Abstract
INTRODUCTION: Collagen-based materials differ in absorption time, biodegradation patterns, and inflammatory cell infiltration. This study aimed to evaluate the biocompatibility and biodegradation of native, differently processed, and cross-linked porcine collagen membranes implanted in the subcutaneous tissue of rats, following ISO 10993-6:2016. METHODS: Sixty Sprague-Dawley rats were randomly divided into four groups: Group 1 (lyophilized 3 % porcine type I collagen membrane), Group 2 (lyophilized 3 % porcine type I collagen membrane, dehydrothermal [DHT]), Group 3 (1,4-butanediol diglycidyl ether [BDDE] cross-linked, lyophilized 3 % porcine type I collagen), and Group 4 (BDDE cross-linked, lyophilized 3 % porcine type I collagen, DHT). The experimental periods were 1, 2, 4, 8, and 12 weeks, with three animals per group per period. After each period, specimens were extracted and analyzed for membrane structure, biodegradation, cell infiltration, angiogenesis, tissue integration, and foreign body reaction using histological staining and scoring according to ISO 10993-6:2016. RESULTS: The cross-linked collagen membrane groups maintained their porous structure, with cell infiltration and blood vessel formation observed within this structure. Non-cross-linked collagen membranes (Group 1) appeared as lumps under the subcutaneous tissue and exhibited minimal or no response throughout the observation periods. Groups 2 and 4 biodegraded the fastest. Group 2 membranes were not detected in the subcutaneous tissue at 8 weeks, classified as a slight response. Cross-linked collagen membranes in all groups showed a slight response, whereas Group 4 exhibited a moderate response (11.0-16.9) only at 12 weeks. The tissue response to collagen membranes in all groups aligned with physiological inflammatory processes, scoring from minimal or no response (0.0-5.9) to slight response (6.0-10.9), confirming their biocompatibility. CONCLUSIONS: Cross-linking methods, temperature, and chemical reagents influence collagen membrane properties. Cross-linked collagen formed a porous structure, and high-temperature DHT cross-linking accelerated the biodegradation of the collagen membrane.