| Part1:The relationship of aging and bone mineral densityObjective:To understand the effect of aging on the bone mineral density of rat by checking bone mineral density of femur, spine,pelvis,whole-body of different age groups of male Sprague-Dawley (SD) rats.Methods:Sprague-Dawley male Rat which was6-8weeks,6months,12months,24months old were be selected as subjects. There were10subjects in each group. We have detected bone mineral density of femur, spine, pelvis, whole-body of rats by dual-energy X-ray absorptiometry.Results:The bone mineral density of femur, spine, pelvis, whole-body in6-8weeks,6months,12months,24months old male rats groups are not the same, the difference was statistically significant(P=0.000). The bone mineral density of femur, spine, pelvis, whole-body of6-8weeks old groups lower than6months,12months,24months old groups, the difference was statistically significant(P=0.000). The bone mineral density of femur, spine, pelvis, whole-body of6months old groups lower than12months old groups, the difference was statistically significant(P=0.000). The bone mineral density of femur, spine, pelvis, whole-body of24months old groups lower than6months,12months old groups, the difference was statistically significant(P=0.000).Conclusion:The bone mineral density of femur, spine, pelvis, whole-body of rats increasing with aging, it was the lowest at6-8weeks of age, by6months old, there was a increase and when12months old increased to a maximum then decrease at24months of age, indicating that Sprague-Dawley male rats similar to humans, the bone mineral density reached the highest at youth and appear decrease when elder, experienced bone loss with aging.Part2:The relationship of regulatory T cells and senile osteoporosisObjective: To understand the effect of regulatory T cells on senile osteoporosis by measuring the percentage of regulatory T cells accounted for CD4+T cells in different age groups of male SD rats.Methods:We drew off blood from the heart of rate, used CD25/forkhead box P3double-positive to describe regulatory T cells and then measured the percentage of regulatory T cells accounted for CD4+T cells by flow cytometry.Results:1、The percentage of regulatory T cells accounted for CD4+T cells in6-8weeks,6months,12months,24months old male rats groups are not the same, the difference was statistically significant(P=0.000). The percentage of regulatory T cells accounted for CD4+T cells of6-8weeks old groups lower than6months,12months,24months old groups, the difference was statistically significant(P=0.000). The percentage of regulatory T cells accounted for CD4+T cells of6months old groups lower than12months,24months old groups, the difference was statistically significant(P<0.05). The percentage of regulatory T cells accounted for CD4+T cells of24months old groups lower than12months, but there was no significant difference(P>0.05).2、we found a positively correlated between the percentage of regulatory T cells accounted for CD4+T cells and bone mineral density of femur, spine, pelvis, whole-body.Conclusion:1、The percentage of regulatory T cells accounted for CD4+T cells in four groups are not the same, it was the lowest at6-8weeks of age, by6months there was a increase and when12months increased to a maximum then decrease at24months of age, indicating that the percentage of regulatory T cells accounted for CD4+T cells in different age groups were significantly different.2、The positively correlated between the percentage of regulatory T cells accounted for CD4+T cells and bone mineral density of femur, spine, pelvis, whole-body, indicating that because of the bone resorption reducing with the percentage of regulatory T cells increasing, the values of bone mineral density raising, when the percentage of regulatory T cells decreasing, the values of bone mineral density declining. In view of the number of Treg regulatory T cells declining with aging, we hypothesized that exogenous injection of regulatory T cells may inhibit the bone resorption by osteoclast, which may become the new direction of senile osteoporosis treatment.Part3:The effect of regulatory T cells on OPG-RANK-RANKL pathway of senile osteoporosis.Objective:To further explore the effect of regulatory T cells on OPG-RANK-RANKL pathway of senile osteoporosis by measuring the serum levels of RANKL and OPG in different age groups of male SD rats.Methods:Blood were drew off from the heart of rats, we have measured the serum levels of RANKL and OPG by enzyme-linked immunosorbent assay.Results:1、The serum levels of RANKL in6-8weeks,6months,12months,24months old male rats groups are not the same, the difference was statistically significant(P=0.00).6-8weeks old groups higher than6months,12months,24months old groups, the difference was statistically significant(P<0.05).6months old groups higher than12months old groups, the difference was statistically significant(P=0.008).6months old groups compare to12months old groups, there was no significant difference(P=0.928).12months old groups lower than24months old groups, the difference was statistically significant(P=0.010). 2、The serum levels of OPG in6-8weeks,6months,12months,24months old male rats groups are not the same, the difference was statistically significant(P=0.00).6-8weeks old groups higher than6months, but there was no significant difference(P=0.082).6-8weeks old groups higher than12months,24months old groups, the difference was statistically significant(P=0.000).6months old groups higher than12months,24months old groups, the difference was statistically significant(P<0.05).12months old groups higher than24months old groups, the difference was statistically significant(P=0,018).3、we found a negative correlation between the serum levels of RANKL and bone mineral density of femur, spine, pelvis, whole-body and the percentage of regulatory T cells accounted for CD4+T cells, the difference was statistically significant(P<0.01).4、we found a negative correlation between the serum levels of OPG and bone mineral density of femur, spine, whole-body, the difference was statistically significant(P<0.05).There was no correlation between the serum levels of OPG and bone mineral density of pelvis.Conclusion:1、The serum levels of RANKL in6-8weeks,6months,12months, groups decreasing with aging,24months groups increased slightly, indicating that the serum levels of RANKL in different age groups were significantly different.2、The serum levels of OPG in6-8weeks,6months,12months,24months groups decreasing with aging, indicating that the serum levels of OPG in different age groups were significantly different.3、The negative correlated between the serum levels of RANKL and bone mineral density of femur, spine, pelvis, whole-body, indicating that from6-8weeks to12months old with the serum levels of RANKL decreasing, there was a gradually raising of the bone mineral density, by24months old, the serum levels of RANKL appear increase, while bone mineral density appear decline. The negative correlated between the serum levels of RANKL and the percentage of regulatory T cells accounted for CD4+T cells, indicating that because of from6-8weeks to12months old the serum levels of RANKL gradually decreasing with the percentage of regulatory T cells gradually increasing, the formation of Osteoclasts reducing, the values of bone mineral density gradually raising; by24months old, the serum levels of RANKL increasing with the percentage of regulatory T cells decreasing, the inhibition of osteoclasts differentiation reducing, the values of bone mineral density appear declining, we speculate that regulatory T cells inhibit the differentiation of osteochasts may though suppress the expression of RANKL, thereby reduced bone resorption.4-. The negative correlated between the serum levels of OPG and bone mineral density of femur, spine, whole-body, indicating that owing to the serum levels of OPG decreasing with aging, the values of bone mineral density gradually raising. There was no correlation between the serum levels of OPG and bone mineral density of pelvis, indicating that OPG had no significant effect on the bone mineral density of pelvic. |
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