Davidson B D, Hardy K, Laporta J
Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI 53706.
JDS Commun. 2025 Jul 16;6(5):694-699. doi: 10.3168/jdsc.2025-0786. eCollection 2025 Sep.
Homeostasis and thermoregulation depend on the interplay of the hair and skin. Maternal heat stress in late gestation triggers postnatal hair and skin adaptations in daughters and granddaughters. Herein, we investigated the transgenerational effects of late-gestation heat stress on the hair and skin of the great-granddaughters. Pregnant dams (F) were heat stressed (shade) or cooled (shade, fans, water soakers) during the last ~56 d of gestation in a subtropical summer. The first generation of heifers (F) that experienced in utero heat stress (HT) or cooling (CL) were managed as a cohort until they gave birth to the second generation of heifers (F) that experienced heat stress (HT) or cooling (CL) as a germ cell within the F fetal ovaries. All F heifers were managed as a cohort and gave birth to the third generation of heifers (F; great-granddaughters) that were unexposed to the F treatments (HT and CL). At 70 d of age, a hair sample and skin biopsy were collected from the neck on a subset of F heifers (n = 6/group). Hair length and diameter; skin epidermis thickness and area; dermis thickness; sweat gland (SWTG) number, area, and depth; and sebaceous gland (SEBG) number, area, and depth were evaluated using hematoxylin and eosin staining and analyzed in ImageJ. Data were analyzed using PROC MIXED in SAS. No differences were captured in hair length or diameter, epidermis thickness or area, depth of the shallowest SWTG, depth of the SEBG, dermis thickness, and the number or size of SWTG. The HT had fewer (13.3 vs. 17.8 ± 1.1 glands) and smaller SEBG (61,641 vs. 89,963 ± 6,768 µm), relative to CL. Although SWTG number or size did not differ, distance from the skin surface to the deepest SWTG tended to be shorter in the HT (1.1 vs. 1.3 ± 0.04 mm). Late-gestation heat stress alters SEBG size and number and SWTG localization of F heifers, suggesting a transgenerational programming of postnatal thermal adaptivity.
内环境稳态和体温调节依赖于毛发与皮肤的相互作用。妊娠后期母体的热应激会引发子代和孙代出生后毛发与皮肤的适应性变化。在此，我们研究了妊娠后期热应激对曾孙女代毛发与皮肤的跨代效应。在亚热带夏季，怀孕的母畜（F代）在妊娠的最后约56天接受热应激（置于阴凉处）或降温处理（置于阴凉处、使用风扇、喷水）。第一代经历子宫内热应激（HT）或降温（CL）的小母牛（F代）作为一个群体进行管理，直至它们产下第二代小母牛（F代），第二代小母牛在F代胎儿卵巢内作为生殖细胞经历了热应激（HT）或降温（CL）。所有F代小母牛作为一个群体进行管理，并产下了未接受F代处理（HT和CL）的第三代小母牛（F代；曾孙女代）。在70日龄时，从一部分F代小母牛（每组n = 6）的颈部采集毛发样本和皮肤活检组织。使用苏木精和伊红染色评估毛发长度和直径、皮肤表皮厚度和面积、真皮厚度、汗腺（SWTG）数量、面积和深度以及皮脂腺（SEBG）数量、面积和深度，并在ImageJ中进行分析。数据使用SAS中的PROC MIXED进行分析。在毛发长度或直径、表皮厚度或面积、最浅SWTG的深度、SEBG的深度、真皮厚度以及SWTG的数量或大小方面未发现差异。相对于CL，HT的SEBG数量更少（13.3个对17.8 ± 1.1个腺体）且更小（61,641平方微米对89,963 ± 6,768平方微米）。尽管SWTG数量或大小没有差异，但HT中从皮肤表面到最深SWTG的距离往往更短（1.1毫米对1.3 ± 0.04毫米）。妊娠后期热应激会改变F代小母牛的SEBG大小和数量以及SWTG定位，表明出生后热适应性存在跨代编程。
