The purpose of this study is to evaluate the safety and efficacy of human TH-SC01 cell injection for the treatment of complex perianal fistulas

This study is a phase Ⅰ/Ⅱ study, Phase 1 was the dose increment phase, and phase 2 was the expansion phase

Inclusion Criteria:

1. Signed informed consent.
2. Subjects aged between 18 and 70, both male and female.
3. The subject was clinically diagnosed as complex anal fistula. The diagnostic criteria for complex anal fistula were adopted by the 2016 American Association of Colorectal Surgeons Guidelines for the Treatment of Perianal Abscess, Anal Fistula and Rectovaginal Fistula.
4. The subjects had received conventional treatment for anal fistulas
5. All subjects and their partners were not planning to have a child from screening to the end of the trial and agreed to use effective non-drug contraception during the trial.

Exclusion Criteria:

1. Subjects with anal fistula in the acute infection period.
2. Subjects with abscess or collections >2 cm.
3. Subjects with abnormal laboratory results: liver function: total bilirubin >=1.5 × ULN, and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) >=2 × ULN; renal function: creatinine clearance below 60 mL/minute calculated using Cockcroft-Gault formula or by serum creatinine >=1.5 × upper limit of normal (ULN).
4. Subjects with malignant tumors or a history of malignant tumors.
5. Subjects with severe, progressive, uncontrolled hepatic, hematological, gastrointestinal (except Crohn's disease), endocrine, pulmonary, cardiac, neurological, psychiatric, or cerebral diseases.
6. Serum virology test (HBeAg, HCV antibody, HIV antibody, Treponema pallidum antibody) positive.
7. Subjects allergic to gentamicin sulfate, anesthetics or contrast media.
8. Subjects allergic to MRI contrast.
9. Subjects who has major surgery or severe trauma within 6 months prior to the screening period.
10. Subjects who has received any investigational drug within 3 months prior to the screening.
11. Subjects deemed inappropriate by the investigator to participate in this clinical trial.
12. The female participant who is pregnant, or is lactating.