expression in ccRCC, and patients with higher TPX2 expression had shorter relative survival. Low miRNA-27b-3p expression was found in ccRCC. Knockdown of TPX2 or forced expression of miRNA-27b-3p in ccRCC cells inhibited cell proliferation, migration, invasion, and arrested cell division in G0/G1 phase. Dual luciferase reporter presented that miRNA-27b-3p targeted TPX2 to inhibit its expression. Rescue experiments demonstrated that the miRNA-27b-3p/ TPX2 axis affected the biological functions of ccRCC cells. Concurrent overexpression of miRNA-27b-3p and TPX2 inhibited the facilitating effect of TPX2 on ccRCC cell growth. The results revealed novel regulatory mechanisms involved in ccRCC progression, hoping that it may spark an insight for later discovery about the new therapeutic targets for ccRCC.

Effect of Repeated Low-Level Red-Light Therapy for Myopia Control in Children: A Multicenter Randomized Controlled Trial.

PURPOSE: To assess the efficacy and safety of repeated low-level red-light (RLRL) therapy in myopia control in children. DESIGN: Multicenter, randomized, parallel-group, single-blind clinical trial. PARTICIPANTS: Two hundred sixty-four eligible children 8 to 13 years of age with myopia of cycloplegic spherical equivalent refraction (SER) of -1.00 to -5.00 diopters (D), astigmatism of 2.50 D or less, anisometropia of 1.50 D or less, and best-corrected visual acuity (BCVA) of 0.0 logarithm of the minimum angle of resolution or more were enrolled in July and August 2019. Follow-up was completed in September 2020. METHODS: Children were assigned randomly to the intervention group (RLRL treatment plus single-vision spectacle [SVS]) and the control group (SVS). The RLRL treatment was provided by a desktop light therapy device that emits red light of 650-nm wavelength at an illuminance level of approximately 1600 lux and a power of 0.29 mW for a 4-mm pupil (class I classification) and was administered at home under supervision of parents for 3 minutes per session, twice daily with a minimum interval of 4 hours, 5 days per week. MAIN OUTCOME MEASURES: The primary outcome and a key secondary outcome were changes in axial length and SER measured at baseline and the 1-, 3-, 6-, and 12-month follow-up visits. Participants who had at least 1 postrandomization follow-up visit were analyzed for treatment efficacy based on a longitudinal mixed model. RESULTS: Among 264 randomized participants, 246 children (93.2%) were included in the analysis (117 in the RLRL group and 129 in the SVS group). Adjusted 12-month axial elongation and SER progression were 0.13 mm (95% confidence interval [CI], 0.09-0.17mm) and -0.20 D (95% CI, -0.29 to -0.11D) for RLRL treatment and 0.38 mm (95% CI, 0.34-0.42 mm) and -0.79 D (95% CI, -0.88 to -0.69 D) for SVS treatment. The differences in axial elongation and SER progression were 0.26 mm (95% CI, 0.20-0.31 mm) and -0.59D (95% CI, -0.72 to -0.46 D) between the RLRL and SVS groups. No severe adverse events (sudden vision loss ≥2 lines or scotoma), functional visual loss indicated by BCVA, or structural damage seen on OCT scans were observed. CONCLUSIONS: Repeated low-level red-light therapy is a promising alternative treatment for myopia control in children with good user acceptability and no documented functional or structural damage.

[Accuracy of three common optometry methods in examination of refraction in juveniles].

OBJECTIVE: To compare the results of the three methods of Suresight handheld autorefractor, table-mounted autorefractor and retinoscopy in examination of juveniles patients with or without cycloplegia.
 METHODS: Firstly, 156 eyes of 78 juveniles (5 to 17 years old) were examined by using WelchAllyn Suresight handheld autorefractor and NIDEK ARK-510A table-mounted autorefractor with or without cycloplegia; secondly, retinoscopy was performed with cycloplegia.
 RESULTS: The spherical power measured by methods without cycloplegia were significantly greater than those measured with cycloplegia (P<0.05); without cycloplegia, there was no significant difference in spherical power, cylindrical power and cylindrical axis between Suresight handheld autorefractor and retinoscopy (P>0.05). These results were highly consistent, suggesting a tendency towards a short sight. However, the spherical power and cylindrical power measured by table-mounted autorefractor was significantly different (P<0.05); with cycloplegia, there was significant difference in spherical power between Suresight handheld autorefractor and retinoscopy (P<0.05).
 CONCLUSION: Cycloplegic retinoscopy is necessary for juvenile refraction examination. Under natural pupil situation, Suresight handheld autorefractor is better than table-mounted autorefractor, though both show a myopia tendency. Nevertheless, table-mounted autorefractor can be taken as a recommendation for the prescription of lens trial. As a strong reference for subjective optometry, retinoscopy should be the gold standard for measuring refractive errors.

