RNA was extracted from Achilles tendons using Trizol/chloroform. cDNA was synthesized by reverse transcription using the SuperScript VILO master mix (Cat. # 11755050, Invitrogen). The TaqMan Array Mouse Immune Panel (Cat. # 4414079, Thermo Fisher) with Taqman Fast Advanced Master Mix (Cat. # 4444556, Thermo Fisher) was used to screen 92 genes related to immune response. Gene expression was normalized to Gapdh and analysed using the 2−ΔΔCt method relative to uninjured control tendons. qPCR was carried out by Mount Sinai’s core facilities using SYBR PCR Master Mix (Cat. # 4309155, Thermo Fisher) and gene expression calculated using the 2−ΔΔCt method relative to Gapdh and carrier-treated control tendons at D3. Primers for Il1β (FWD: AGTTGACGGACCCCAAAAGAT; REV: GTTGATGTGCTGCTGCGAGA) and Il10 (FWD: ATTTGAATTCCCTGGGTGAGAAG; REV: CACAGGGGAGAAATCGATGACA) were used. Tendon gene primers were previously described (7 (link)).