OBJECTIVE: To explore the underlying mechanism of inhibition by Jinkui Shenqi Pills (JKSQP) on glucocorticoid-enhanced axial length elongation in experimental lens-induced myopia (LIM) guinea pigs. METHODS: Sixty 2-week old male guinea pigs were randomly divided into 4 groups with 15 guinea pigs in each group, according to the random numbers generated by SPSS software: control, LIM, saline and JKSQP groups. The control group includes animals with no treatment, while the guinea pigs in the other 3 groups received lens-induced myopization on the right eyes throughout the experiment (for 8 weeks). The saline and JKSQP groups were given daily intraperitoneal injections of 10 mg/kg hydrocortisone for 2 consecutive weeks at the same time, and then orally administered either saline or JKSQP [13.5 g/(kg•d) for 6 consecutive weeks. Body weight, anal temperature and animal appearance were observed and recorded to evaluate the GC-associated symptoms. The ocular parameters, including refraction and axial length, were measured by streak retinoscopy and A-scan ultrasonography, respectively. The levels of plasma hormones associated with the hypothalamic-pituitary-adrenal axis (HPAA), including free triiodothyronine, free thyroxine, estradiol and testosterone, were measured by radioimmunoassay, and cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate were measured by enzyme-linked immunosorbent assay. In addition, the mRNA and protein expressions of retinal amphiregulin (AREG) was measured by quantitative real-time polymerase chain reaction and Western blotting, respectively. RESULTS: JKSQP effectively increased body weight and anal temperature, improved animal appearance and suppressed axial length elongation in glucocorticoid-enhanced myopic guinea pigs with normalization of 4 HPAA-associated plasma hormones (all P<0.05). The plasma level of cAMP was significantly increased, whereas the plasma level of cGMP and the mRNA and protein expressions of retinal AREG were decreased after treatment with JKSQP (all P<0.05). CONCLUSION JKSQP exhibited a significant inhibitory effect on axial length elongation with decreased expression of AREG in the retina, and normalized 4 HPAA-associated plasma hormones and the expression of cAMP and cGMP in GC-enhanced myopic guinea pigs.
Guinea Pigs ; Male ; Animals ; Glucocorticoids ; Hypothalamo-Hypophyseal System ; Pituitary-Adrenal System ; Myopia/metabolism* ; Body Weight ; RNA, Messenger ; Disease Models, Animal

PURPOSE: To compare oxidative stress status in the aqueous humor of highly myopic eyes and control eyes. METHODS: Aqueous humor samples were collected from 15 highly myopic eyes (high myopia group) and 23 cataractous eyes (control group) during cataract surgery. Central corneal thickness, corneal endothelial cell density, hexagonality of corneal endothelial cells, and cell area of corneal endothelial cells were measured using specular microscopy. Axial length was measured using ultrasound biometry. 8-Hydroxydeoxyguanosine (8-OHdG) and malondialdehyde levels were measured using enzyme-linked immunosorbent assay. RESULTS: 8-OHdG level was lower in the aqueous humor of myopic patients than in that of control group (p = 0.014) and was positively correlated with central corneal thickness and negatively correlated with axial length (r = 0.511, p = 0.02; r = -0.382, p < 0.001). There was no correlation between 8-OHdG level and corneal endothelial cell density, hexagonality, or cell area. Malondialdehyde level did not show any correlation with any parameters evaluated. CONCLUSIONS: 8-OHdG might be a sensitive biomarker for evaluating oxidative stress status in the eye. Oxidative stress level was lower in the aqueous humor of highly myopic eyes compared to that in control eyes, which indicates lower metabolic activity in these eyes.
Aged ; Aqueous Humor/*metabolism ; Deoxyguanosine/*analogs & derivatives/metabolism ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Male ; Malondialdehyde/*metabolism ; Middle Aged ; Myopia/*metabolism/physiopathology ; *Oxidative Stress ; Refraction, Ocular/*physiology ; Severity of Illness Index

BACKGROUNDMyopia is a common disorder and the incidence has increased yearly, but its pathogenesis remains unclear. The aim of this study was to investigate the possible role of hepatocyte growth factor (HGF) and its receptor c-Met in the development of lens-induced myopia in guinea pigs.

METHODSSixty one-week-old guinea pigs were chosen. The right eyes were treated with -10.0 diopters (D) lenses as the lens-induced myopia group; the left eyes remained untreated as the control group. Six weeks later, refractive status and axial length were determined by streak retinoscopy and A-scan ultrasonography, respectively. The guinea pigs were killed and both eyes collected. Morphological changes were observed by hematoxylin and eosin staining. The expression levels of HGF, c-Met, and matrix metalloproteinase 2 (MMP-2) mRNA and protein in the posterior sclera were analyzed by RT-PCR and Western blotting, respectively.