Role of Sensory Pathway Injury in Central Post-Stroke Pain: A Narrative Review of Its Pathogenetic Mechanism.

Central post-stroke pain (CPSP) is a severe chronic neuropathic pain syndrome that is a direct result of cerebrovascular lesions affecting the central somatosensory system. The pathogenesis of this condition remains unclear owing to its extensive clinical manifestations. Nevertheless, clinical and animal experiments have allowed a comprehensive understanding of the mechanisms underlying CPSP occurrence, based on which different theoretical hypotheses have been proposed. We reviewed and collected the literature and on the mechanisms of CPSP by searching the English literature in PubMed and EMBASE databases for the period 2002-2022. Recent studies have reported that CPSP occurrence is mainly due to post-stroke nerve injury and microglial activation, with an inflammatory response leading to central sensitization and de-inhibition. In addition to the primary injury at the stroke site, peripheral nerves, spinal cord, and brain regions outside the stroke site are involved in the occurrence and development of CPSP. In the present study, we reviewed the mechanism of action of CPSP from both clinical studies and basic research based on its sensory pathway. Through this review, we hope to increase the understanding of the mechanism of CPSP.

Axial Shortening in Myopic Children after Repeated Low-Level Red-Light Therapy: Post Hoc Analysis of a Randomized Trial.

INTRODUCTION: Axial length (AL) elongation in myopia is considered irreversible. We aimed to systemically report unexpected AL shortening observed in a randomized clinical trial (RCT) after repeated low-level red-light (RLRL) therapy. METHODS: This is a post hoc analysis of a multicenter, single-masked RCT. Two hundred sixty-four myopic children aged 8-13 years allocated to RLRL treatment (intervention group) or a single vision spectacle (SVS, control group) were included. AL was measured using an IOL-master 500 at baseline, 1-, 3-, 6-, and 12-month follow-up visits. AL shortening was defined as AL reduction from baseline to follow-up visits at three cutoffs: > 0.05 mm, > 0.10 mm, and > 0.20 mm. Frequency of AL shortening at different cutoffs was calculated. Analysis was done with intent to treat (ITT). RESULTS: At 12-months follow up, frequency of AL shortening > 0.05 mm was 26/119 (21.85%) and 2/145 (1.38%) for the RLRL group versus the control group, respectively. The frequency was 18/119 (15.13%) versus 0/145 (0%) for AL shortening > 0.10 mm, and 7/119 (5.88%) versus 0/145 (0%), for AL shortening > 0.20 mm, respectively (p < 0.001). Mean AL shortening after 12 months (SD) was -0.156 (0.086) mm in the RLRL group and -0.06 mm in the control group. Age was significantly associated with AL shortening in the multivariable analysis. For the RLRL group that exhibited AL shortening (n = 56), choroidal thickness (ChT) thickening (0.056 mm) could only explain 28.3% of AL shortening (-0.20 mm). CONCLUSION: Nearly a quarter of children had > 0.05 mm AL shortening following 12 months of RLRL therapy, whereas AL shortening rarely occurred among controls. TRIAL REGISTRATION: ClinicalTrials.gov (NCT04073238).

[MK801 controls form-deprivation myopia by nitric oxide-cyclic GMP signaling pathway in guinea pig].

OBJECTIVE: To investigate the mechanism of myopia following intravitreous injection of MK801 (dizocipine maleate) intravitreous injected. METHODS: Three-week-old guinea pigs were divided into six groups: group A (control), group B (3 weeks form-deprivation in right eye), group C ( 3 weeks form-deprivation in right eye + saline), group D (3 weeks form-deprivation in right eye + MK801 1ng), group E (3 weeks form-deprivation in right eye + MK801 10 ng), group F (3 weeks form-deprivation in right eye + MK801 100 ng). The refraction and axial length of the eyes were measured. ncNOS was measured by hybridization in situ, and cyclic GMP (cGMP) concentrations by radioimmunochemistry. The correlation between MK801 concentration and diopter degree, axial length of the eyes, and levels of ncNOS or cyclic GMP were analyzed with linear correlation in the groups C-F. RESULTS: Diopter degree was decreased, axial eye length was shorted and levels of ncNOS and c-GMP were decreased in groups C, D, E and F dependent on the concentration of MK801. The diopter degree had positive correlation with MK801 concentration (r=0.702, P<0.05), while the axial eye length and the levels of ncNOS and cGMP were negatively correlated (r=-0.736, -0.637, -0.725, P<0.05) CONCLUSION: MK801 injected into the vitreous humor can restrain myopia by down-regulated the expression of the nitric oxide-cyclic GMP signaling pathway. The effect is concentration dependent.

