Body weight changes among groups.

In the Ad-EM2 group, on the 5th, 7th, and 10th day after intrathecal administration, the body weight increased significantly compared to the Ad-EGFP and the NS groups (^bP>0.0001), suggesting that EM2 expressed by Ad-EM2 reduced the loss of body weight in morphine dependent rats. Endomorphine-2 was indicated as EM2; adenovirus with EM2 was indicated as Ad-EM2; adenovirus with enhanced green fluorescence protein was indicated as Ad-EGFP; normal saline group with subcutaneous morphine injection and intrathecal NS administration was indicated as NS; Sham group with subcutaneous NS injection and intrathecal NS administration was indicated as Sham.