The title is clear and completely informative. The funding organization is mentioned and it is impartial from the study team. The aim of the study is clearly described. The references are correct, new and related to the study.

But I think the novelty of the study is low because of the reference numbered 20.
The topic (the effect of MSC and exosome therapy on a rat model of liver fibrosis) and research question is described well. The method including cell culture, animal model, the process of the exosomes and western blotting are valid. The statistical analysis is described correctly. The animal grouping is confusing one of the groups in the text is missed or the sham is not described accurately (page 2, last paragraph, Eight weeks later, CCl4 treated rats were randomly assigned into four groups (n = 12): the liver fibrosis group rats were injected with PBS alone the hBM-MSCs group (positive control) rats were injected with 1 × 106/500 μl hBM-MSCs through the tail vein; the hBM-MSCs-Ex group rats were injected with 250 mg hBM-MSCs-Ex (harvested from 1 × 106 hBM-MSCs) in 500 μL PBS through the tail vein; the sham group rats were treated with PBS alone ) All tables and figures are clearly presented and correctly labeled. The results are rational and statistically significant.
The result related to IF that is mentioned in the method section is missed in this section. In the text, page 7 paragraph 1 line 12, the results is no correctly presented according to figure 4d.
The results are completely interpreted without magnificence. The aim of the study is answered and new references are included in the discussion that is necessary. The limitations of the study are not mentioned.
Major point 1. the novelty of the study is low because of the reference numbered 20 minor points 1. The animal grouping is confusing one of the groups in the text is missed or the sham is not described accurately (page 2, last paragraph) 2. The result related to IF that is mentioned in the method section is missed in this section 3. In the text, result section the page 7 paragraph 1 line 12, the results is no correctly presented according to figure 4d