To Evaluate the Safety, Tolerability, and Pharmacokinetic Characteristics of JMKX003142 Injection Administered Randomly, Double-blind, Placebo-controlled, Single-ascending Dose and Multiple-ascending Doses in Chinese Healthy Adult Subjects

Inclusion Criteria:

1. Male and female subjects aged 18-45 years (including boundary values).
2. Able to sign a written informed consent form.
3. Physical examination, clinical laboratory examination value, Virology examination, vital signs and ECG examination are confirmed by the researcher to be normal or abnormal without clinical significance
4. The subjects have a thorough understanding of the study content, process, and potential adverse effects, and are willing to complete the study according to the requirements of the experimental protocol

Exclusion Criteria:

1. Had or currently have serious clinical diseases related to circulatory system, respiratory system, digestive system, nervous system, endocrine system, blood lymphatic system, genitourinary system or psychiatry, as well as habitual constipation, gastrointestinal bleeding history, which is judged to be inappropriate for the study by the investigators
2. Participants in any other clinical study within 3 months prior to the first administration of this study
3. The investigators believe that the subject has other factors that are not suitable for participating in this experiment
4. Pregnant or lactating women