Background Retinitis pigmentosa (RP)is a common hereditary blinding eye disease in ophthalmology.Current researches documented that RP may have the common pathophysiologic basis to Alzheimer disease and chronic neurodegenerative disease.Understanding this mechanism will offer a new therapeutic target for RP.Objective The purpose of the present study was to investigate the roles of cyclin-dependent kinase 5 (Cdk5)/P25 activation in the apoptosis of retinal neural cells of RCS rats.Methods Eighteen SPF RCS rats and 18 RCS-rdy+ rats were randomized into 17-,25-and 35-day groups respectively and 6 rats for each.The rats were sacrificed at corresponding time points and retinal hemogenete was prepared.Expressions of CdkS,P35,P25 and tau phosphorylation in the retinas were detected by Western blot,and the kinase activity of Cdk5/P25 was analyzed by quantitative colorimetric assay.Results The expressing level of P35 protein(A340) in the retinas of 17-day-old RCS rats was near that of 17-day-old RCS-rdy+ rats(t =0.52,P＞0.05).In 25-and 35-day-old RCS rats,the expressing levels of P35 protein were 2.20±0.48 and 1.23±0.14,which were higher than those of RCS-rdy+ rats(1.43±0.13 and 0.93±0.10),showing significant differences between them(t =3.78,4.28,P＜0.05).The expression of P25 was undetectable at postnatal 17 days in RCS rats and RCS-rdy+ rats,but it showed significantly higher in RCS rats(0.300±0.003 and 0.230±0.004) than that in RCS-rdy+ rats(0.040±0.004 and 0.070±0.004) at postnatal 25 days and 35 days(t=121.81,77.51,P＜0.01).No significant difference was found in the expression of Cdk5 in RCS rats and RCS-rdy+ rats at different ages (t =-0.60,0.19,1.62,P＞ 0.05).The kinase activity of Cdk5/P25 did not show significantly different between RCS and RCS-rdy+ rats at postnatal 17 days(t =0.19,P＞0.05),but significantly higher kinase activity of Cdk5/P25 was seen in RCS rats (0.0058 ±0.0005 and 0.0056±0.0004) than that in RCS-rdy+ rats(0.0038±0.0003 and 0.0032 ±0.0007) at postnatal 25 days and 35 days (t =8.07,5.97,P＜ 0.01).No expression of tau phosphorylation was detected in RCS rats at postnatal 17 days,but significantly higher tau phosphorylation level was seen in RCS rats at postnatal 25 days and 35 days(1.80±0.22 and 1.23±0.17),which were significant different in comparison with RCS-rdy+ rats at postnatal 25 days and 35 days(1.60 ±0.20 and 1.04 ±0.12)(t=4.71,3.17,P＜0.05).Conclusions The Cdk5/P25 kinase activity shows a consistent trend with theexpressions of P25 and tau phosphorylation in the RCS rats,indicating that the upregulation of P25 induces the enhance of enzyme activity of Cdk5,which phosphorylate its substrates to result in more apoptosis of retinal neural cells.

Background Retinitis pigmentosa (RP) is a monogenic inheritance and blinding disease of fundus oculi.There is not an effective therapeutic method now.Objective This work was to identify the mutations of RP1 gene in Chinese RP patients in Ningxia area and to explore the potential interactions in the pathogenesis of RP.Methods The periphery blood of 3-5 ml was collected from 110 individuals with RP(35 ADRP and 75SRP)and 100 normal controls in Ningxia area.Polymerase chain reaction (PCR) and direct DNA sequencing were used to screening the sequence alterations in the entire coding region and splice sites of RP1 gene.Multivariate analysis and two web-based programs( PolyPhen and SIFT) were used to analyze the results.Results Eleven mutation locus were detected in the exon 4 of RP1 gene including two novel sequence variants:p.Lys1152Lys without a higher mutation rate in comparison with normal control group(x2 =9.12 P＜0.01 ),but c.* 247A＞C with a higher mutation rate in comparison with normal control group(x2 =12.77,P＜0.01 ) and c.* 247A＞C mutation was thought to be correlated with RP( r=1.11,P＜0.05 ).The other ten mutation locus were reported as single nucleotide polymorphisms (SNP).The mutation rate of p.Gln1725Gln was found to be higher in the RP patients than the normal controls (x2 =42.09,P＜0.01 ),but no the significant correlation was seen between the pathogenesis of RP and mutation of p.Gln1725Gln(r=1.74,P＞0.05).p.Lys1152Lys mutation was found in only 1 patient.Three SNPs( p.Arg872His,Ala1670Thr,Ser1691Pro) were always occurred in the same 83 RP patient and the relevance ratio was higher than controls ( P＜0.01 ).The age of night blindness on patients with concurrent three mutations was (30.54± 13.68 ) years,and the best corrected visual acuity (BCVA) was 0.50 ± 0.38.The age of night blindness on patients without concurrent three mutations was(21.06± 16.24) years,and the BCVA was 0.40 ±0.33 and were higher than controls ( t =2.11,P ＜ 0.05 ).Conclusions In this study,the prevalence of RP1 mutations among the RP patients in Ningxia population was lower than other populations (＜ 1％ ).The alliance of SNPs (p.Arg872His、p.Ala1670Thr、p.Ser1691Pro) may play a protective role on RP patients and reduce the frequency of mutatiaon in RP1 gene.

AIM:To analyze the changes of retinal hemodynamics in patients with diabetic retinopathy (DR) by color Doppler ultrasonography.METHODS:Totally 96 patients (96 eyes) with diabetes mellitus (DM) treated in our hospital from June 2014 to May 2017 were selected and divided into A,B,C three groups.Group A consisted of 32 DM patients (32 eyes),Group B with 32 cases (32 eyes) of non-proliferative diabetic retinopathy (NPDR),Group C 32 cases (32 eyes)of proliferative diabetic retinopathy(PDR),and 30 healthy volunteers (30 eyes) were set as control group.All patients' the central retinal artery (CRA),posterior ciliary artery (PCA),ophthalmic artery (OA) hemodynamic changes were detected by color Doppler ultrasound.And the relation of HbA1c and FBG with diabetic lesion degree were studied.RESULTS:The hemodynamic indexes of CRA,PCA and OA in each group were statistically significant (P＜0.05).The difference of PSV of CRA,PCA and OA in Group A and control group was not statistically significant (P＞0.05).The PSV and EDV of CRA,PCA and OA in Group C were the lowest,and the RI was the highest,which had a significant difference between Group A and B (P＜0.05).HbA1c and FBG in each group showed statistical significance (P＜0.05).Course of disease in Group A and Group C only showed significantly different (P＜0.05).CONCLUSION:Color Doppler ultrasound monitoring changes of CRA,PCA,OA hemodynamics in diabetic patients can bring us more understand in retinal blood flow,and play a vital role in prevention and treatment of diabetic retinopathy.