ABSTRACT
Objective To study the possible mechanisms of influence of different doses of UVA1 on the development of hypertrophic scar in rabbit ears induced by excision of full-thickness skin. Methods A hypertrophic scar model was established by excision of full-thickness skin on the ventral surface of rabbit ears.A total of 24 New Zealand white rabbits were randomly and equally divided into 4 groups to receive UVA1 radiation on the left ear immediately (U0 group), 1 month (U1 group), 2 months (U2 group) and 3 months (U3 group) after the excision, respectively, and each group were classified into two subgroups to be irradiated with UVA1 of 60 (middle) and 110 (high) J/cm2, respectively, for 30 sessions. The right ears served as the control without irradiation. Skin samples were obtained from the ears of rabbits before the first and after the last irradiation, transmission electron microscopy (TEM) was used to observe the ultra-structure and morphology of collagen fiber and fibroblasts, and immunohistochemical staining was performed to measure the expressions of matrix metalloproteinases (MMP)-1, tissue inhibitor of metalloproteinase (TIMP)-1, transforming growth factor (TGF)-β1, proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin (α-SMA) in skin samples. Results Compared with the unirradiated skin, irradiated skin showed higher expression levels of MMP-1 (P ＜ 0.05), which were 10.43 ± 1.61 and 11.16 ± 1.57 in middle- and high-U1 group, 8.63 ± 2.61 and 7.33 ± 1.58 in middle- and high-U2 gorup, 5.74 ± 1.43 and 3.11 ± 0.27 in middle- and high-U3 group respectively. The expression level of TGF-β1 in irradiated skin was 12.51 ± 4.13 and 12.02 ± 5.02 in middle- and high-U1 group, respectively, 18.74 ± 6.42 and 19.69 ± 4.52 in middle- and high-U2 group, respectively, 20.51 ± 1.78 and 29.45 ± 6.55 in middle- and high-U3 group, respectively. A significant decrease was observed in the expression of PCNA in irradiated skin in middle- and high-U1 group (2.67 ± 0.44 and 2.04 ± 0.65), middle- and high-U2 group (4.50 ± 0.97 and 5.82 ± 0.68), middle- and high-U3 group (7.45 ± 1.47 and 8.16 ±1.07) in comparison with unirradiated skin (all P＜ 0.05). There was a lower expression of TIMP-1 in irradiated skin of high-U1, -U2, and -U3 group (12.74 ± 4.58, 15.17 ± 3.26, 20.72 ± 3.31, all P＜ 0.05) as well as α-SMA in that of high-U1, middle-U1 and high-U2 group (1.33 ± 0.34, 2.04 ± 0.20, 3.60 ± 1.75, all P＜ 0.05) compared with the unirradiated skin. Further more, a significant increment was observed in the expressions of TGF-β1 (23.90 ± 2.92, P ＜ 0.05) in irradiated skin of high-U0 group, PCNA(7.42 ± 0.65 and 7.59 ± 0.31 ),TIMP-1 (29.82 t 1.94 and 33.51 ± 1.19) and α-SMA (6.31 ± 0.61 and 2.97 ± 0.56) in irradiated skin of middle- and high-U0 group, but a decline in the expression of MMP-1 (.25 ± 0.38, P＜ 0.05) in irradiated skin of high-U0 group in comparison with the unirradiated skin. TEM showed that the collagen fiber diameter turned small, and fibroblasts, most of which were quiescent, showed a reduction in cytoplasm volume with the presence of immature organelles, after high-dose UVA1 irradiation. Conclusions The therapeutical effect of UVA1 on scar may be realized by accelerating the degradation of matrix proteins and decelerating the proliferation of fibroblasts and myofibroblasts via downregulating the expressions of TGF-β1, TIMP-1 and α-SMA and upregulating the expression of MMP-1. However, the results would be opposite if the interference with UVA1 irradiation is given at the early stage of wound healing.
ABSTRACT
Objective To study the efficacy of rituximab in the treatment of pemphigus vulgaris (PV) and its underlying mechanism. Methods A 38-year-old female with PV presented with refractory, painful oral ulcers and erosions. Since she was poorly responsive to prednisone 80 mg daily, intravenous ritu-ximab of 500 mg once a week was given for successive 3 weeks followed by 5 successive days of intra-venous gamma globulin at a dose of 400 mg/kg per day, and a total of two treatment sessions were conducted. ELISA was used to detect the serum titer of anti-Dsg3 antibodies and their IgG subtypes (IgG1 and IgG4) as well as serum level of interferon-gamma (IFN-gamma), interleukin-4 (IL-4), interleukin-10 (IL-10). Results Three months after the end of two treatment sessions, the symptom was obviously improved, and lesions subsided; alter another 1 month, clinical symptom fully disappeared. During the 1-year follow-up, no lesions recurred. The anti-Dsg3 antibody titer was 253.33 U/mL before treatment, plateaued at 250 U/mL within 4 weeks after the initial infusion, decreased till 3 months after the withdrawal, and reached 26.06 U/mL 7 months after the withdrawal, and remained within normal range till the time of this writing. The serum titer of IgGl subclass of anti-Dsg3 antibodies dropped dramatically fight after the first infusion, but that of IgG4 subclass remained at a high level at early stage of medication, began to decline until 3 months after the with-drawal, and finally reached the normal range following clinical remission. Also, serum level of IFN-garnma and IL-10 correlated with the severity of PV. Conclusions Combined rituximab is effective for the control of PV, likely by eliminating Dsg3-specific antibodies, especially IgG4 subclass of them.
ABSTRACT
Objective To study the effects of different doses of UVA1 on the development of hypertrophic scar in rabbit ears induced by excision of full-thickness skin. Methods A hypertrophic scar model was established by excision of full-thickness skin (2 cm×5 cm) on the ventral surface of rabbit ears. A total of 18 New Zealand rabbits were randomly divided into 3 equal groups to receive UVA1 radiation on the left ears immediately, 1 month, and 2 months after the excision, respectively, and every group were classified into two subgroups to be irradiated with 60 and 110 J/cm2 of UVA1, respectively, for 30 sessions. The right ears served as control without irradiation. HE staining and Masson staining were used to examine the dermal thickness and collagen content in scar, respectively. Results Compared with pre-irradiation, the dermal thickness (t = 5.85, 4.94, respectively, both P＜0.05) and collagen content (t = 6.50, 8.02, respectively,both P＜0.05) significantly decreased in scar irradiated with UVA1 of 110 J/cm2 one and two months after the excision. The difference value in dermal thickness and collagen content at the beginning and at the end of the study significantly differed between irradiated and non-irradiated ears in the rabbits treated with UVA1 of 110 J/cm2 (P＜0.05). The effects of UVA1 on dermal thickness and collagen content were dose-dependent (P＜0.05). On the contrary, the dermal thickness and collagen content markedly increased in scars of rabbits irradiated with UVA1 immediately after the excision (P＜0.05 ). Conclusions To begin UVA1 exposure of hypertropic scar in rabbits after epithelialization may lead to the softening of scar, thinning of skin, and decrease of collagen content. However, immediate irradiation with UVA1 after wound could not prevent the development of hypertrophic scar in rabbits, in contrast, it exacerbated the severity of scar.