Light and electron microscopic study on the effect of colchicine on skeletal muscle of albino rat

ABSTRACT

Colchicine has anti-inflammatory action, thus it is used in the treatment of gouty arthritis, familial Mediterranean fever, amyloidosis, dermatosis and some cutaneous diseases. This study was designed to investigate the effect of colchicine on skeletal muscle of the albino rat. Twenty eight adult rats [20 females and 8 males] were used. Only 12 females were allowed to get pregnant. All the animals were divided into 5 groups. The 1st group contained the control offsprings of 4 pregnant rats. The 2nd group contained the nontreated offsprings of 4 treated pregnant rats. Each pregnant rat was treated daily by a single oral dose [0.03 mg] of colchicine for 5 successive weeks, from the first day of pregnancy up to the end of the 2nd week after delivery.The 3rd group, contained treated offsprings of non treated four mothers. Each offspring was treated daily by a single oral dose [0.003 mg] of colchicine for 5 successive weeks from the beginning of the 2nd week up to the end of the 6th week of post natal life. The 4th group contained 8 control adult rats [4 males and 4 females]. The 5th group contained 8 treated adult rats [4 males and 4 females]. Each rat was treated by a daily oral dose [0.03 mg] of colchicine for 5 successive weeks. At the end of the determined period of the experiment, the gastrocnemius muscles of all groups were collected and were prepared for light and electronmicroscopic study- Light microscopic examination of all treated groups displayed widening of the intercellular spaces with shrinkage and disarray of the muscle fibres. Some myofibers in the 2nd and 3rd groups comprised degenerated nuclei. Moreover, all treated groups exhibited marked reduction of the collagenous supporting tissue. Under the electron microscope, the 2nd group revealed severe ultrastructural changes, while the 3rd group revealed marked changes. However, the 5th group revealed moderate changes. In all treated groups there was irregularity of the sarcolemmal membrane, disorientation and disorganization of the muscle fibers with focal areas of myofilaments loss or fragmentation. Mitochondrial degeneration, electron dense bodies and increased glycogen granules were also observed. The tubular system were either dilated or disrupted. Moreover, vacuolar myopathy due to the presence of the autophagic vacuoles was the characteristic myopathetic changes induced by colchicine. Lysosomes and streaming or degeneration of the Z bands were also regarded. Furthermore other myotoxic changes were only recognized in the 2nd and 3rd groups. These changes included loss of cross striations of myofibrils, loss of the sarcomeric structure and the presence of large fat globules in the sarcoplasm. In addition, lacking of most of the myofibrils and its replacement by granular pattern was only observed in the 2nd group