Protein A were even more potent in combination, and the “triple therapy” of VEGF, PDGF, and PlGF both improved wound healing and remained at the site of administration for significantly longer than wild-type growth factors.
断句我都不会断了

divide and conquer
1 Protein A were even more potent in combination, and
2 the “triple therapy” of VEGF, PDGF, and PlGF both 主语
A improved wound healing and 两个谓语
B remained at the site

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你误解了 both 的意思，
说的是 improved 和 remained
不是说的主语。

protein A在组合中甚至更强效。VEGF，PDGF和PIGF的“三联疗法”不仅能改善伤口愈合，而且其在用药部位的停留时间明显比野生型生长因子更长。

另，现在的机翻已经很厉害的了。下图是有道翻译

我平时不帮人翻译。暂且例外
protein A组合起来强度更高。而且VEGF，PDGF和PIGF的“三联疗法”不仅能改善伤口愈合，在用药部位的停留时间明显也比野生型生长因子更长。