Objective    To investigate the activity of gastrocnemius muscle after acellular nerve transplantation with microencapsulated peripheral nerve tissue to repair sciatic nerve gap in dogs.     Methods    Twelve dogs were selected and divided randomly into four groups with three in each. Both sciatic nerves of the dogs in group A were cut and chemically extracted to make acellular nerves. Acellular nerves were transplanted into the dogs of groups B and C to bridge 30 mm sciatic nerve gaps

and additionally microencapsulated peripheral nerve were added in group B. Autograft was used for repairing the defects in group D. The motor function of operated limbs were observed regularly after operation. Six months after operation

motor conduction velocity of the specimens of sciatic grafting nerve segment were observed

and the gastrocnemius muscle of both sides were obtained and performed succinic dehydrogenase (SDH)

synaptophysin (SYP) and motor end plate histochemical staining

and sciatic nerve 1 cm from distal end stoma were obtained and underwent Masson

Luxol fast blue and NF200 staining.     Results    All the dogs in groups B

C and D were involved in the results analysis without loss. Image analysis indicated the optical density and the cross section area of gastrocnemius muscle

area and optical density of synaptophysin

area and optical density of motor end plate in group B showed statistically significant difference compared with those in group C

but no significant difference with those in group D. The results of motor function recovery of operated-limb

electrophysiological examination and morphologic observations of sciatic nerve were all consistent with the detections of gastrocnemius muscle.     Conclusion    The gastrocnemius muscle may be again innerved by nerve

and the muscle atrophy is significantly alleviated after acellular nerve transplantation with microencapsulated peripheral nerve tissue for repairing sciatic nerve gap. The regeneration of nerve was better after the combined transplantation than only acellular nerve transplantation

so the combination of acellular nerve and microencapsulated peripheral nerve tissue may be a useful substitute of autograft for nerve repair.