ABSTRACT
Aim To observe the changes of diaphragm contractility and cytoskeletal proteins titin,nebulin and sarcoplasmic reticulum Ca~(2+)-ATPase gene expressions in adriamycin-induced cytotoxicity in rats.Methods The animal models of diaphragm damage were duplicated by injecting adriamycin into abdominal cavity one time.Forty male sprague-dawley rats were randomly divided into four groups(n=10):Three groups received adriamycin in low,middle and high dosage(10,20 and 40 mg·kg~(-1))respectively.Meanwhile,the normal saline was given to rats in control groups.Three days later,these rats were killed,and the diaphragm was removed by thoracotomy.The diaphragm contractility was assessed in isolated diaphragm strips perfusion by these paramemters including peak twitch tension(Pt),maximum tetanic tension(Po),time to peak contraction(CT),half relaxaion time(1/2RT),maximal rates of contraction(+dt/dt_(max))and maximal rates of relaxation(-dt/dt_(max)).The expressions of titin,nebulin and sarcoplasmic reticulum Ca~(2+)-ATPase(SERCA)at mRNA level were detected by RT-PCR analysis.Results In contrast to those in control group,Po,Pt,±dt/dt_(max) in the adriamycin group were lower(P<0.01);CT,1/2RT in the adriamycin group increased significantly(P<0.01).The levels of titin,nebulin and SERCA gene expressions in middle-dose group were lower than those in control group(P<0.01).Conclusions The mRNA levels of titin,nebulin and SERCA of diaphragm are down-regulated in adriamycin-induced cytotoxicity in rats.It may be associated with the decline of diaphragm contractility.
ABSTRACT
Nemaline myopathy (NM) is a congenital disease that leads to hypotonia and feeding difficulties in neonates. Some cases have a more benign course, with skeletal abnormalities later in life. We analyzed a series of eight patients with NM obtained from a retrospective analysis of 4300 muscle biopsies. Patients were classified as having the typical form in five cases, intermediate form in two cases and severe form in one case. Histochemical analysis showed mixed rods distribution in all cases and predominance of type I fibers in five cases. Immunohistochemical analysis showed abnormal nebulin expression in all patients (four heterogeneous and four absent), homogeneous desmin expression in four cases, strongly positive in three and absent in one, fast myosin expression in a mosaic pattern in six cases and absent in two cases. There was no specific relation between these protein expression patterns and the clinical forms of NM.
Miopatia nemalínica (NM) é uma doença congênita que leva a hipotonia e dificuldade de sugar em neonatos. Alguns casos possuem uma evolução benigna, com deformidades ósseas tardias. Nós analisamos uma série de oito pacientes com NM obtidos da análise retrospectiva de 4300 biópsias musculares. Os pacientes foram classificados como forma típica em cinco casos, forma intermediária em dois casos e forma severa em um caso. Análise histoquímica mostrou distribuição mista dos rods em todos os casos e predominância de fibras tipo I em cinco casos. Análise imuno-histoquímica mostrou expressão anormal da nebulina em todos os pacientes (quatro heterogênea e quatro ausente), expressão homogenea da desmina em quatro casos, fortemente positiva em tres e ausente em um, expressão da miosina (rápida) com padrão em mosaico em seis casos e ausente em dois casos. Não há relação específica entre a expressão destas proteínas e as formas clínicas da NM.
Subject(s)
Child , Child, Preschool , Female , Humans , Infant , Male , Desmin/metabolism , Immunohistochemistry , Muscle Proteins/metabolism , Muscles/pathology , Myopathies, Nemaline/pathology , Myosins/metabolism , Biopsy , Electromyography , Myopathies, Nemaline/metabolism , Retrospective Studies , Severity of Illness IndexABSTRACT
OBJECTIVE: bjective: By identifying the unknown substance responsible for binding with nebulin SH3 domain within the sarcomeric Z-line, we tried to find out Z-line structure which plays an important role on muscle contraction and maintenance of muscle funtion. METHOD: First, the bait plasmid was made by binding the DNA binding domain of Gal4 protein of yeast and the SH3 domain. Second, library plasmid was made by binding activation domain and human skeletal cDNA library. Then, the base sequence of the clone, produced by combining the two proteins expressed by transgenically converted plasmid in yeast, was analyzed. RESULT: We screened out six true positive clones and analyzed the base sequence of the two of six clones. We identified them to be alpha-actinin2. CONCLUSION: We can theorize that Neublin SH3 domain and alpha-actinin2 plays a vital role for the integration of Z-line. Thus, this is an important data in further studying muscle functions, mechanisms, and muscular disease as well.