The Effect of Endoscopy on Patients with Malignant Esophageal Cancer after Medical Treatment and Chemotherapy.

The esophagus is one of the most commonly used parts in a person's life, and its importance is self-evident. With the unhealthy food diet, people are more and more likely to suffer from esophageal cancer, and there is an urgent need for breakthroughs in the treatment of esophageal cancer. This article is aimed at studying the effects of medical treatment and chemotherapy for patients with malignant esophageal cancer. To this end, this article proposes a treatment method based on endoscopy and improves the image imaging of the endoscopy and the image quality of the image and the edge processing of the image. At the same time, this article designs an experiment to conduct statistical analysis of the situation during the treatment process. The experimental results in this article show that the improved treatment method has a 21% increase in success rate compared with the existing treatment method. And the optimized image quality has increased by 27%. It can very well help the attending doctor to improve the efficiency of treatment in the actual treatment process. Its most important contribution is that through the edge optimization and image enhancement processing technology, the success rate of endoscopic treatment has been better improved, and the treatment efficiency has also been improved.

[Expression of cyclic guanine monophosphate and the ultrastructure change in retina of guinea pig with form-deprivation myopia].

OBJECTIVE: To explore the expression of cyclic guanine monophosphate (cGMP) and the ultrastructure change in retina of guinea pig with form-deprivation myopia and the underlying mechanisms. METHODS: Three-weeks-old guinea pigs were distributed in 3 groups: an untreated group (Group I), a myopia 2-weeks group (Group II) and a myopia 3-weeks group (Group III), animals underwent monocular form-deprivation by facemask for 2 and 3 weeks. The right eyes were deprived and the left eyes were self-controlled. The refraction and axial length of the eyes was measured. Retina was observed by electron microscope. The expression of cGMP was detected by radioimmunochemistry. RESULTS: Deprived eyes in guinea pig showed significant development of myopia, the refraction and axial length was increased. The pathological changes in ultrastructure of retina were aggravated with the development of myopia. The expression of cGMP was significantly up-regulated in the deprived eyes compared with self-control eyes(P<0.05). CONCLUSION: Form-deprivation can up-regulate the expression of cyclic GMP, which might play an important role in the development of myopia.

Designed Artificial Transcription Factors Inhibit Hepatitis B Virus Transcription in HepG2.2.15 Cells.

Hepatitis B virus (HBV) causes serious health issues worldwide. Despite this, current treatment options for HBV have many drawbacks. Strategies to safely and specifically target HBV replication and survival at the transcriptional level within host cells are needed to combat current drawbacks in treatment. In this study, we designed a novel artificial transcription factor (ATF) with suppressive function to target and bind to the HBV core promoter, a component that plays a central role in the viral life cycle. ATF has attached specifically to the intended target site by using electrophoretic mobility shift assays (EMSA). We tested whether targeting this suppressive ATF had any effect on HBV gene expression by transfection factor, western blotting, and real-time PCR. In the presence of ATF, viral mRNA and DNA levels were significantly decreased within HepG2.2.15 cells compared to control cells. The HBV-derived protein expression of HBV-e antigen (HBeAg) and HBV-c antigen (HBcAg) was also significantly inhibited. These results show that ATF treatment targeting the HBV core protein promoter has an antiviral effect and inhibits HBV infection in host cells. These results further suggest that the design of new artificial transcription factors may be valuable antiviral therapies to treat HBV patients.

[High myopia and retinal ultrastructure of albino guinea-pigs].

