Background: Granulation tissue is formed during the proliferative phase of wound healing. In the presence of granulation tissue, the process of epithelialization can take place. Disturbance in the formation of granulation tissue, especially hyper-granulation, will result in an abnormal wound healing process. Antihistamines have been shown to have an effect on abnormal wound tissue fibroblasts and reduce collagen synthesis both by topical administration in vivo and in vitro culture. This study aimed to investigate the effect of oral antihistamines on granulation tissue formation, collagen deposition, and angiogenesis involved.
Method: The study design used was an experimental randomized post-test only. Thirty-two rats were divided into 2 groups, wherein group 1 was treated as a control while those in the second group were given oral diphenhydramine with a dose according to body weight. Full-thickness wounds were made on the back of all rats. The treatment was carried out every day for 7 days. On the 7th day, granulation tissue specimens were taken with an excisional biopsy from the wound. From each granulation tissue sample, data taken were the granulation tissue thickness, collagen density, and the number of capillaries formed.
Results: Using an independent T-test, the mean thickness of granulation tissue in the treatment group was significantly smaller than the control group (215.82 ± 44.73 μm vs. 304.43 ± 58.61 μm, p<0.005). Mann-Whitney test revealed that the mean number of capillaries in the treatment group was significantly less than the control group (38.11 ± 5.31 vs. 69.66 ± 11.81, p<0.005). Kruskal-Wallis test revealed that the collagen density of the treatment group was significantly smaller than the control group (p<0.0001).
Conclusion: Administration of oral antihistamines can inhibit the formation of granulation tissue in full-thickness wounds and also reduce collagen density and angiogenesis. This can serve as a reference for the effect of oral antihistamines on wound healing, especially in the process of granulation tissue formation.