Antidepressant-like activity of Bezafibrate in mice models of depression: a behavioral and neurobiological characterization

Abstract

Background: Depression represents a major global public health challenge, inflicting profound suffering on patients while imposing substantial socioeconomic burdens on families and healthcare systems. Although monoamine-based antidepressants remain first-line pharmacotherapy, accumulating clinical evidence reveals several limitations of these medications, including delayed pharmacodynamics and low remission rates. Therefore, it is necessary to search for new drugs and develop effective strategies for depression treatment. Bezafibrate (BEZ), which can activate proliferator-activated receptor a (PPARα), exhibit various biological functions, such as improving mitochondrial function, reducing neuroinflammation, and improving cognitive function. This study is to explore whether BEZ has antidepressant-like effects and its potential mechanisms.

Methods: The antidepressant effects and potential mechanisms of BEZ were assessed by using forced swim test, tail suspension test, sucrose preference test, Western blot, gene interference, and immunofluorescence in the chronic unpredictable mild stress (CUMS) models of depression.

Results: Results showed that BEZ treatment significantly reversed depressive behavior in CUMS mice. The administration of BEZ obviously promoted the expression of PPAR, enhanced the BDNF signaling pathway, promoted hippocampal neurogenesis in CUMS mice. In addition, the pharmacologcial inhibitors GW6471 and K252a were obviously prevented the antidepressant effect of BEZ. Furthermore, gene knockdown of hippocampal PPARα or BDNF by using AAV-PPARα-shRNA-EGFP and AAV-BDNF-shRNA-EGFP, can remarkably inhibit the antidepressant effect of BEZ.

Conclusion: Collectively, the behavioral and neurobiological results demonstrate that BEZ exhibits antidepressant-like activity through PPARα/BDNF signaling pathway and may use as a potential antidepressant.

Keywords: BNDF; Bezafibrate; CUMS; PPARα; depression.

FIGURE 1

BEZ treatment significantly improves depressive behaviors in CUMS-induced mice. (A) Schematic timeline of the experimental procedures. (B) The immobility duration of FST was obviously decreased in the CUMS-induced mice after BEZ treatment. (C) The immobility duration of TST was notably reduced in the CUMS-induced mice after BEZ treatment. (D) The sucrose preference was significantly increased in the CUMS-induced mice after BEZ treatment. *P < 0.05, **P < 0.01, ***P < 0.001, n = 10 biological replicates.

FIGURE 2

BEZ administration promotes the expression levels of the hippocampal PPARα and BDNF signaling pathway in CUMS-induced mice. (A) The expression levels of PPARα, BDNF, pTrkB, TrkB, pAKT, AKT, pERK, ERK, pCREB, and CREB were quantified by Western blot analysis. (B) The statistical analysis of protein levels. **P < 0.01, ***P < 0.001, n = 5 biological replicates.

FIGURE 3

BEZ treatment promotes hippocampal neurogenesis in the CUMS-induced mice. (A) Immunofluorescent staining of DCX in the DG region, Scale bar = 150 μm. (B) Representative images of confocal microscopy and corresponding analyses of the number of DCX positive cells in the DG region. ***P < 0.001, n = 5 biological replicates.

FIGURE 4

Blockade of the PPARα and BDNF signaling pathway by GW6471 and K252a abolished the antidepressant efficacy of BEZ in mice. (A) Mice in the (CUMS + BEZ + GW6471)-treated and (CUMS + BEZ + K252a)-treated group spent significantly more time being immobile than mice in the (CUMS + BEZ)-treated groups in the FST. (B) Mice in the (CUMS + BEZ + GW6471)-treated and (CUMS + BEZ + K252a)-treated group spent significantly more time being immobile than mice in the (CUMS + BEZ)-treated groups in the TST. (C) Mice in the (CUMS + BEZ + GW6471)-treated group and (CUMS + BEZ + K252a)-treated group displayed notably lower sucrose preference than mice in the (CUMS + BEZ)-treated group. *P < 0.05, **P < 0.01, n = 10 biological replicates.

FIGURE 5

Hippocampal PPARα-knockdown by PPARα-shRNA and BDNF-knockdown by BDNF-shRNA. (A) Fluorescence images of a fixed hippocampal slice which expressed AAV-PPARα-shRNA-EGFP 2 weeks after its stereotactic infusion. The scale bars of representative and enlarged images are 400 and 50 μm, respectively. The following Western blotting results confirmed the silencing effects of PPARα-shRNA on the protein expression of hippocampal PPARα. ***P < 0.001, n = 5 biological replicates. (B) Fluorescence images of a fixed hippocampal slice which expressed AAV-BDNF-shRNA-EGFP 2 weeks after its stereotactic infusion. The scale bars of representative and enlarged images are 400 and 50 μm, respectively. The following Western blotting results confirmed the silencing effects of BDNF-shRNA on the protein expression of hippocampal BDNF. ***P < 0.001, n = 5 biological replicates.

FIGURE 6

Hippocampal PPARα-knockdown by PPARα-shRNA abolished the antidepressant activity of BEZ in mice. (A) Mice in the (CUMS + BEZ + BDNF-shRNA)-treated group spent significantly more time being immobile than mice in the (CUMS + BEZ)-treated and (CUMS + BEZ + control-shRNA)-treated groups in the FST. (B) Mice in the (CUMS + BEZ + PPARα-shRNA)-treated group spent significantly more time being immobile than mice in the (CUMS + BEZ)-treated and (CUMS + BEZ + control-shRNA)-treated groups in the TST. (C) Mice in the (CUMS + BEZ + PPARα-shRNA)-treated displayed notably lower sucrose preference than mice in the (CUMS + BEZ)-treated and (CUMS + BEZ + control-shRNA)-treated groups. *P < 0.05, **P < 0.01, n = 10 biological replicates.

FIGURE 7

Hippocampal BDNF-knockdown by BDNF-shRNA abolished the antidepressant activity of BEZ in mice. (A) Mice in the (CUMS + BEZ + BDNF-shRNA)-treated group spent significantly more time being immobile than mice in the (CUMS + BEZ)-treated and (CUMS + BEZ + control-shRNA)-treated groups in the FST. (B) Mice in the (CUMS + BEZ + BDNF-shRNA)-treated group spent significantly more time being immobile than mice in the (CUMS + BEZ)-treated and (CUMS + BEZ + control-shRNA)-treated groups in the TST. (C) Mice in the (CUMS + BEZ + BDNF-shRNA)-treated displayed notably lower sucrose preference than mice in the (CUMS + BEZ)-treated and (CUMS + BEZ + control-shRNA)-treated groups. *P < 0.05, **P < 0.01, n = 10 biological replicates.