BACKGROUND: Tendon cells possess collagen-secreting function, which plays an important role in the wound healing and adhesion. Little is known about the biological effects of lactate on tendon cells. OBJECTIVE: This study was designed to study the proliferation and collagen production of tendon sheath fibroblasts,epitenon tenocytes, and endotenon tenocytes and investigate the effect of lactate on cell proliferation, collage production and secretion of transforming growth factor- β1(TGF- β 1),basic fibroblast growth factor (bFGF), and interleukin-8 (IL-8) by each of these 3 cell types in rabbit flexor tendon.DESIGN, TIME AND SETTING: This study, a randomized controlled animal experiment, was performed at the Animal Laboratory Center, Affiliated Hospital of Qingdao University Medical College between September 2005 and July 2006.MATERIALS: Six adult New Zealand clean rabbits of either gender were included in the present study.METHODS: Tendon sheath fibroblasts, epitenon tenocytes, and endotenon tenocytes were isolated from rabbit flexor tendon and cultured. Each cell type was identified by observing morphological structure through methylene blue staining.Three types of cells were cultured with media supplemented with 25 mol/L lactate to obtain cell number. The collagen production and secretion of TGF- β 1, b-FGF and FL-8 were compared after adding culture media supplemented with 25, 50,100, and 200 mmol/L lactate, respectively. At the same time, the above-mentioned indices measured after adding medium were compared with those measured without adding lactate.MAIN OUTCOME MEASURES: Type Ⅰ, Ⅱ, and Ⅲ collagen production was detected by immunohistochemistry; The effects of different concentrations of lactate on type Ⅰ collagen production as well as secretion of TGF- β 1,b-FGF, and IL-8by an enzyme linked immunosorbent assay (ELISA).RESULTS: 25 mmol/L lactate reduced 3 types of cultured cells. There was no significant difference in the cell number among the 3 types of cells (P > 0.05) Lactate produced more type Ⅰ, Ⅱ ,and Ⅲ collagen tissue compared to not adding lactate (P < 0.05) When lactate concentration increased to 50 mmol/L, type Ⅰ collagen reached its peak level in the 3 types of cells. There was significant difference in type Ⅰ collagen compared with lactate concentration was 0 mmol/L(t = 4.58, 3.97,3.16, P < 0.01 ) . When lactate concentration increased to 100 mmol/L and 200 mmol/L, type Ⅰ collagen was noticeably decreased. When lactate concentration was 25 mmol/L in the 3 types of cells, the secretion of TGF- β 1 and bFGF was increased and the secretion of IL-8 was decreased. There was significant difference compared with not adding lactate (P <0.05).CONCLUSION: Lactate can increase the collagen production of tendon sheath fibroblasts, epitenon tenocytes, and endotenon tenocytes. The increasing degree of collagen production is related to lactate concentration, in particular at 50 mmol/L. Such a stimulation may be related to the increase of TGF- β 1 and bFGF and the decrease of IL-8 secretion.

0.05) Lactate produced more type Ⅰ,Ⅱ,and Ⅲ collagen tissue compared to not adding lactate(P