Age and sex affect TGFβ2-induced ocular hypertension in C57BL/6J mice

Abstract

Glaucoma is a leading cause of blindness worldwide. The loss of vision in glaucoma patients is due to optic nerve damage. The most important risk factor of glaucoma is elevated intraocular pressure (IOP) which is due to glaucomatous changes in the trabecular meshwork. Animal models, especially mouse models for ocular hypertension (OHT), are important for studying glaucoma. Published studies showed that 2.5 × 10⁷ PFU adenoviral vectors expressing the biologically active form of human TGFβ2 elevate IOP in female C57BL/6J mice when they are intravitreally delivered. In this study, we found that 2.5 × 10⁷ PFU adenoviral TGFβ2 vector did not elevate IOP in 3- or 5-month old male C57BL/6J mice. In contrast, 5 × 10⁷ PFU of the same viral vectors elevated IOP in both 3- and 5-month old male C57BL/6J mice. Also, 5-month old mice showed earlier OHT and higher IOP compared to 3-month old mice. In summary, our data showed that age and sex play roles in adenoviral vector-mediated TGFβ2-induced OHT in C57BL/6J mice.

Keywords: Glaucoma; Intraocular pressure; Mouse model; Ocular hypertension; TGFβ2.

Figure 1:

C57BL/6J male mice injected with 2.5X10⁷ PFU Ad5-CMV-TGFβ2 did not develop OHT. Three-month old (A) and five-month old (B) male C57BL/6J mice were intravitreally injected with Ad5-CMV-TGFβ2 (red dots and lines) to one of the eyes and the fellow eye received Ad5-CMV-GFP as a control (blue dots and lines). Student’s paired t-test was used to compare IOP between paired eyes at each time points, and “*” was used to show significance. *: P<0.05; **: P<0.01, ****: P<0.0001. Also, one-way ANOVA was used to compare IOP at each time point with the baseline IOP, and “#” was used to show significance of TGFβ2 eyes. #: P<0.05. Error bars: standard deviations. (C): TGFβ2 expression levels in mouse TM tissues determined by qPCR. Five pairs of eyes were used for each age group and the level of TGFβ2 in Ad5-GFP injected eyes were set at 1. (D): TGFβ2 expression levels in the mouse aqueous humor determined by ELISA (the same eyes as in C). Five aqueous humor samples from the sample group were pooled. (E) and (F): immunostaining of TGFβ2 in 3-month and 5-month old mouse eyes, respectively. (G) and (H): immunostaining of EDA fibronectin (EDA-FN) in 3-month and 5-month old mouse eyes, respectively. C: cornea; CB: ciliary body; I: iris; SC: Schlemm’s canal; TM: trabecular meshwork. Scale bars: 20µM.

Figure 2:

C57BL/6J male mice injected with 5X10⁷ PFU Ad5-CMV-TGFβ2 developed OHT. Three-month old (A) and five-month old (B) male C57BL/6J mice were intravitreally injected with Ad5-CMV-TGFβ2 (red dots and lines) to one of the eyes and the fellow eye received Ad5-CMV-GFP as a control (blue dots and lines). Student’s paired t-test was used to compare IOP between paired eyes at each time points, and “*” was used to show significance. **: P<0.01, ***: P<0.001. Also, one-way ANOVA was used to compare IOP at each time point with the baseline IOP, and “#” was used to show significance of TGFβ2 eyes. #: P<0.05. ##: P<0.01. Error bars: standard deviations. (C): TGFβ2 expression levels in mouse TM tissues determined by qPCR. Five pairs of eyes were used for each age group and the level of TGFβ2 in Ad5-GFP injected eyes were set at 1. (D): TGFβ2 expression levels in the mouse aqueous humor determined by ELISA (the same eyes as in C). Five aqueous humor samples from the sample group were pooled. (E) and (F): immunostaining of TGFβ2 in 3-month and 5-month old mouse eyes, respectively. (G) and (H): immunostaining of EDA fibronectin (EDA-FN) in 3-month and 5-month old mouse eyes, respectively. C: cornea; CB: ciliary body; I: iris; SC: Schlemm’s canal; TM: trabecular meshwork. Scale bars: 20µM.