Dynamic changes of periostin and collagen I in the sclera during progressive myopia in guinea pigs / Alterações dinâmicas de periostina e colágeno I na esclera durante miopia progressiva em cobaias

ABSTRACT Purpose: To investigate periostin and collagen I expression during a scleral remodeling in myopic eyes and to determine their role in collagen remodeling of the myopic sclera. Methods: Fifty one-week-old guinea pigs were divided into the control and form-deprivation myopia (FDM) groups. The eyes of animals in the form-deprivation myopia group were covered for 2, 4, and 8 weeks, or were covered for 4 weeks and then uncovered for 2 weeks. The diopters and axial lengths in the eyes in each group of guinea pigs were measured. Immunohistochemistry and reverse transcription polymerase chain reaction were used to detect the relative protein and mRNA expressions of periostin and collagen I in the scleral tissues of guinea pig. Results: Before masking, guinea pigs in the control and form-deprivation myopia groups were hypermetropic and did not differ significantly (p>0.05). Hypermetropic refraction in the control group gradually decreased. In guinea pigs from the form-deprivation myopia group, the refractive power gradually changed from +2.14 ± 0.33 D to -7.22 ± 0.51 D, and the axial length gradually changed from 5.92 ± 0.37 mm to 8.05 ± 0.34 mm from before until the end of masking. Before covering, no significant difference was observed in the relative collagen I and periostin mRNA and protein expression levels in the sclera of the guinea pig control and form-deprivation myopia groups (p>0.05). The relative collagen I and periostin protein and mRNA expression levels in the sclera of guinea pigs in the form-deprivation myopia group at 2, 4, and 8 weeks, and after covering the eyes for 4 weeks followed by uncovering for 2 weeks, were significantly lower than those in the control group (p<0.05). The collagen I and periostin mRNA expression levels were positively correlated with protein expression levels in the sclera of guinea pigs (protein: r=0.936, p<0.05; mRNA: r=0.909, p<0.05). Conclusions: Periostin was expressed in the myopic sclera of guinea pigs, and changes in periostin and collagen I expression were highly consistent. Periostin and collagen I may be involved in the regulation of scleral remodeling in myopia.

RESUMO Objetivo: Investigar a expressão da periostina e do colágeno I durante o remodelamento escleral em olhos míopes e determinar seu papel na remodelação do colágeno da esclera miópica. Métodos: Cinquenta cobaias com uma semana de idade foram divididas em grupo controle e miopia de privação de forma. Os olhos dos animais no grupo de miopia de privação de forma foram cobertos por 2, 4 e 8 semanas, ou foram cobertos por 4 semanas e depois descobertas por 2 semanas. As dioptrias e comprimentos axiais dos olhos em cada grupo de cobaias foram medidos. A imunohistoquímica e a reação em cadeia da polimerase com transcrição reversa foram utilizadas para detectar as expressões relativas de proteína e mRNA de periostina e colágeno I em tecidos esclerais das cobaias. Resultados: Antes do mascaramento, as cobaias nos grupos controle e miopia de privação de forma eram hipermetrópicas e não diferiam significativamente (p>0,05). A refração hipermetrópica no grupo controle diminuiu gradualmente. Nas cobaias do grupo de miopia de privação de forma, a potência de refração mudou gradualmente de +2,14 ± 0,33 D para -7,22 ± 0,51 D e o comprimento axial mudou gradualmente de 5,92 ± 0,37 mm para 8,05 ± 0,34 mm desde antes até o final do mascaramento. Antes do mascaramento, nenhuma diferença significativa foi observada nos níveis de expressão de mRNA e proteína de colágeno I e periostina na esclera dos grupos controle e miopia de privação de forma (p>0,05). Os níveis relativos de expressão de colágeno I e proteína periostina e mRNA na esclera de cobaias no grupo de miopia de privação de forma em 2, 4 e 8 semanas, e após cobertura dos olhos por 4 semanas seguido de descoberta por 2 semanas, foram significativamente menores que aqueles no grupo controle (p<0,05). Os níveis de expressão de mRNA, colágeno I e proteína periostina foram positivamente correlacionados com os níveis de expressão de proteína na esclera das cobaias (proteína: r=0,936, p<0,05; mRNA: r=0,909, p<0,05). Conclusões: A periostina foi expressa na esclerótica míope de cobaias e as alterações na expressão de periostina e colágeno I foram altamente consistentes. A periostina e o colágeno I podem estar envolvidos na regulação do remodelamento escleral na miopia.

