Effect of tenotomy on extensor digitorum longus muscle in Sprague Dawley rats.

The effect of tenotomy on Extensor Digitorum Longus (EDL) muscle, brought about by removal of anterior tibialis muscle was studied in the rat. Hypertrophy as well as hyperplasia of the muscle fibres were observed following tenotomy of intact muscle. The transplanted muscle regenerated after tenotomy in the form of a flat strap. The weight, length, breadth and total muscle area of intact muscle increased but decreased in transplanted muscle following tenotomy. The number of muscle fibres/microscopic field increased during the entire experiment in intact muscle after tenotomy, while in transplant the number of fibres first decreased and then increased. The diameter of intact and transplanted muscle increased after tenotomy. The number and diameter of nuclei was normalized at the end of experiment in both groups. The DNA and RNA content was increased in intact muscle after tenotomy. In transplant DNA and RNA content first increased but than decreased. The protein content was increased in intact muscle at the end of the experiment but decreased in transplant after tenotomy.