A priori unaltered literature audit / pre-screening protocol protocol for resolving the "28-Study Paradox" of cerebrovascular targeted small extracellular vesicles and vascular smooth muscle cell functional research

Five core files are included: PRISMA-P 2015 compliant full review protocol, dual Chinese-English database search strategies, blank Weighted Quality Matrix (WQM) scoring & data extraction template aligned with MISEV2023 standards, PRISMA 2020 checklist for systematic review without meta-analysis, and a README catalogue file.

Due to regional network access restrictions, prospective registration on international repositories (OSF, Zenodo) was unavailable; this ScienceDB archive is established to satisfy PRISMA 2020 open science transparency requirements, providing traceable pre-defined eligibility criteria, quality assessment rules and statistical analysis plans for peer review verification. All documents are retained in their original version locked before screening.