| The world's elderly population is expanding rapidly,and we are now faced with the significant challenge of maintaining or improving physical activity,independence,and quality of life in the elderly.Age-related declines in muscle mass and strength,and often,frailty,known as sarcopenia,are an important antecedent of the onset of disability in older adulthood,because of its devastating effects in addition to an increased prevalence of aged people.The devastating health effects of sarcopenia are multiple: an increased falls risk,a decreased physical ability and quality of life and an independent increase of all-cause mortality.Although the ultimate remedy for sarcopenia yet has to be found,some interventions have proven their merit and might be of practical use in clinical practice,however,the underlying mechanisms of this pathologic ageing process are not fully understood,but different factors are believed to contribute such as inflammation,hormonal changes,inactivity and altered neuronal activity.Many older people have low to low-normal blood testosterone levels(?300 ng/d L).This has been associated with a loss of muscle mass and a decreased physical ability.There is an emerging role for testosterone and other anabolic steroids.In line with this,the desin of intranasal administration of testosterone propionate has been shown to observe amelioratory effects upon the hindlimb in aged rats.Objective: To investigate the amelioratory effects of intranasal administration of testosterone propionate(TP)on the physiologic function and morphological structure to hindlimb in aged rats.Methods: 30 male Wistar rats were used in this intranasal administration of TP study.30 rats were divided randomly into 3 groups consisting of 6Mon group,24 Mon group and 24Mon-TP group.For 24Mon-TP group rats,the rats received intranasal administration of TP(2mg/kg per day)at the age of 21 months.The supplement of TP was continued for 12 weeks.The rats in 24 Mon group were subjected to the same treatment using sesame oil as vehicle.The rats in 6Mon group has no any treatment.Tapered beam walking test were used to detect the behavior change of rats.HE stain were used to detect the morphological change of soleus muscle and extensor digitorum longus.Results:1 Tapered beam walking test: After the Tapered beam walking test,the footfaults were noted and then transformed to score by Equation 1 for standardization process(Zar,2009)to calculate the data.Compared with 6Mon rats,the left hindlimb score of 24Mon-TP rats and 24 Mon rats elevated obviously(P<0.05 or P<0.01),which showed the statistical significance and means the footfaults of aged rats increased markedly.Compared with 24 Mon rats,the score of 24Mon-TP rats reduced obviously(P<0.05),which showed the statistical significance and means the footfaults of aged rats decreased markedly but not restored to the level of 6Mon rats after intranasal administration of TP.Compared with 6Mon rats,the right hindlimb score of 24Mon-TP rats and 24 Mon rats elevated obviously(P<0.01),which showed the statistical significance and means the footfaults of aged rats increased markedly.Compared with 24 Mon rats,the score of 24Mon-TP rats reduced obviously(P<0.05),which showed the statistical significance and means the footfaults of aged rats decreased markedly but not restored to the level of 6Mon rats after intranasal administration of TP.2 HE stain: ? results of soleus muscle by HE stain showed:(1)Compared with 6Mon rats,the diameter of muscle cells on the cross session of 24 Mon rats shrinked obviously(P<0.05),which showed the statistical significance;compared with 24 Mon rats,the diameter of muscle cells on the cross session of 24Mon-TP rats enlarged obviously(P<0.01),which showed the statistical significance,it was even larger than that of 6Mon rats but there was no statistical significance.(2)Compared with 6Mon rats,the proportion of intercellular space of soleus muscle in unit area of 24Mon-TP rats and 24 Mon rats increased obviously(P<0.05 and P<0.01),which showed the statistical significance;compared with 24 Mon rats,the proportion of intercellular space of soleus muscle in unit area of 24Mon-TP rats redcued obviously(P<0.05),which showed the statistical significance but not restored to the level of 6Mon rats after intranasal administration of TP.? results of extensor digitorum longus by HE stain showed:(1)Compared with 6Mon rats,the diameter of muscle cells on the cross session of 24 Mon rats shrinked obviously(P<0.05,P<0.01),which showed the statistical significance;compared with 24 Mon rats,the diameter of muscle cells on the cross session of 24Mon-TP rats enlarged obviously(P<0.01),which showed the statistical significance but not restored to the level of 6Mon rats after intranasal administration of TP.(2)Compared with 6Mon rats,the proportion of intercellular space of extensor digitorum longus in unit area of 24Mon-TP rats and 24 Mon rats increased obviously(P<0.05 and P<0.01),which showed the statistical significance;compared with 24 Mon rats,the proportion of intercellular space of extensor digitorum longus in unit area of 24Mon-TP rats redcued obviously(P<0.05),which showed the statistical significance but not restored to the level of 6Mon rats after intranasal administration of TP.(3)Compared with 6Mon rats,the number of muscle fibers in muscle bundle on cross section of extensor digitorum longus of 24Mon-TP rats and 24 Mon rats decreased obviously(P<0.01),which showed the statistical significance;compared with 24 Mon rats,the number of muscle fibers in muscle bundle on cross section of extensor digitorum longus of 24Mon-TP rats increased obviously(P<0.01),which showed the statistical significance but not restored to the level of 6Mon rats after intranasal administration of TP.Conclusions: Intranasal administration of TP could reduce the number of footfault means improve the physical performance of aged rats,and reduce the proportion of intercellular space of musculi soleus and extensor digitorum longus in unit area means increase the proportion of muscle cell area and number of muscle fiber.Testosterone propionate have some protection effects on physiologic function and morphological structure of skeletal muscle in aged rats,which can provide certain experimental instruction for adjutant therapy to sarcopenia by intranasal administration of TP in clinic. |
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