Original article Laser biostimulation of cartilage: in vitro evaluation P. Torricelli 1 *, G. Giavaresi 1 , M. Fini 1 , G.A. Guzzardella 1 , G. Morrone 1 , A. Carpi 2 , R. Giardino 1,3 1 Experimental Surgery Department, Istituto di Ricerca Codivilla-Putti, Istituti Ortopedici Rizzoli, Servizio di Chirurgia Sperimentale, Via di Barbiano, 1/10, 40136 Bologna, Italy; 2 Department of Ageing and Reproduction, University of Pisa, Pisa, Italy; 3 Chair of Surgical Pathophysiology, University of Bologna, Bologna, Italy (Received 25 August 2000; accepted 4 October 2000) Summary – An in vitro study was performed to evaluate the laser biostimulation effect on cartilage using a new gallium-aluminium-arsenic diode laser. Chondrocyte cultures were derived from rabbit and human cartilage. These cells were exposed to laser treatment for 5 days, using the following parameters: 300 joules, 1 watt, 100 (treatment A) or 300 (treatment B) hertz, pulsating emission for 10 minutes, under a sterile laminar flow. Control cultures (no treatment) received the same treatment with the laser device off. Cell viability was measured by MTT assay at the end of the laser treatment and then after 5 days. Neither rabbit nor human cultured chondrocytes showed any damage under a light microscope and immunostaining control following laser treatment. The MTT test results indicated a positive biostimulation effect on cell proliferation with respect to the control group. The increase in viability of irradiated chondrocytes was maintained for five days following the end of the laser treat- ment. The results obtained with the Ga-Al-As diode laser using the above tested parameters for in vitro biostimulation of cartilage tissues provide a basis for a rational approach to the experimental and clinical use of this device. © 2001 Éditions scientifiques et médicales Elsevier SAS cartilage / in vitro / laser biostimulation Low-power laser medical devices are increasingly being employed in antalgic, therapeutic, and surgi- cal fields. Some different types of lasers evolved for specific applications [3] and many authors tested laser biostimulation effects in in vitro and in vivo experi- mental studies before clinical use [1]. In the orthopaedic field, several experimental meth- ods and different laser devices were used to evaluate the effects of laser irradiation on cartilage as well [19]. In fact, healing of damaged cartilaginous tis- sues is an important aim, and all of the methods that can improve cartilage repair processes arouse great interest. Some of the studies on laser effects on the cartilaginous tissue showed different and even oppos- ing results. In some cases, laser biostimulation had no relevant effect [15] or inhibited cell growth [10], while in other studies it promoted a significant stimu- lation of the cartilage matrix synthesis [16, 18]. The reported differences can be explained by the wide range of laser radiation effects on biological tissues, due to the intrinsic characteristics of the different devices. Additionally, modulation of the selected parameters according to the type of tissue to treat can significantly modify results [2]. The aim of this study was to evaluate the in vitro effect of a new gallium, aluminum and arsenic (Ga- Al-As) diode laser on chondrocyte cultures, by com- paring different work parameters tested on cells derived from both animal (rabbit) and human articu- lar cartilage. *Correspondence and reprints. E-mail address: paolapaola..torricelli@ior.it (P. Torricelli). Biomed Pharmacother 2001 ; 55 : 117-20 © 2001 Éditions scientifiques et médicales Elsevier SAS. All rights reserved S0753332200000251/FLA