Objective:To explore the intramuscular nerve effect on the recovery of lacerated muscle. Methods:thirty (30) healthy New Zealand rabbits were involved in the study and randomly divided into groups A and B.The right musculus rectus femoris of the animal was chosen as the lacerated skeletal muscle model with the contralateral muscle as sham control. Group A underwent muscle laceration with the intramuscular nerve microsurgical repaired and muscle repaired;group B only with muscle repaired. After a postoperative period of 28weeks

measured the muscle wet weight and the muscle strength of musculus rectus femoris by electrical stimulation test and observed the change of morphology by Hematoxyline/eosin stain

Masson stain

NADH-TR stain and mATPase stain. Compared the difference of two groups through t-test and ANOVA to decide the effects of intramuscular nerve effect on muscle injury and repair. Results:At 28 weeks postoperative

Compared with the controls

wet weight and isometric contraction of musculus rectus femoris reduced in the intramuscular neurotmesis group (P < 0.05)

Group B was poorly recovered(P < 0.05)in Cross-sectional area of type Ⅰ

Ⅱa and Ⅱb

and showed significant muscle atrophy

adipose infiltration

fibrosis

and few regenerating muscle fibers compared to the contralateral muscle. Compared with the controls in the group of the intramuscular nerve microsurgical repaired

cross-sectional area of type Ⅱ b was not good (P < 0.05). The other was mostly well recovered .Conclusion:Intramuscular nerve could promote muscle fiber regeneration of lacerated muscle

lighten muscle atrophy and fibrosis

and restore the muscle morphous and construction of muscle fiber type

thus resulting in better functional recovery.