OBJECTIVE: To explore the relationship between melanin synthesis and the congenital high myopia of albino guinea-pigs. METHODS: Twelve albino guinea-pigs and 12 pigmented guinea-pigs of 220~250 grams (aged 5~6 weeks) were chosen at random. The eyes were examined with retinoscopy, A-scan ultrasonography and vernier caliper. The retinal structures were examined with light and electronic microscope. RESULTS: The diopter was -19.17 D in albino guinea-pigs and +0.63 D in pigmented guinea-pigs on average. Compared with the pigmented guinea-pigs, the axial dimensions of the albino guinea-pigs were elongated. There was significant difference between the albino guinea-pigs and the pigmented guinea-pigs. The retinal thickness, pigment granules and membrane disc of the outer segment of the visual cells decreased in the albino guinea-pigs, and the membrane disc space became narrow. The normal retinal thickness, plenty of pigment granules , membrane disc and wide membrane disc space could be observed in the pigmented guinea-pigs. CONCLUSION: Albino guinea-pigs have high myopia, and pigmented guinea pigs have light hyperopia. There are structural differences in the retina between albino guinea-pigs and pigmented guinea-pigs. The abnormity of albino guinea-pigs provides optical foundation for its high myopia.

[Antisense c-fos oligonucleotides-induced myopia in guinea pigs].

OBJECTIVE: To characterize the antisense c-fos oligonucleotides that control the expression of immediate-early gene c-fos in retina in order to better understand the mechanism by which antisense c-fos oligonucleotides induced myopia. In this study the signal transduction in the pathway linking visual experience and the regulation of the eye's growth was investigated. METHODS: Thirty-one 3-week guinea pigs were assigned into 3 groups: antisense and sense c-fos oligonucleotides were intravitreally injected every 3 days to the eyes of the experimental guinea pigs at different concentrations; and saline vehicle to control guinea pigs in the same way. The refraction and axial length of the eyes were measured before and after the treatment, and the immediate-early gene c-fos expression in the retina was quantified by immunohistochemistry and RT-PCR. RESULTS: The moderate myopia was induced in high (1 nmol) and low (0.1 nmol) level of antisense c-fos oligonucleotide intravitreous injection (-5.425 D and -5.575 D, respectively) compared with the control ateral eyes. The refraction and axial length of the treated eyes increased, and the expression of immediate-early gene c-fos decreased significantly in the antisense c-fos oligonucleotides intravitreously injected eyes compared with the sense c-fos oligonucleotide intravitreously and saline vehicle injected eyes (P<0.01). The refraction and axial length were of no statistically significant differences among the sense c-fos oligonucleotides-treated eyes and saline-treated eyes and non-treated eyes (P>0.05). CONCLUSION: The obvious myopia can be induced by antisense c-fos oligonucleotides in guinea pigs; antisense c-fos oligonucleotides inhibit c-fos expression in the retina. Immediate-early gene c-fos may be a potential factor in the prevention of myopia and plays an important role in the signal transduction of the retina.

Basic fibroblast growth factor suppresses retinal neuronal apoptosis in form-deprivation myopia in chicks.

PURPOSE: Chorioretinal atrophy including retinal neuronal apoptosis occurred in chronic form-deprivation myopia induced by lid suture in chicks. We investigated whether exogenous basic fibroblast growth factor (bFGF) could simultaneously inhibit the excessive axial elongation and retinal neuronal loss in the myopic chick eyes. METHODS: Unilateral form deprivation was produced in neonatal male Hyline chicks by lid suture 24 hr after hatching. Ten microliters of solution containing 5 ng bFGF or PBS (vehicle) was injected into the vitreal chamber at 10 weeks of age, once every 3 days until week 12, when the animals were sacrificed. Ocular refraction and axial length were assessed by retinoscopy and calipers at the age of 12 weeks. Retinal apoptotic neurons and their caspase-3-like protease activity were analyzed by transmission electron microscopy, the terminal-deoxynucleotidyl transferase-mediated biotin-deoxyuridine triphosphate nick-end labeling (TUNEL) staining, and a colorimetric method using Ac-DEVD-pNA as a substrate. The number of TUNEL-positive cells was counted to analyize the survival activity of bFGF on retina. RESULTS: After 12 weeks of lid suture, the control eyes were either emmetropic or hyperopic, whereas the deprived eyes became myopic with axial length increased. TUNEL-positive nuclei, condensed nuclear chromatin, and apoptotic bodies were observed in posterior retinal outer nuclear layer (ONL) and inner nuclear layer (INL) in the myopic chick eyes. Activity of retinal caspase-3-like protease in these eyes was elevated. In addition to ameliorating myopic ocular growth, intravitreal bFGF therapy significantly reduced the number of retinal apoptotic neurons and downregulated caspase-3 activity. CONCLUSIONS: Exogenous bFGF effectively ameliorates the excessive axial elongation and retinal neuron apoptosis in chronic form-deprivation myopia in chicks. It is possible that bFGF will be a promising therapeutic agent for high human myopia.

