| The main complication of DM in the eyes is diabetic retinopathy( DR) as a kind of irreversible blindness,it poses threat to visual function.The DR has not been fully elucidated so far because of the complex pathogenesis.With the deepen research in DR, people realize that DR is a neurovascular disease, nerve tissue damage may be earlier than the microvascular changes.The study found that apoptosis is closely involved in DM retinal nerve damage. The factors associated suicide(fas) and cysteine aspartic acid specific protease- 8(caspase- 8), as two promoting apoptosis factors, are the important targets of death receptor pathway in cell apoptosis.PRD is a compound Chinese herbal preparation that mainly consisting of bitter gourd and supplemented by salvia miltiorrhiza and ginseng, plus leeches, radix polygoni multiflori and radix pue rariae. The investigation is to explore the effect of PRD on fas and caspase-8 expression in the Otsuka Long-Evans Tokushima Fatty(OLETF) rat retina, which could provide theoretical basis for clinical application of PRD in the patients with DM.Objective:To explore PRD in OLETF rats fas and caspase-8 expression in the retina’s intervention, exploring PRD retinal nerve protective effect of DM rats.Methods:1 The male spontaneous T2 DM rats model OLETF rats and normal LETO rats were selected as the experimental objects, the criteria of the successful DM model is the peak plasma glucose >16.7 mmol/L and the load plasma glucose >11.1 mmol/L after 120 min.The above 24 OLETF rats with DM were randomly divided into DM model group and the PRD treatment group, and the 12 weeks old male LETO rats as the normal control group, each group 12 rats, with 12 weeks of male LETO rats as normal control group. The PRD treatment group rats were administered with PRD for 2 months and another two groups were given the equal distilled water.2 The HE staining to observe the morphology of rat retina structure change.3 The Td T mediated d UTP Nick end labeling method(TUNEL) to detect the rat retinal nerve cells apoptosis.4 SP immunohistochemical staining and western blot to analyze each rat retina protein expression of fas and caspase-8.Results:1 Pathological changes of rat retina’ organization in each groupNormal group: high magnification showed the retinas were complete in neat rows and cells were uniform, the membrane keeped integrity. Model group: compared with normal control group, retinal structures of the group were not very clear, retinal ganglion cells( RGCs) reduced, and with disordered arrangement, cavity change, nuclear pyknosis and karyolysis, and the internal limiting membrane were swelling, rough and ruptured. PRD group: compared with model group, retinal structures of the group were clear, arrangements of RGCs were mild disorder, number of RGCs was slightly decreased,internal limiting membrane roughness were less swelling and rough.2 Apoptosis of retinal cells were detected by TUNEL methodPositive performances of products were brown, granular, located in the nucleus, and could be seen in each group.Positive cells scattered in the inner nuclear layer and RGCs layer.Compared with normal control group,AI of retinal nerve cells in DM group was significantly increased(P<0.01). Compared with DM group,AI of retinal nerve cells in PRD treatment group was significantly decreased(P<0.01).3 fas protein expression in the rats’ retinaThe results of Immunohistochemical chromogenic showed that the positive result of fas is tan, fine particle, located in the cytoplasm.Immune positive cells distributed mainly parts of the kernel layer and RGCs. Group compared with normal control group, the DM rat retina fas positive expression was significantly increased(P<0.01);Compared with DM group, the PRD treatment group rats retinal fas positive expression significantly decreased(P < 0.01).4 caspase- 8 protein expression in the rats’ retinaImmunohistochemical color, according to the results of caspase- 8 positive result show the brown and fine granules, located in the cytoplasm. Positive cells mainly distributed in the kernel layer and RGCs layer.Compared with normal control group, caspase- 8 protein expression of rats’ retinal in DM group was significantly increased(P<0.01);Compared with DM group, caspase- 8 protein expression of rats’ retinal in PRD treatment group was significantly decreased(P<0.01).5 fas and caspase- 8 m RNA expression in the rats’ retinaCompared with normal group, caspase- 8 m RNA expression of rats’ retinal in DM group was significantly increased(P<0.01). Compared with model group rats, caspase- 8m RNA expression of rats’ retina in PRD treatment group was significantly decreased(P<0.01).Conclusion:1 PRD can inhibit the expression of fas, caspase- 8 in retina.2 PRD have an effect on protecting the diabetic retinal nerve tissue by reducing apoptosis of diabetic rats retinal nerve cells. |
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