| Objective:Immunosupression refers an age-related decline in immune functions with aging,which is also important tissues to study in biological aging.Thymus where cytogenesis and maturation of T cells takes place in is an important central immune organ and earlist and most strking during immunosenescence,so highly attention should be paid to how to delay senescence of thymus.Panax ginseng is applyed in clinic of Traditional Chinese Medicine for thousands of years,which possesses tonifyning Qi effectiveness.Modern medical research proved it can delaying senescence,regulating immune, confronting tumor,and protecting nerve,and so on.Our recent studies showed that Ginsenoside-Rglcan delay hematopoietic stem/progenitor cells senescence definitely and also induce lekemia K562 cells senescence.These results support the bisic theory of "two-way adjustment" or "strengthen body resistance and eliminating evil" of Panax ginseng.It has not been reported whether Ginsenoside-Rgl can defer senescence of immune organs.Firstly,aging model rats were made by injecting D-gal.Secondly,the effect of Ginsenoside Rgl on the structure and funtion of thymus of aging model rats were performed.We hope to provide novel idea and method to the delaying aging by the effective components of natual medicine based on the mechanism of Ginsenoside Rgl deferring immnosenescence.Methods:SD rats were randomly divided into (1) aging model group,(2)Rg1 aging model group (3) normal control group and (4)Rg1 control group,. Aging model group were injected with D-galactose (120mg/kg/d) for 42 days by subcutaneous way. Rg1 aging group were also given D-galactose with the same dose and time as aging model group, and from the 15th day on, rats were treated with Rgl (20 mg/kg/d) for 28 days by intraperitoneal way. Normal control group were received saline with the same volume for 42 days. Rgl control group were given saline with the same volume for 14 days, and received Rgl (20 mg/kg/d) for 28 days by intraperitoneal way. After 2 days of finishing injections, paraffin section were made to observe thymus microscopic structure and cortex/medulla ratio was measured. Senescence-accociated β-galactosidase (SA-β-Gal) stain was used to detect aging thymocytes. The proliferative capacity of thymocytes stimulated with Concanavalin A (Con A) was measured by CCK-8 and CFSE flow cytometry. The apoptosis and cell cycle of thymocytes was analyzed by flow cytometry(FCM).The content of TNF-α, GM-CSF, IL-2 and IL-6 were detected by ELISA.The expression of senescence-associated protein P53、P21、Rb were detected by Western blotting analysis.Results:(1) Comparing the aging model group aging group with the normal control group,the percentage of SA-β-Gal positive thymocytes, apoptosis ratet and G0/G1 ratio were obviously increased by D-gal.The proliferative capacity of thymocytes stimulated with Con A,thymus index, thymus cortex area proportion, the secretory capability of IL-2,TNF-a,GM-CSF,and IL-6 were obviously increased; the expression of P53、P21、Rb was also significantly up-regulated(2) Comparing the Rgl aging group with the aging model group,the percentage of SA-β-Gal positive thymocytes were obviously increased;the S ratio,the proliferative capacity of thymocytes stimulated with Con A,thymus index, thymus cortex area proportion and the secretory capability of cytokines were increased; the expression of aging-ralated protein was also significantly down-regulatedConclusions:(1) D-gal could induce senescent of SD rat and failing of thymus structure and function(2) Ginsenoside Rgl could antagonise the failing of thymus induced by D-gal, significantly improved the function of thymocyte.the mechanism invovled in may be Rg1 down-regulating aging-related protein. |
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