| Lycium barbarum L.(L. barbarum) is a solanaceous defoliated shrubbery that has the history for over2500years as a traditional herbal medicine to nourish liver and kidney and brighten the eyes without any specific toxicity. This study we observe its possible therapeutic effects on common clinical experimental model:retinal ischemia, RCS rats as well as diabetic gastroparesis to provide new clinical strategies.PART I:Protective Effect of LBA on Retinal Ischemia:A preliminary studyObjective:To investigate protective effects of LBA on retinal ischemia model and its possible mechanism of apoptosis.Methonds:Thirty six male Wistar rats were devided into three groups, four for normal control, sixteen for normal soline control and sixteen for LBA treated group. Introcular pressure was increased to induce the retinal ischemia model. Before ischemia model was made, LBA1mg/kg was administrated p.o. in LBA group and at the same time normal soline (NS) was given in control group. Normal soline and LBA groups were classified into four subgroups:12h,24h,48h and72h after reperfusion respectively. Hematoxylin-eosin staining, TUNEL detection, as well as Fas/FasL immunohistochemical method were used to assess necrosis and apoptosis of photoreceptor cells.Results:(1) HE staining:In normal soline group,12h later after reperfusion we found INL become thinner and cell numbers become less.24h later, we found that GCL and INL cells mal-organized.48hours later, INL become much more thinner and cells obviously reduced.72hours latercINL become much more thinner. After reperfusion, INL thickness, INL cells as well as ganglion cells of LBA group become greater than that of NS control group.(2) TUNEL detectation:No positive cells were found in retinae of the normal rats, while it were found in INL and GCL of normal soline group twelve hours after reperfusion.24hours later, positive cells peaked and mostly located in INL, decreased after48hours. Positive cells in the LBA group was similar to NS control group, but cell numbers were much more less.(3) Fas/FasL staining:No Fas positive cells were found in retinae of the normal rats, while it were found in normal soline group twelve hours after reperfusion.24hours later, positive cells peaked and decreased after48hours. Positive cells in the LBA group was similar to NS control group, but cell numbers were much more less. FasL positive cells increased in normal soline group twelve hours after reperfusion.24hours later, positive cells peaked and decreased after48hours like Fas staining. Positive FasL cells in the LBA group was similar to NS control group, but cell numbers were much more less.Conclusion:(1) INL thickness, INL cells as well as ganglion cells of LBA group become greater than that of N.S control group after reperfusion, indicating that LBA has protective effect on retianl ischemia model.(2) Positive TUNEL cells in the LBA group less than that of control group, suggesting that apoptosis mechanism involved and could be inhibited by LBA administration.(3) Positive Fas/FasL cells in the LBA group was were much more less than normal soline group, indicating that LBA may exert its protective function by inhibiting its expression. Part Ⅱ:Neuroprotective effect of Lycium barbarum on retina of RCS rats:A preliminary studyObjective:Hereditary retinal dystrophy usually leads to blindness. Using Royal College of Surgeon (RCS) rats as the hereditary retinal dystrophy model, we investigated the possible neuroprotective effects of the aqueous extract of dried Lycium barbarum (LBA). Materials and Methods:Sixty postnatal RCS rats were selected and randomly divided into a control group (CG, thirty rats) and an experimental group (EG). Ten days after birth, EG rats were treated by1mg/kg LBA per day, and CG rats were normally fed. These rats were killed at postnatal day (P)25, P35and P50, and retinal tissue was prepared for analysis. Photoreceptor cells were assessed by hematoxylin and eosin (HE) staining, TUNEL detection and Caspase-2protein expression.Results:We found that in rats at P25, outer nuclear layer (ONL) of EG was thicker and more photoreceptor cells were survived. Meanwhile, TUNEL expression in EG obviously reduced compared with CG. The Caspase-2positive cells were found in the ganglion cell layer and inner nuclear layer in both CG and EG at25-50postnatal days, but expression in EG rats was significantly less than CG at P25.Conclusion:The results demonstrated that LBA might have a neuroprotective role on the retinal tissue of RCS rats at the early stage by protecting photoreceptors and inhibiting apoptosis involved Caspase-2protein. Part III:Effects of Lycium barbarum polysaccharide on blood glucose and gastric motility in diabetic ratsObjective:Gastroparesis is a common complication of Diabetes Mellitus (DM), bringing a serious threat to peoples’ health. Currently, none of drugs have been perfect. Lycium barbarum is the traditional Chinese medicine. In this study, we investigated the effects Lycium barbarum Polysaccharide (LBP) on diabetic gastroparesis (DGP) rats.Materials and Methods:LBP was administered orally at a dose of100,200and400mg/kg/day to streptozotocin induced diabetic rats for28days. The levels of glucose, insulin, insulin resistance index (IRI), ghrelin, ghrelin mRNA, gastric emptying rate, apoptosis index (AI) and Bcl-2/Bax ratio were analyzed. Results:LBP could significantly decrease blood glucose, insulin and IRI (P<0.05-0.001). The contents of ghrelin was significantly increased after administration of LBP with a dose dependent manner (P<0.05-0.001). On the contrary, the expression of ghrelin mRNA of gastric mucosa increased in DM rats (P<0.05), but decreased after LBP treatment (P<0.05). In addition, the gastric motility and gastric empty in LBP-treated DM rats were significantly accelerated (P<0.05) compared with the diabetic control rats. Bcl-2/Bax ratio was markedly increased in LBP-treated DM rats (P<0.05), but decreased for AI (P<0.05).Conclusion:LBP could ameliorate gastric motility in DM rats through declining blood glucose, increasing expression of ghrelin of gastric mucosa, and reducing cell apoptosis. |
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