[Apoptosis and c-myc protein expression in the retinal of form-deprivation myopia].

OBJECTIVE: To study the apoptosis of retina and the expression of c-myc protein in form-deprivation myopia. METHODS: Two-day-old chickens were sutured with right eyelid for 4, 8 and 12 weeks. After measurement of refracation, the eyeballs were observed by light microscope and taken photos. Retinal apoptotic cells were measured by TUNEL staining and flow cytometry. C-myc protein were examined by immunohistochemistry and flow cytometry. RESULTS: Lacquer crack lesions were found in sutured eyes at 12 weeks. Apoptotic cells were observed in retinal outer and inner nuclear layer of the sutured eyes at 12 weeks and obvious peak of apoptosis was observed in sutured eyes at 12 weeks. The expression of c-myc protein was significantly more than control eyes at 8 and 12 weeks. CONCLUSION: The apoptosis of retinal was present in form-deprivation myopia with the degeneration of retina. C-myc protein plays an important role in retinal apoptosis of myopia.

[The treatment of retinal apoptosis by Caspase 3 inhibitor Ac-DEVD-CHO in experimental myopia].

OBJECTIVE: To investigate the mechanism of retinal apoptosis in chick experimental myopia and the therapy of Caspase 3 inhibitor Ac-DEVD-CHO. METHODS: Chick myopia was induced by lid-suture. After Ac-DEVD-CHO had been injected into vitreous, myopia was confirmed by optometry. Subsequently, chick eyeballs removed were measured its extro-dimensions, and the change of fundus were observed. Retinal apoptotic cells were determined by electron microscopy, TUNEL technique and flow cytometry. Retinal Caspase 3 proteins and its activities were measured by immunohistochemistry, flow cytometry and a colorimetric method using Ac-DEVD-pNA as a substrate. RESULTS: Ocular diopters and extro-diameters in all sutured eyes remarkly increased in comparison with its control eyes at 12 weeks after lid-suture. Lacquer crack lesions were found in 41 of 90 sutured eyes (45.56%). Apoptotic cells were observed in retinal outer and inner nuclear layer of the sutured eyes, and its apoptotic rate was significantly more than in control eyes (P < 0.05). Moreover, the expression of retinal Caspase 3 proteins and its activities were increased. After Ac-DEVD-CHO was injected into vitreous, the decrease of retinal apoptotic rate, Caspase 3 proteins and its activities was found. The treated effect of Ac-DEVD-CHO was in a dose dependent manner. CONCLUSIONS: Caspase 3 plays an important role in retinal apoptosis of chick myopia. Ac-DEVD-CHO can effectively ameliorate retinal apoptosis by blocked the effect of Caspase 3.

[Dynamic changes of MMP-2 activity in the posterior sclera of chicks with form-deprivation myopia].

OBJECTIVE: To investigate the effect of form-deprivation on level of gelatinase in the posterior sclera in chicks. METHODS: Fifty 1-day-old chicks were monocularly deprived to establish the animal model of form-deprivation myopia (FDM). According to the duration of form-deprivation the experimental chicks were divided randomly and equivalently into 5 groups, which were deprived for 3, 7, 14, 21 and 30 days respectively. Meanwhile the other eyes of the deprived chicks were used as self-control groups and chicks of the same days were chosen randomly as the normal control groups for each FDM group. At each form-deprivation point the changes of degree of diopters and axial length of chicks in each group were recorded. The levels of gelatinase in posterior sclera of the experimental eyes were measured by gelatin enzymography. RESULTS: Compared with the normal and self-control groups, the levels of MMP-2 activity in FDM groups were much higher (P <0.01). With the increase of the time of monocular deprivation these changes became more significant and reached the top after 14 days' deprivation with an inter-group statistical difference (P <0.01). The dynamic changes of MMP-2 activity were the same as those of axial length and degree of diopters in each experimental groups. There was positive correlation between the MMP-2 activity and axial length (r = 0.989, P < 0.01). But there was a negative correlation between the MMP-2 activity and refractive degree. CONCLUSION: Increase of MMP-2 activity in the posterior sclera of chicks would be a direct key factor to trigger sclera ECM remodeling process in chick FDM.

