Role and mechanism of Vγ4 T cell depletion in epidermal tissue repair after ultraviolet damage to mouse skin
Objective To explore the role and mechanism of Vγ4 T cell depletion in epidermal tissue repair after ultraviolet damage to mouse skin.Methods The study was an experimental study.Fifty-four female C57BL/6J wild-type mice aged 6 to 8 weeks were divided into Vγ4 T cell depletion group and control group(27 mice in each group)according to the random number table,and the Armenian hamster anti-mouse Vγ4 T cell receptor(TCR)monoclonal antibody of 200 pg and an equal amount of homologous control IgG antibody were intraperitoneally injected,respectively.At one week after injection(the same time point to harvest mice below),dermal cells and lymph node cells were respectively extracted from the back skin tissue,armpit and inguinal lymph nodes of 3 mice in each group(mice in following study were all taken from these 2 groups),and the proportions of Vγ4 T cells in dermal cells and lymph node cells were detected by flow cytometry.Five mice from each group were harvested for observation of skin on the back and skin tissue structure was observed and the epidermal tissue thickness was measured after hematoxylin-eosin(HE)staining.Five mice from each group were harvested for detection of proportion of dendritic epidermal T cells(DETCs)in epidermal cells by flow cytometry after extracted.Three mice were taken from each group and recruited in Vγ4 T cell depletion+5 times ultraviolet irradiation(UVR)group and control+5 times UVR group,respectively,then UVR was administered once per day for 5 times,and the condition of skin on the back was observed immediately after daily irradiation.Five mice were taken from each group and divided into Vγ4 T cell depletion+1 UVR group and control+1 UVR group,respectively.Immediately after one UVR treatment,the epidermal tissue thickness was measured after HE staining.Three mice from each group were selected and recruited in Vγ4 T cell depletion alone group and control alone group,then 3 mice from each group rwere recruited in Vγ4 T cell depletion+1 time UVR group and control+1 time UVR group,respectively,and were treated as before.The mRNA expressions of insulin-like growth factor-Ⅰ(IGF-Ⅰ),keratinocyte growth factor(KGF),Vγ5 TCR,interleukin-15(IL-15),IL-1β,IL-23,natural killer group 2 member D(NKG2D),histocompatibility antigen 60(H60),mouse UL16-binding protein-like transcript 1(Mult1),and retinoic acid early inducible protein 1(Rae1)in the epidermal tissue were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction.Results At one week after injection,the proportions of Vγ4 T cells in dermal cells and lymph node cells of mice in Vγ4 T cell depletion group were significantly lower than those in control group(with t values of 27.99 and 13.12,respectively,P＜0.05);there were no statistically significant differences in the skin general condition and tissue structure of mice between Vγ4 T cell depletion group and control group;the epidermal tissue thickness of mice between Vγ4 T cell depletion group and control group was similar(P＞0.05);the proportion of DETCs in epidermal cells of mice in Vγ4 T cell depletion group was(3.9±0.8)％,which was significantly higher than(1.6± 0.5)％in control group(t=4.84,P＜0.05).Compared with that in control+5 times UVR group,the skin scale increased after one UVR treatment,scaly scab appeared after 2 times of irradiation,and scaly scab increased significantly after 3 to 5 times of irradiation in Vγ4 T cell depletion+5 times UVR group.Immediately after UVR treatment,the epidermal tissue thickness of mice in Vγ4 T cell depletion+1 time UVR group was significantly increased compared with that in control+1 time UVR group(t=11.50,P＜0.05).Compared with those in control alone group,the mRNA expression of Vγ5 TCR in the epidermal tissue of mice in Vγ4 T cell depletion alone group was up-regulated(t=41.16,P＜0.05),while the mRNA expression of IL-23 was down-regulated(t=6.52,P＜0.05);compared with those in control alone group,the mRNA expressions of Vγ5 TCR and KGF in the epidermal tissue of mice in control+1 time UVR group were significantly up-regulated(with t values of 15.22 and 13.22,respectively,P＜0.05),while the mRNA expressions of IGF-Ⅰ and IL-23 were significantly down-regulated(with t values of 3.71 and 4.95,respectively,P＜0.05);compared with those in Vγ4 T cell depletion alone group,the mRNA expressions of IGF-Ⅰ and KGF in the epidermal tissue of mice in Vγ4 T cell depletion+1 time UVR group were significantly up-regulated(with tvalues of 11.40 and 18.88,respectively,P＜0.05),while the mRNA expression of IL-1β was significantly down-regulated(t=4.42,P＜0.05);compared with those in control+1 time UVR group,the mRNA expressions of Vγ5 TCR,IGF-Ⅰ,and KGF in the epidermal tissue of mice in Vγ4 T cell depletion+1 time UVR group were significantly up-regulated(with t values of 4.52,15.24,and 9.43,respectively,P＜0.05);the mRNA expression of IL-15 in the epidermal tissue of mice in these 4 groups was generally similar(P＞0.05).Compared with those in control alone group,the mRNA expressions of NKG2D and Rae1 in the epidermal tissue of mice in Vγ4 T cell depletion alone group were significantly up-regulated(with t values of 3.67 and 47.40,respectively,P＜0.05),the mRNA expressions of NKG2D,Mult1,and Rae1 in the epidermal tissue of mice in control+1 time UVR group were significantly up-regulated(with t values of 5.30,6.50,and 9.16,respectively,P＜0.05);compared with those in Vγ4 T cell depletion alone group,the mRNA expressions of NKG2D,H60,Mult1,and Rae1 in the epidermal tissue of mice in Vγ4 T cell depletion+1 time UVR group were significantly down-regulated(with t values of 4.57,4.13,4.67,and 27.36,respectively,P＜0.05);compared with those in control group+1 time UVR group,the mRNA expressions of NKG2D,H60,Mult1,and Rae1 in the epidermal tissue of mice in Vγ4 T cell depletion+1 time UVR group were significantly down-regulated(with t values of 5.77,8.18,12.90,and 8.08,respectively,P＜0.05).Conclusions The clearance of Vγ4 T cells is conducive to the proliferation and down-regulation of cytotoxicity of DETCs,and may promote the repair of mouse epidermal damage after UVR.
Ultraviolet raysSkinEpidermisInsulin-like growth factor ⅠVγ4 T cellsDendritic epidermal T cellsNatural killer group 2 member D
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