RESULTSThe lens-induced myopia group became myopic with a significant increase in axial length and a significant decrease in refraction. Compared with the control group, the posterior retina and sclera were thinner in the lens-induced myopia group. The expression levels of HGF and MMP-2 mRNA and protein and of phosphorylated c-Met protein were significantly higher in the posterior sclera of the lens-induced myopia group than in the control group (all P < 0.05). In the lens-induced myopia group, the expression level of MMP-2 in the posterior sclera positively correlated with the expression level of HGF (r = 0.902, P < 0.05) and phosphorylated c-Met (r = 0.885, P < 0.05).

CONCLUSIONHGF/c-Met might play a role in the development of lens-induced myopia in guinea pigs by upregulating the expression of MMP-2.

Animals ; Guinea Pigs ; Hepatocyte Growth Factor ; metabolism ; Myopia ; etiology ; metabolism ; Proto-Oncogene Proteins c-met ; metabolism

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.
Animals ; Cyclic GMP ; metabolism ; Dizocilpine Maleate ; administration & dosage ; pharmacology ; Down-Regulation ; Female ; Form Perception ; physiology ; Guinea Pigs ; Injections, Intraocular ; Male ; Myopia ; physiopathology ; Nitric Oxide Synthase Type I ; metabolism ; Sensory Deprivation ; physiology ; Signal Transduction ; drug effects ; Vitreous Body ; drug effects

The authors experienced two cases of hydrochlorothiazide (HCTZ)-induced acute-onset bilateral myopia and shallowing of the anterior chambers. Two middle-aged women taking HCTZ, a sulfa derivative, visited our clinic complaining of acute bilateral visual deterioration. Both had good visual acuity without corrective lenses before taking HCTZ. A complete ophthalmologic examination revealed bilateral myopic shift, intraocular pressure elevation, shallowing of the anterior chambers, choroidal effusions, radiating retinal folds, and conjunctival chemosis. Approximately one week after HCTZ discontinuance, all ocular changes disappeared completely. Physicians should be aware of the adverse ocular effects of HCTZ and should manage patients accordingly.
Acute Disease ; Adult ; Anterior Chamber/drug effects ; Choroid/drug effects/*metabolism ; Cilia/drug effects/*metabolism ; Diuretics/*adverse effects ; Exudates and Transudates/*metabolism ; Female ; Humans ; Hydrochlorothiazide/*adverse effects ; Intraocular Pressure/drug effects ; Middle Aged ; Myopia/*chemically induced

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.
Animals ; Cyclic GMP ; metabolism ; Disease Models, Animal ; Female ; Guinea Pigs ; Male ; Myopia ; etiology ; metabolism ; pathology ; Random Allocation ; Retina ; metabolism ; ultrastructure ; Sensory Deprivation ; Vision, Monocular ; physiology

OBJECTIVETo observe the expressions of the collagen , matrix metalloproteases-2 (MMP-2), and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) in the posterior sclera of newborn guinea pigs with negative lens-defocused myopia.

METHODSNewborn guinea pigs were monocularly defocused by -10D lens. After 4 weeks of defocus, the eyes were removed to provide posterior scleral samples for detection. Expression of collagen was detected by immunohistochemistry on frozen sections of guinea pig sclera, and the protein levels of MMP-2 and TIMP-2 were evaluated by Western blot.

RESULTSImmunohistochemical analysis indicated that the expressions of collagen and TIMP-2 were significantly lower and the expression of MMP-2 was significantly higher in the posterior sclera in the defocused eyes than in the contralateral eyes (all P < 0.01). However, all these indicators were not significantly different between the contralateral eyes and normal control eyes (all P > 0.05). In the defocused animals, the refraction of defocused eyes was positively correlated with the expression levels of collagen (r = 0.79, P < 0.01) and TIMP-2 (r = 0.74, P < 0.05) and was negatively correlated with the expression level of MMP-2 (r = -0.78, P < 0.01) in posterior sclera.

CONCLUSIONAlteration of extracellular matrix in the posterior sclera, probably participated by MMP-2, may exist during the development of defocus-induced myopia.

Animals ; Animals, Newborn ; Collagen Type I ; metabolism ; Disease Models, Animal ; Guinea Pigs ; Matrix Metalloproteinase 2 ; metabolism ; Myopia ; metabolism ; Sclera ; metabolism ; Tissue Inhibitor of Metalloproteinase-2 ; metabolism

