Open AccessIntratendinous Injection of Hyaluronate Induces Acute Inflammation: A Possible Detrimental Effect
Author(s) -
PoTing Wu,
IMing Jou,
Li-Chieh Kuo,
Fong-Chin Su
Publication year - 2016
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0155424
Subject(s) - neovascularization , inflammation , medicine , saline , achilles tendon , tendon , m2 macrophage , pathology , surgery , macrophage , chemistry , angiogenesis , biochemistry , in vitro
Hyaluronate (HA) is therapeutic for tendinopathy, but an intratendinous HA injection is usually painful; thus, it is not suggested for clinical practice. However, there are no studies on the histopathological changes after an intratendinous HA injection. We hypothesized that an HA injection would induce more-acute inflammation than that induced by an injection of phosphate buffered saline (PBS). Thirty-two rats were randomly divided into 4 post-injection groups (n = 8): day 3 , day 7 , day 28 , and day 42 . HA (0.1 c.c.) was, using ultrasound guidance, intratendinously injected into each left Achilles tendon, and PBS (0.1 c.c.) into each right one. For each group, both Achilles tendons of 3 control-group rats (n = 6) were given only needle punctures. The histopathological score, ED1+ and ED2+ macrophage densities, interleukin (IL)-1β expression, and the extent of neovascularization were evaluated. In both experimental groups, each Achilles tendon showed significant histopathological changes and inflammation compatible with acute tendon injury until day 42 . The HA group showed more-significant (p < 0.05) histopathological changes, higher ED1+ and ED2+ macrophage density, and higher IL-1β expression than did the PBS group. The neovascularization area was also significantly (p < 0.05) greater in the HA group, except on day 3. Both HA and PBS induced acute tendon injury and inflammation, sequential histopathological changes, ED1 + and ED2 + macrophage accumulation, IL-1β expression, and neovascularization until post-injection day 42 .HA induced more-severe injury than did PBS. Therefore, an intratendinous HA injection should be avoided.