[Dynamic expression of VIPR2 in form deprivation myopia].

OBJECTIVE: To investigate the dynamic expression and significance of vasoactive intestinal peptide receptor 2 (VIPR2) on retina-choroid-clera in high myopia. METHODS: Twenty-one yellow chicks of 1 day old were used in the research. The right eyes were the experimental group, covered continuously for 1 week, 2 weeks and 4 weeks respectively. The left eyes were not covered as the normal control group. Both groups were detected diopter degrees using retinoscopic refraction, determinated eyeball axis using ophthalmology ultra-A, and investigated VIPR2 expression on retina-choroid-sclera in both groups at three stages by SP immunohistochemical staining. RESULTS: The experimental eyes changed from hypermetropia at pre-experiment to high myopia during the experiment stages, and the diopter degrees were deeper and eyeball axis was longer along with the period of being covered. Both groups had strong expression of VIPR2 on photoreceptor-outer segment of the retina and choroids. The expression was down-regulated with the time in both groups. Compared with the control group, VIPR2 expression of the experimental group was significantly up-regulated (P < 0.05). CONCLUSION: Form deprivation could induce high myopia. The expression of VIPR2 existed on photoreceptor-outer segment of the retina and choroids. VIPR2 may play an important role on the formation and development of myopia.

Upregulated expression of N-methyl-D-aspartate receptor 1 and nitric oxide synthase during form-deprivation myopia in guinea pigs.

This study aimed to investigate the expression of N-methyl-D-aspartate receptor 1 (NMDAR1) and neuronal constitutive nitric oxide synthase (ncNOS) during form-deprivation myopia (FDM). FDM models were established in guinea pigs with facemasks. NMDAR1 expression in the retina was detected by immunohistochemistry and Western blot analysis. ncNOS mRNA expression was examined by in situ hybridization. cGMP content was measured by radioimmunoassay. In control group, NMDAR1 and ncNOS were expressed in binocular retinas, and there was no significant difference in NMDAR1 and ncNOS expression and cGMP content between the two eyes. However, NMDAR1 and ncNOS expression and cGMP content in the retina of FDM eyes were significantly higher than that of contralateral untreated eyes. Furthermore, ncNOS mRNA level and cGMP content was highly correlated. In conclusion, FDM upregulates the expression of NMDAR1 and ncNOS and increases cGMP content in the retina. NMDAR1/NO-cGMP pathway may contribute to abnormal visual signals during myopic progression.

[Matrix metalloproteinase-2 mRNA expression in the posterior sclera of chick form-deprivation myopia].

OBJECTIVE: To investigate the dynamic changes of matrix metalloproteinase-2 (MMP-2) mRNA expression in the posterior sclera of chick form-deprivation myopia (FDM) and its possible molecular mechanism. METHODS: Fifty white 1-day-old leghorn chicks were divided randomly and equally into 5 groups. The right eye of each chick was covered with a plastic goggle at 4, 7, 14, 21, and 30 postborn days respectively to induce FDM, and the left eye served as a self-control. Meanwhile, normal age-matched chicks were provided as negative control speciments for each group. Removing the goggle at every experiment point, refractive status and axial length were determined with streak retinoscopy (without cycloplegia) and A-scan ultra-sonography under topical anaesthesia, respectively. Both eyes were collected after the chicks were killed. The total RNA in the posterior sclera was extracted traditionally using TRIZOL reagent, and then the expression levels of MMP-2 messenger RNA were analyzed by one step reverse transcriptiontase-polymerase chain reaction. RESULTS: Compared with the normal and self-control groups, the expression levels of MMP-2 mRNA in the deprived eyes significantly increased (P < 0.001). With the delay of form-deprivation duration, MMP-2 mRNA expression levels increased significantly and especially reached a highest point at the 14th day of monocular deprivation. After that the level decreased slightly, but maintained at a high level. Although there was no significant difference between the normal control group and the self-control one (P > 0.05), MMP-2 mRNA expressed slightly higher in the self-controlled eyes. CONCLUSION: As a primary element to trigger early active sclera extracellular matrix remodeling process, MMP-2 gene is probably involved in the development of FDM by excessive degradation of extraceller matrix which can make sclera thinner and the eye axis longer.