OBJECTIVE: To observe the inhibitive effect of pirenzepine on form deprivation myopia in guinea pigs and to explore the mechanism of Smad3 signaling pathway and connective tissue growth factor (CTGF) in the inhibition of myopia by pirenzepine. METHODS: Forty 1-week-old guinea pigs of either sex were randomly divided into 4 groups: a control group (Group I), a form deprivation group (Group II), a pirenzepine ophthalmic solution group (Group III), and a sodium chloride ophthalmic solution group (Group IV). Translucent blinders were used in the right eyes of Group II, III and IV. The left eyes were not given any treatment as the normal control group. Covered eyes of Group III and IV were given 3% pirenzepine ophthalmic solution and 0.1% azone ophthalmic solution respectively twice every day. Six weeks later, refraction and axial length were measured at the end of the experiment, and immunohistochemistry and Western blot were used to analyze the expression levels of Smad3 and CTGF in the sclera of all 4 groups. RESULTS: There was no significant difference between Group III and I in relative refraction and changes of axial length (P>0.05). The difference of Group II and IV compared with Group I was statistically significant (P<0.05). The number of Smad3 and CTGF positive cells in the sclera between Group III and I was not significantly different (P>0.05), while the difference in Group II, IV and I was significant (P<0.05). Western blot showed that the expression levels of Smad3 and CTGF in Group II and IV were much lower than those in Group I (P<0.05), but not evident in Group III and I (P>0.05). CONCLUSION Pirenzepine ophthalmic solution can inhibit the development of form deprivation myopia. Pirenzepine may affect Smad3 signaling pathway in the sclera by inhibiting the development of form deprivation myopia.
Animals ; Connective Tissue Growth Factor ; metabolism ; Guinea Pigs ; Humans ; Muscarinic Antagonists ; administration & dosage ; Myopia ; prevention & control ; Pirenzepine ; administration & dosage ; Random Allocation ; Sensory Deprivation ; Signal Transduction ; drug effects ; Smad3 Protein ; metabolism

OBJECTIVE: To investigate the effect of regulation of VIPhybrid, an unselective antagonist of vasoactive intestinal peptide receptors (VIPR), on the formation and development of form deprivation myopia (FDM) in chick and the expression of protein and mRNA of VIP on the retina and choroids of in chicks. METHODS: Seventy-two 1-day-old yellow healthy leghorn chicks were assigned into 6 groups (12 in each group). Eyes in Group I were covered on the right as a blank control group. Eyes in GroupII were those eyes having been injected with 20 microL saline into vitreous cavity and then covered as a negative control group. Eyes in GroupIII,IV and V were injected with 20 microL VIPhybrid with low (3*10(-12) mol/L), middle (3*10(-10) mol/L) and high (3*10(-8) mol/L) dosage into vitreous cavity and then covered as experimental groups. The above groups had been continuously covered for 1 week. Eyes in Group VI were uncovered and uninjected as a normal control group. Diopter was detected using retinoscopic refraction. The eyeball axis was determined using ophthalmological ultra-A. The expression of protein and mRNA of VIP on retina-choroids-sclera were investigated by SP immunohistochemistry staining and RT-PCR. RESULTS: Form deprivation for 1 week induced high myopia eyes and elongated eyeball axis in GroupI and GroupII, and there was no difference between the 2 groups (P>0.05). The diopter and eyeball axis were significantly reduced in Group III, IV, and V as compared with Group I and II (P<0.01), but the diopter was higher and the eyeball axis was longer than those of Group VI. The diopter and eyeball axis had negative correlation with the concentration gradient of VIPhybrid. The expressions of protein and mRNA of VIP in Group III, IV, and V were down-regulated as compared with those of Group I and I I(P<0.01)and also down-regulated with the increase of concentration of VIPhybrid. CONCLUSION VIPhybrid can decrease the development of FDM in chicks, which may provide a new pathway for drug therapy of myopia in human beings.
Animals ; Animals, Newborn ; Chickens ; Myopia ; etiology ; metabolism ; RNA, Messenger ; biosynthesis ; genetics ; Receptors, Vasoactive Intestinal Peptide ; antagonists & inhibitors ; Recombinant Fusion Proteins ; pharmacology ; Retina ; metabolism ; Vasoactive Intestinal Peptide ; biosynthesis ; genetics

OBJECTIVETo investigate the expression of 5 muscarinic receptor subtypes in the scleral tissue of immature guinea pigs.

METHODSThe scleral tissue was collected from six 2-week-old pigmented guinea pigs to determine mRNA expressions of the muscarinic receptors with RT-PCR. Immunofluorescence was used to observe the protein expressions of the 5 muscarinic receptor subtypes.

RESULTSThe mRNAs of the 5 muscarinic receptor subtypes were all detected in the scleral tissue, and the mRNA expression was the highest for M1 subtype. Green fluorescence of M1 to M5 subtypes surrounding the fibroblast nuclei were found in the scleral matrix using laser confocal microscopy.

CONCLUSIONFive muscarinic receptor subtypes are present in the scleral tissues of immature guinea pigs, indicating the involvement of the muscarinic receptors in eye growth regulation.

Animals ; Female ; Gene Expression Regulation ; Guinea Pigs ; Immunohistochemistry ; Male ; Myopia ; metabolism ; pathology ; RNA, Messenger ; genetics ; metabolism ; Receptors, Muscarinic ; genetics ; metabolism ; Sclera ; cytology ; metabolism