Exposure to air during surgery inhibits cellular activity in flexor tendons

In order to investigate the cellular effects of exposure to air during surgery and to compare the effects of simultaneous irrigation with physiological saline, the deep flexor tendons of both forepaws of 12 rabbits were surgically exposed. In one experiment, the extent of surgical exposure and, in a second experiment, the time of exposure was evaluated. Treated segments of the flexor tendons were collected and labelled in vitro for determination of the ability to synthesize DNA, proteoglycan, collagen and non-collagen protein. With increasing surgical exposure in vivo, an increasing rate of cellular proliferation was observed in segments of the exposed deep flexor tendons examined in vitro. Synthesis of matrix components and the rate of cellular proliferation were reduced by 50% after 40 to 100 minutes of exposure to air and by nearly 100% after 120 minutes of exposure. In contrast, irrigated tendons retained their cellular capacity to proliferate.