Heat stress induced in vitro affects cell viability and gene expression of dermal fibroblasts from bovine and buffalo

Aim of study: To evaluate the response of dermal fibroblasts to heat stress and different time exposures on the cell survival and gene expression. Area of study: Belém city, Pará state. Brazil. Material and methods: Fibroblasts were isolated from ear skin of bovine (n= 4) and buffalo (n= 4), cultured in vitro until the 3rd passage and submitted to heat stress at 42°C for 3, 6 and 12 h, except for the negative control (38.5°C for 24 h). Cell survival was measured using Trypan blue, and RNA isolation was performed using Trizol method following qRT-PCR to quantify the relative expression of the inducible heat shock protein HSPA1A, the pro-apoptotic BAX and pro-inflammatory IFN-γ genes. Main results: Heat stress induced in vitro affected the cell viability and gene expression in a time-dependent manner. Gene expression was relatively lower in buffalo (p<0.05) than in bovine. Until 3 h of heat stress, HSPA1A showed a slight increase in both bovine and buffaloes, and BAX was 5.82-fold greater in bovine (p<0.05). After 6 h, HSPA1A was 75.81-fold (p<0.0001) and INF-γ was 20.15-fold greater (p<0.05) in bovine than buffalo. Only after 6 h the cell viability started to decrease significantly (p<0.05) in both species. Research highlights: Dermal fibroblasts of buffaloes and bovine were sensitive to heat stress induced in vitro, which was most detrimental to cell survival after 6 h. The expression of HSPA1A, BAX and INF-γ genes in response to heat stress indicate a slight sensibility of the dermal fibroblasts of bovine compared to their buffalo counterpart.