Dynamic changes of periostin and collagen I in the sclera during progressive myopia in guinea pigs.

PURPOSE: To investigate periostin and collagen I expression during a scleral remodeling in myopic eyes and to determine their role in collagen remodeling of the myopic sclera. METHODS: Fifty one-week-old guinea pigs were divided into the control and form-deprivation myopia (FDM) groups. The eyes of animals in the form-deprivation myopia group were covered for 2, 4, and 8 weeks, or were covered for 4 weeks and then uncovered for 2 weeks. The diopters and axial lengths in the eyes in each group of guinea pigs were measured. Immunohistochemistry and reverse transcription polymerase chain reaction were used to detect the relative protein and mRNA expressions of periostin and collagen I in the scleral tissues of guinea pig. RESULTS: Before masking, guinea pigs in the control and form-deprivation myopia groups were hypermetropic and did not differ significantly (p>0.05). Hypermetropic refraction in the control group gradually decreased. In guinea pigs from the form-deprivation myopia group, the refractive power gradually changed from +2.14 ± 0.33 D to -7.22 ± 0.51 D, and the axial length gradually changed from 5.92 ± 0.37 mm to 8.05 ± 0.34 mm from before until the end of masking. Before covering, no significant difference was observed in the relative collagen I and periostin mRNA and protein expression levels in the sclera of the guinea pig control and form-deprivation myopia groups (p>0.05). The relative collagen I and periostin protein and mRNA expression levels in the sclera of guinea pigs in the form-deprivation myopia group at 2, 4, and 8 weeks, and after covering the eyes for 4 weeks followed by uncovering for 2 weeks, were significantly lower than those in the control group (p<0.05). The collagen I and periostin mRNA expression levels were positively correlated with protein expression levels in the sclera of guinea pigs (protein: r=0.936, p<0.05; mRNA: r=0.909, p<0.05). CONCLUSIONS: Periostin was expressed in the myopic sclera of guinea pigs, and changes in periostin and collagen I expression were highly consistent. Periostin and collagen I may be involved in the regulation of scleral remodeling in myopia.

Analysis of the genetic relationships from different genetic systems between the amylose content and the appearance quality of indica rice across environments

The genetic relationships between amylose content (AC) and appearance quality traits of indica rice (Oryza sativa L.) were investigated using conditional analysis and unconditional analysis in present experiment. The results from the unconditional analysis indicated that AC of rice positively correlated with brown rice (BR, i.e., dehulled but unmilled rice) length (BRL), width (BRW) and thickness (BRT), but was negatively correlated with the ratio of length to width (RLW). The conditional analysis showed that weight of brown rice (WBR) negatively affected the genetic relationships between AC and the appearance quality traits of rice except between AC and BRW, while the genetic relationships between AC and most appearance quality traits were negatively affected by protein content (PC). However, these influences were not apparent due to the impact of WBR or PC on the most covariance components of the different genetic systems between AC and the appearance quality traits. The conditional analysis showed that it was possible to improve AC while significantly reduce BRL and BRT under maintaining WBR. Furthermore, AC could be improved when BRL was reduced under maintaining PC, but BRW and BRT could be significantly increased.

Partitioning genetic effects due to embryo, cytoplasm and maternal parent for oil content in oilseed rape (Brassica napus L)

Analysis of genetic main effects and genotype x environment (GE) interaction effects on the oil content of oilseed rape (Brassica napus L.) was conducted by using a genetic model for the quantitative traits of seeds in diploid plants. The experiments were carried out over two years with 8 parents and a diallel mating design, which produced F1 and F2 generations. We found that the oil content of rape was simultaneously controlled by embryo genetic effect, cytoplasmic effects and maternal genetic effect as well as GE interaction effects, with the cytoplasmic and maternal effects playing the main role. The results indicate that selection of maternal plants for high oil content would be more efficient than selection based on single seeds. Since the GE interaction effects accounted for 73.69 percent of the total genetic effects and were more important than the genetic main effects it seems that selection might be influenced by environmental conditions. The estimate of narrow-sense heritability for oil content was 73.52 percent with the interaction heritability being larger than the general heritability, indicating that the early generations can be used for selection for high oil content. The prediction of genetic effects suggested that the parent cultivars Youcai 601 and Gaoyou 605 were better than the other cultivars for increasing oil content during the breeding of B. napus. The implications for the quantitative trait loci mapping of seed traits interfered by these three genetic systems is also discussed.