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Objective To investigate the morphological alteration and the protein expression of caspase -3 in long -term denervated posterior cricoarytenoid muscles (PCAMs)in order to find the appropriate time point of rein‐neration in long -term denervated PCAMs .Methods A total of 45 patients with vocal paralysis were recruited and devided into 3 groups ,the 3~6 months denervation group ,the 6~12 months denervation group ,the 1~2 year denervation group .12 adults served as control group .The morphological alteration was evaluated using HE staining and the change in expression of caspase -3 ,an apoptosis related factor ,were observed using immunehistochemistry stain and western blot .Results With elongation of denervation time ,there were increased denaturation in the mus‐cle fibers .The nucleus moved inside and some of them concentrated .Caspase-3 showed weak staining in innerva‐ted ,however ,by 3-6 months of muscle denervation there was a significant accumulation of caspase -3 protein in myofibers ,6~12 months and 1~2 years of denervation ,expression of caspase -3 protein in myofibers was de‐creased significantly .In western blot ,the change in protein expression of caspase -3 was observed an 21-fold (P< 0 .01) increase from 3~6 months denervated muscles to innervated muscles ,11-fold (P< 0 .01) increase from 6~12 months denervated muscles to innervated muscles ,3~fold (P< 0 .01) increase from 1~2 year denervated muscles to innervated muscles .Conclusion The morphological alterations and changes in expression of caspase -3 indicated there was a high amplitude of apoptosis in denervated posterior cricoarytenoid muscles within 1 year .
ABSTRACT
Objective: To investigate the change in myogenin expression at different time in long-term denervated human posterior cricoarytenoid muscles (PCAMs), so as to provide a theoretical basis for timing of reinnervation. Methods: Thirty-eight specimens of denervated human PCAMs were divided into 4 groups according to the period of denervation: 6-12 months denervation group(n= 12), 1-2 years denervation group (n = 10), 2-3 years denervation group (n = 8), and over 3 years denervation group(n=8). Another 12 specimens of normal PCAMs served as control. The patients in all groups were age- and sex-matched. The expression of myogenin protein and mRNA was studied using immunofluorescence staining and real-time PCR analysis, respectively. Results: Immunofluorescence staining showed that the positive myogenin expression was mainly found in the myonuclei of PCAMs with a denervation period less than 3 years; no positive staining was found in the myonuclei of control group. The expression of myogenin in myonuclei and the ratio of positive cells were up-regulated in the 6-12 month denervation group compared with those in the control group; the expression and the ratio peaked in 1-2 years denervation group and decreased again in the 2-3 years denervation group, but was still significantly higher than those of the control group (all P< 0.01). There was hardly any expression of myogenin 3 years after denervation. Results of RT-PCR showed no myogenin mRNA expression in the control group; the expression in 1-2 years, 2-3 years, and more than 3 years denervation groups were 4 times, 64 times, and half that of the 6-12 months denervation group, respectively (all P<0.05). Conclusion: It is indicated that there is a potential for muscle regeneration within 3 years of denervation.
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Objective: To study the morphological changes of posterior cricoarytenoid muscles (PCM) in patients with longterm denervation of recurrent laryngeal nerve (RLN), so as to provide theoretical evidence for repair of recurrent laryngeal nerve at advanced clinical stage. Methods: Thirty-eight patients with damaged RLN were divided into 4 groups according to the duration of their RLN damage: 6-12 months group (n = 12), 1-2 years group (n = 10), 2-3 years group (n = 8), and over 3 years group (n = 8). Twelve subjects with normal PCM served as control. Trichrome Masson staining and imaging analyzing system were used to quantitatively analyze the transverse section areas of myofibers, collagen fiber and connective tissues. SDH and AchE staining and cell counting method were used to analyze changes of two kinds of myofibers and motor end plate numbers at different times after denervation of recurrent laryngeal nerve. Results: The transverse areas of myofibers gradually decreased and those of collagen fibers gradually increased with the prolongation of denervation; the difference was significant between different groups (P<0.01). The ratio of transverse area of myofiber to that of collagen fibers reached the lowest level 0.5-2 years after denervation. The fibrosis of muscle obviously slowed down 2 years after denervation. The transverse section of 48% of myofibers remained 3 years after denervation, Long-term denervation resulted in the changes of muscle fiber types: the ratio of red muscles was increased and the ratio of white muscles was decreased after denervation; the difference was significant between different groups (P < 0.01). The number of motor end plate decreased with the prolongation of denervation and disappeared after 1 year. Conclusion: The morphological alteration in long-term denervation PCM indicates the worst myofibrosis occurs within 2 years of denervation, but 48%of myofibers remain 3 years after denervation. The type alteration of denervated muscles may decrease the apoptosis of skeletal muscle. The structure of myoceptors disappears within 1 year of denervation. Our experiment indicates that there is a morphological basis for regaining total or partial muscle function by nerve repair after long-term denervation.
ABSTRACT
Objective:To study the morphological changes of posterior cricoarytenoid muscles(PCM) in patients with long-term denervation of recurrent laryngeal nerve(RLN),so as to provide theoretical evidence for repair of recurrent laryngeal nerve at advanced clinical stage.Methods: Thirty-eight patients with damaged RLN were divided into 4 groups according to the duration of their RLN damage: 6-12 months group(n=12),1-2 years group(n=10),2-3 years group(n=8),and over 3 years group(n=8).Twelve subjects with normal PCM served as control.Trichrome Masson staining and imaging analyzing system were used to quantitatively analyze the transverse section areas of myofibers,collagen fiber and connective tissues.SDH and AchE staining and cell counting method were used to analyze changes of two kinds of myofibers and motor end plate numbers at different times after denervation of recurrent laryngeal nerve.Results: The transverse areas of myofibers gradually decreased and those of collagen fibers gradually increased with the prolongation of denervation;the difference was significant between different groups(P
ABSTRACT
Objective:To investigate the change in myogenin expression at different time in long-term denervated human posterior cricoarytenoid muscles(PCAMs),so as to provide a theoretical basis for timing of reinnervation.Methods: Thisty-eight specimens of denervated human PCAMs were divided into 4 groups according to the period of denervation: 6-12 months denervation group(n=12),1-2 years denervation group(n=10),2-3 years denervation group(n=8),and over 3 years denervation group(n=8).Another 12 specimens of normal PCAMs served as control.The patients in all groups were age-and sex-matched.The expression of myogenin protein and mRNA was studied using immunofluorescence staining and real-time PCR analysis,respectively.Results: Immunofluorescence staining showed that the positive myogenin expression was mainly!found in the myonuclei of PCAMs with a denervation period less than 3 years;no positive staining was found in the myonuclei of control group.The expression of myogenin in myonuclei and the ratio of positive cells were up-regulated in the 6-12 month denervation group compared with those in the control group;the expression and the ratio peaked in 1-2 years denervation group and decreased again in the 2-3 years denervation group,but was still significantly higher than those of the control group(all P