This is a randomized, double-blind, placebo-controlled, single ascending dose (SAD) study of SYH2070 injection when administered subcutaneously to healthy subjects.

Inclusion Criteria:

1. Subjects must provide informed consent before the trial, fully understand its content, procedures, and potential adverse reactions, and voluntarily sign the written ICF;
2. Sex: Male or female;
3. Age: 18-60 years (inclusive);
4. Body mass index (BMI) in the range of 19 to 30 kg•m^2 [BMI = weight/height^2 (kg•m^2)] (inclusive), with a weight of no less than 50 kg for males (inclusive) and no less than 45 kg for females (inclusive);
5. Fasting serum TG ≥150 mg/dL (1.7 mmol/L) and ≤ 500 mg/dL (5.6 mmol/L), and LDL-C ≥70 mg/dL (1.8 mmol/L) and < 190 mg/dL (4.9 mmol/L) during the screening and baseline periods;
6. Subjects must maintain stable die, exercise, and other lifestyle habits from 4 weeks prior to screening until the end of the study, with no planned changes to diet, exercise or weight loss programs;
7. Subjects must be able to communicate well with the investigator and can complete the study according to the protocol requirements.

Exclusion Criteria:

1. History of severe allergic diseases or allergic constitution (≥ 3 drug or food allergies), or known history of allergy to the investigational drug components (N-acetylgalactosamine, sodium hydroxide, phosphoric acid) or oligonucleotide drugs;
2. Use of antibody drugs and/or oligonucleotide drugs targeting PCSK9/ANGPTL3/ApoC-III within 12 months prior to screening;
3. Current and/or history of clinically significant medical conditions, including but not limited to circulatory, hematological or hematopoietic, respiratory, endocrine, urinary, digestive system diseases, neurological or psychiatric disorders, infections, tumors, severe trauma, or any other disease that should be excluded or may interfere with the interpretation of the study results, as judged by the investigator;
4. History of major surgery within 6 months prior to screening, or are scheduled to undergo major surgery during the course of the study;
5. History of bariatric surgery within 12 months prior to screening;
6. Have clinically significant abnormalities in vital signs, physical examination, electrocardiogram, and laboratory tests (excluding lipid parameters);
7. Estimated glomerular filtration rate (eGFR) <90 mL/min/1.73 m^2 at screening;
8. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), gamma-glutamyl transferase (GGT), or alkaline phosphatase (ALP) >1.5× upper limit of normal (ULN) at screening (one retest allowed within 1 week);
9. Prolonged QT / QTc interval at screening or baseline (QTcF > 450 ms);
10. Positive result for any of HBsAg, HCV antibody, syphilis antibody, and HIV antibody;
11. Blood loss or donation >200 mL within 3 months prior to screening (excluding menstruation for females), and/or platelet donation within 2 weeks;
12. Use of any drugs, health supplements, vitamins, or dietary supplements known to affect lipid metabolism within the longer of either: (a) 28 days prior to dosing; (b) 7 half-lives of the drug; (3) the duration of the agent's pharmacological effect, including but not limited to statins, fish oil, high-purity omega-3, prescription-dose niacin, fibrates, or anti-estrogen therapy;